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14,200 | High incidence of cardiovascular complications in pheochromocytoma. | Excess of catecholamines in pheochromocytoma is usually accompanied with classical symptoms and signs. In some cases, severe cardiovascular complications (e. g., heart failure, myocardial infarction) may occur. We performed a retrospective analysis focused on the incidence of cardiovascular complications (classified as follows: arrhythmias, myocardial involvement or ischemia and atherosclerosis, cerebrovascular impairment) before the establishment of diagnosis of pheochromocytoma among 145 subjects treated in our hospital. Cardiovascular complications occurred in 28 subjects, but these subjects did not differ significantly from subjects without complications in age, gender, body mass index, paroxysmal symptoms, symptom duration, tumor dimension, catecholamine secretory phenotype, and incidence of hypertension or diabetes mellitus. Arrhythmias occurred in 15 subjects (2 arrhythmia types in 2 subjects): atrial fibrillation in 9 subjects, supraventricular tachycardia in 3 cases, and ventricular tachycardia in 2 patients. Significant bradycardia was noted in 3 cases. Five subjects presented with heart failure with decreased systolic function (takotsubo-like cardiomyopathy found in 2 cases). One subject suffered from hypertrophic obstructive cardiomyopathy. Seven subjects presented with non-ST-segment elevation myocardial infarction, 2 patients with ST-segment myocardial infarction, and 1 subject underwent coronary artery bypass grafting. Two subjects suffered from significant peripheral atherosclerosis. Among cerebrovascular complications, transient ischemic attack was found in 3 cases, 2 subjects suffered from stroke, and subarachnoidal bleeding occurred in 1 patient. One subject suffered from diffuse neurological impairment due to multiple ischemic white matter lesions. These data show relatively high incidence of cardiovascular complications (19.3%) in subjects with pheochromocytoma. Early diagnosis is mandatory to prevent severe complications in pheochromocytoma. |
14,201 | Clinical pharmacokinetics and therapeutic efficacy of esmolol. | Esmolol is a unique cardioselective β(1)-receptor blocking agent with a rapid onset and short duration of action. Since our previous review in 1995, the pharmacokinetics and efficacy of esmolol have been investigated in a number of acute care settings. Three studies investigated the pharmacokinetics and safety of esmolol in the paediatric population. The disposition of esmolol in children was found to be linear with plasma concentrations increasing in proportion to dose over the ranges studied. The pharmacokinetic estimates for esmolol showed a shorter elimination half-life (t(½)) [2.7-4.8 minutes] and a higher clearance (281 mL/kg/min) in newborns and infants than that found in children (>2 years old) and adults. Dosing requirements to achieve targeted blood pressure in post-coarctectomy patients were substantially higher (mean 700 μg/kg/min) than that used in adults. Esmolol was effective in controlling hypertension following cardiac surgery and terminating supraventricular arrhythmias in children. The efficacy of esmolol has been established in a variety of patients, including those with unstable angina, myocardial ischaemia, supraventricular arrhythmias, peri- and postoperative tachycardia and hypertension, and electroconvulsive therapy. With careful titration and monitoring, esmolol can be used effectively in patients with congestive heart failure and chronic obstructive lung disease because of its unique short t(½) and β(1)-selectivity. Different dosage schedules have been developed depending on clinical setting and diagnosis. Generally, a loading dose of ≤500 μg/kg/min over 1 minute is administered followed by a continuous infusion of 25-300 μg/kg/min. Hypotension, being the primary adverse effect, can be minimized by careful dosage titration and patient monitoring. In the perioperative setting involving tracheal intubation and extubation, a number of recent studies have suggested that titration of esmolol to a haemodynamic endpoint can be safe and effective, resulting in a decreased incidence of myocardial ischaemia. The most effective regimen in attenuating the response to heart rate and blood pressure after laryngeal tracheal intubation was a loading dose of 500 μg/kg/min for 4 minutes followed by a continuous infusion of 200-300 μg/kg/min. In cardiac and non-cardiac surgical patients esmolol has been shown to decrease episodes of myocardial ischaemia and arrhythmias. In the perioperative period for non-cardiac surgery routine use of β-blockers (β-adrenoceptor antagonists) is no longer recommended. However, in patients at high risk for myocardial ischaemia or undergoing high-risk surgery where a β-blocker is indicated, esmolol is the ideal perioperative agent to minimize the risk of hypotension and bradycardia based on its pharmacodynamic and pharmacokinetic characteristics. For postoperative patients in atrial fibrillation, esmolol achieves rapid ventricular rate control. However, for the prevention of postoperative atrial fibrillation esmolol provides no advantage over oral β-blockers. In other situations where emergent β-blockade is required, such as electroconvulsive therapy, esmolol has been shown to effectively control haemodynamic response. After more than 2 decades of use esmolol continues to provide an important therapeutic option in the acute care setting. |
14,202 | Neuroprotection and hypothermia in infants and children. | Brain injury is the leading cause of death in pediatric ICU. Current evidence supports the use of therapeutic hypothermia (TH) in unconscious patients after out-of-hospital cardiac arrest when the initial heart rhythm was ventricular fibrillation. TH has been proved to be also beneficial in term neonates after hypoxic-ischemic encephalopathy (HIE) and in children with traumatic brain injury (TBI). Recent reports have also investigated TH for the treatment of superrefractory status epilepticus. The clinical application of TH is based on the possibility to inhibit or lessen a myriad of destructive processes (including excitotoxicty, neuroinflammation, apoptosis, free radical production, seizure activity, blood- brain barrier disruption, blood vessel leakage) that take place in the injured tissue following ischemia-reperfusion. TH may also represent a useful tool when conventional therapy fails to achieve an effective control of elevated intracranial pressure. This review is aimed to provide an update of the available literature concerning this intriguing topic. |
14,203 | Left ventricular posterior wall thickness is an independent risk factor for paroxysmal atrial fibrillation. | Atrial fibrillation is the most common significant cardiac arrhythmia in clinical practice, but its risk factors remain to be clarified. We have hypothesized that left ventricular posterior wall thickness is an independent risk factor for paroxysmal atrial fibrillation (PAF).</AbstractText>A total of 166 consecutive patients with paroxysmal atrial fibrillation were included in this study. Another 166 healthy check-up people, strictly age and sex-matched, were enrolled as controls in the same period. Univariable analysis and multivariable conditional logistic stepwise regression analysis were conducted. Receiver operating characteristic (ROC) curve analysis was performed on those significant indices obtained from the multivariable logistic regression analysis.</AbstractText>The multivariable stepwise analysis identified left ventricular posterior wall thickness, left atrial diameter tricuspid insufficiency and residence (countryside) as independent predictors for paroxysmal atrial fibrillation. Receiver operating characteristic curve analysis demonstrated the cutoff values of those risk factors aforementioned.</AbstractText>In this strictly age and sex-matched population-based sample, left ventricular posterior wall thickness, left atrial diameter, tricuspid insufficiency and residence were predictive risks for paroxysmal atrial fibrillation. This study offers novel information therapeutically beyond that provided by traditional clinical atrial fibrillation risk factors.</AbstractText> |
14,204 | Automatic assessment of atrial pacing threshold in current medical practice. | The aim of this study was to validate the ambulatory automatic atrial threshold monitoring algorithm by comparing the measurements assessed by the automatic system and those evaluated manually by the physician at discharge, 2- and 8-month follow-up sessions.</AbstractText>This is an observational multicentric prospective study of 352 patients implanted with EnPulse(®) DR pacemakers. Mean age was 76.3 ± 9.4 years. Indications of pacing were atrio-ventricular block (AVB) (64%) and sinus dysfunction (SD) or brady-tachy syndrome (36%). The automatic atrial threshold monitoring function was maintained at nominal programming state with daily measurement scheduled at 1:00 am. Ambulatory automatic atrial threshold assessment was possible for 91.5% of patients at discharge, 97.3% at 2 months, and 95.7% at 8 months. Causes of the unsuccessful attempts to perform automatic atrial threshold were atrial arrhythmias or permanent atrial and ventricular pacing. Feasibility is significantly better for AVB indication than SD indication due to more frequent occurrence of atrial fibrillation (AF). At each stage, there is a strict correlation between the automatic measurements and those conducted manually by the physician with a P < 0.001.</AbstractText>Feasibility of ambulatory automatic atrial threshold is good. Results of the study show excellent correlation between the two methods for atrial threshold: there is no statistical difference between manual and automatic measurements during follow-up.</AbstractText> |
14,205 | Catheter ablation utilizing remote magnetic navigation: a review of applications and outcomes. | The utilization of the NIOBE™ magnetic navigation system (MNS, Stereotaxis, St. Louis, MO, USA) has increased significantly since the first published report in 2002. There has been much enthusiasm for this technology as a means to reduce radiation exposure to the patient and physician alike, and potentially decrease risks associated with catheter manipulation by less experienced operators. However, there are limited data regarding the acute, intermediate, and long-term results and procedural characteristics from ablation procedures utilizing this system. We present a review of the outcomes and procedural data available to date. |
14,206 | Impact of right ventricular apical pacing and its frequency on left atrial function. | Right ventricular apical (RVA) pacing induces left ventricular (LV) dyssynchrony, increases the risk of persistent atrial fibrillation in the long term. The aim was to investigate the effects of RVA pacing on left atrial (LA) function, which are unknown.</AbstractText>Echocardiographic evaluation including LV dyssynchrony based on conventional Doppler, tissue Doppler imaging and speckle tracking strain echocardiography was done before and after (12 months) single-chamber ventricular pacemaker implantation in 40 patients with sick sinus syndrome. Patients were divided to 2 groups, according to the RVA pacing frequency (group I had higher pacing rate of more than 50% and group II, less than 50%).</AbstractText>There was no significant difference in LV ejection fraction, however, mean global LV strain, myocardial performance index, and parameters of LV dyssynchrony had shown significant changes after 12 months of RVA pacing. There were also significant increase in the LA volume index and the reduction of peak systolic LA strain and strain rate (SR), peak early and late diastolic SR after RVA pacing. Moreover, there was significant deterioration of LV dyssynchrony and both LA and LV longitudinal function in even group II. LA functional deterioration and LA volume was significantly correlated with the frequency of RVA pacing.</AbstractText>LV dyssynchrony, induced by RVA pacing, significantly impaired active LA contraction and passive stretching, and these findings were shown in the patients with even less than 50% of RVA pacing. Impairment of LA strain/SR was significantly correlated with the frequency of RVA pacing.</AbstractText> |
14,207 | Discriminating clinical features of heart failure with preserved vs. reduced ejection fraction in the community. | Heart failure (HF) is a major public health burden worldwide. Of patients presenting with HF, 30-55% have a preserved ejection fraction (HFPEF) rather than a reduced ejection fraction (HFREF). Our objective was to examine discriminating clinical features in new-onset HFPEF vs. HFREF.</AbstractText>Of 712 participants in the Framingham Heart Study (FHS) hospitalized for new-onset HF between 1981 and 2008 (median age 81 years, 53% female), 46% had HFPEF (EF >45%) and 54% had HFREF (EF ≤45%). In multivariable logistic regression, coronary heart disease (CHD), higher heart rate, higher potassium, left bundle branch block, and ischaemic electrocardiographic changes increased the odds of HFREF; female sex and atrial fibrillation increased the odds of HFPEF. In aggregate, these clinical features predicted HF subtype with good discrimination (c-statistic 0.78). Predictors were examined in the Enhanced Feedback for Effective Cardiac Treatment (EFFECT) study. Of 4436 HF patients (median age 75 years, 47% female), 32% had HFPEF and 68% had HFREF. Distinguishing clinical features were consistent between FHS and EFFECT, with comparable discrimination in EFFECT (c-statistic 0.75). In exploratory analyses examining the traits of the intermediate EF group (EF 35-55%), CHD predisposed to a decrease in EF, whereas other clinical traits showed an overlapping spectrum between HFPEF and HFREF.</AbstractText>Multiple clinical characteristics at the time of initial HF presentation differed in participants with HFPEF vs. HFREF. While CHD was clearly associated with a lower EF, overlapping characteristics were observed in the middle of the left ventricular EF range spectrum.</AbstractText> |
14,208 | Phosphodiesterase inhibitors, congestive heart failure, and sudden death: time for re-evaluation. | A 42-year-old diabetic man was admitted with systolic heart failure and pulmonary hypertension being treated with sildenafil for the previous year. With an increase in creatinine, he experienced 3 episodes of ventricular tachycardia and ventricular fibrillation. Withdrawal of the phosphodiesterase (PDE) inhibitor resulted in no further episodes of dysrhythmias. The basic pharmacology of PDE inhibitors is presented and the use of PDE-3 inhibitors for the treatment of heart failure causing an increase in sudden death is also reviewed. There have been several cases of sudden death associated with sildenafil use and with its increasing use in patients with severe pulmonary hypertension and decompensated heart failure. The authors also reviewed the electrophysiologic effects of PDE-5 inhibitors associated with their use. The crossover between PDE-3 and PDE-5 inhibitors is also discussed and caution is urged when contemplating the use of PDE-5 inhibitors in patients with systolic heart failure and pulmonary hypertension. |
14,209 | Relationship between plasma concentrations of N-terminal pro brain natriuretic peptide and the characteristics and outcome of patients with a clinical diagnosis of diastolic heart failure: a report from the PEP-CHF study. | The aim of this study was to explore the relationships between plasma concentrations of N-terminal pro brain natriuretic peptide (NT-proBNP) and characteristics and prognosis of patients with heart failure and preserved (HFPEF) left ventricular ejection fraction (LVEF). No substantial trial has shown that treatment alters prognosis in patients with HFPEF due, in part, to much lower than anticipated event rates. The lack of a simple, objective test to identify patients with HFPEF at increased risk of cardiovascular events would be valuable.</AbstractText>The Perindopril in Elderly People with Chronic Heart Failure Trial (PEP-CHF) was a randomized, controlled trial comparing perindopril and placebo in patients with symptoms and signs of heart failure who had an LVEF >40% and evidence of LV diastolic dysfunction. The primary endpoint was all-cause mortality or heart failure-related hospitalization. NT-proBNP was measured in 375 patients. Quartile thresholds were 176, 409, and 1035 pg/mL. Patients in the highest quartile of NT-proBNP were older, had lower body mass, more often had atrial fibrillation, had greater atrial and ventricular dimensions and a lower LVEF, and were more likely to receive loop diuretic therapy. Compared with the first quartile of NT-proBNP, the hazard ratios for the primary endpoint in the second {1.38 [95% confidence interval (CI) 0.64-2.99]}, third [2.84 (95% CI 1.42-5.72)], and fourth [4.47 (95% CI 2.30-8.72)] quartiles were increased. In a multivariable model, NT-proBNP, but not echocardiographic measures, was associated with outcome.</AbstractText>NT-proBNP is a powerful prognostic marker in patients with HFPEF.</AbstractText> |
14,210 | Syncope in Brugada syndrome patients: prevalence, characteristics, and outcome. | The report from the 2nd Consensus Committee on BrS suggests that all patients with syncope without a "clear extracardiac cause" should have an implantable cardioverter-defibrillator (ICD). However, a clear extracardiac cause for syncope may be difficult to prove.</AbstractText>The purpose of this study was to characterize syncope in patients with Brugada syndrome (BrS).</AbstractText>All patients diagnosed with BrS at our institution between 1999 and 2010 were enrolled in a prospective registry. Patients with suspected arrhythmic syncope (group 1) were compared to patients with nonarrhythmic syncope (group 2) and to patients with syncope of doubtful origin (group 3).</AbstractText>Of 203 patients with BrS, 57 (28%; 44 male, age 46 ± 12 years) experienced at least 1 syncope. Group 1 consisted of 23 patients, all of whom received an ICD. In group 2 (17 patients), 3 received an ICD because of a positive electrophysiologic study. In group 3 (17 patients), 6 received an implantable loop recorder and 6 received an ICD. After mean follow-up of 65 ± 42 months, 14 patients in group 1 remained asymptomatic, 4 had recurrent syncope, and 6 had appropriate ICD therapy. In group 2, 9 patients remained asymptomatic and 7 had recurrent neurocardiogenic syncope. In group 3, 7 remained asymptomatic and 9 had recurrent syncope. One patient from each group died from a noncardiac cause.</AbstractText>In the present study, syncope occurred in 28% of patients with BrS. The ventricular arrhythmia rate was 5.5% per year in group 1. In 30%, the etiology of the syncope was questionable. No sudden cardiac death occurred in groups 2 and 3.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,211 | Enhancing Cardiac Resynchronization Therapy for Patients with Atrial Fibrillation: The Role of AV Node Ablation. | Cardiac resynchronization therapy (CRT) has evolved as an effective therapy for patients with congestive heart failure (CHF) and ventricular dyssynchrony, currently defined as a wide QRS on the electrocardiogram. While multiple randomized controlled trials have confirmed the favorable effects of CRT on mortality and heart failure symptoms for patients in sinus rhythm, only recently observational studies have begun to suggest a similar benefit for patients with atrial fibrillation (AF) and dyssynchrony. Yet, implementing effective biventricular pacing in patients with AF can be problematic due to competing intrinsic AV conduction. For patients with depressed ejection fractions needing AV node (AVN) ablation to control fast ventricular rates, biventricular pacing has been shown to be superior to right ventricular pacing alone. When consistent pacing (over 90% of the time) cannot be achieved in AF patients due to a rapid ventricular response despite pharmacological therapy, AVN ablation should be considered. The additional benefit of performing AVN ablation to promote biventricular pacing in patients without rapid ventricular rates remains uncertain. A randomized controlled trial is needed to test the incremental benefit of AVN ablation to promote biventricular pacing in heart failure patients with AF and wide QRS. |
14,212 | Modifications of mechanoelectric feedback induced by 2,3-butanedione monoxime and Blebbistatin in Langendorff-perfused rabbit hearts. | Myocardial stretching is an arrhythmogenic factor. Optical techniques and mechanical uncouplers are used to study the mechanoelectric feedback. The aim of this study is to determine whether the mechanical uncouplers 2,3-butanedione monoxime and Blebbistatin hinder or modify the electrophysiological effects of acute mechanical stretch.</AbstractText>The ventricular fibrillation (VF) modifications induced by acute mechanical stretch were studied in 27 Langendorff-perfused rabbit hearts using epicardial multiple electrodes and mapping techniques under control conditions (n = 9) and during the perfusion of 2,3-butanedione monoxime (15 mM) (n = 9) or Blebbistatin (10 μm) (n = 9).</AbstractText>In the control series, myocardial stretch increased the complexity of the activation maps and the dominant frequency (DF) of VF from 13.1 ± 2.0 Hz to 19.1 ± 3.1 Hz (P < 0.001, 46% increment). At baseline, the activation maps showed less complexity in both the 2,3-butanedione monoxime and Blebbistatin series, and the DF was lower in the 2,3-butanedione monoxime series (11.4 ± 1.2 Hz; P < 0.05). The accelerating effect of mechanical stretch was abolished under 2,3-butanedione monoxime (maximum DF = 11.7 ± 2.4 Hz, 5% increment, ns vs baseline, P < 0.0001 vs. control series) and reduced under Blebbistatin (maximum DF = 12.9 ± 0.7 Hz, 8% increment, P < 0.01 vs. baseline, P < 0.0001 vs. control series). The variations in complexity of the activation maps under stretch were not significant in the 2,3-butanedione monoxime series and were significantly attenuated under Blebbistatin.</AbstractText>The accelerating effect and increased complexity of myocardial activation during VF induced by acute mechanical stretch are abolished under the action of 2,3-butanedione monoxime and reduced under the action of Blebbistatin.</AbstractText>© 2012 The Authors Acta Physiologica © 2012 Scandinavian Physiological Society.</CopyrightInformation> |
14,213 | Prolongation of QTc and risk of stroke: The REGARDS (REasons for Geographic and Racial Differences in Stroke) study. | The purpose of this study was to examine the association between prolongation of QT interval corrected for heart rate (QTc) with incident stroke.</AbstractText>Unlike cardiovascular morbidity and mortality, little is known about the relationship between QTc and risk of stroke.</AbstractText>A total of 27,411 participants age 45 years and older without previous stroke from the REGARDS (REasons for Geographic and Racial Differences in Stroke) study were included in this analysis. QTc was calculated using Framingham formula (QTc(Fram)). Stroke cases were identified and adjudicated during up to 8.2 years of follow-up (median, 5.1 years).</AbstractText>The risk of incident stroke in study participants with prolonged QTc(Fram) was almost 3 times the risk in those with normal QTc(Fram) (hazard ratio [HR] [95% confidence interval (CI)]: 2.88 [2.12 to 3.92], p < 0.0001). After adjustment for demographics (age, race, and sex), traditional stroke risk factors (antihypertensive medication use, systolic blood pressure, current smoking, diabetes, left ventricular hypertrophy, atrial fibrillation, and previous cardiovascular disease), warfarin use, aspirin use, QRS duration and use of QTc-prolonging drugs, the risk of stroke remained significantly high (HR [95% CI]: 1.67 [1.16 to 2.41], p = 0.0061) and was consistent across several subgroups of REGARDS study participants. Similar results were obtained when the risk of stroke was estimated per 1-SD increase in QTc(Fram), (HR [95% CI]: 1.12 [1.03 to 1.21], p = 0.0053 in multivariable-adjusted model) and when other QTc correction formulas including those of Hodge, Bazett, and Fridericia were used.</AbstractText>QTc prolongation is associated with a significantly increased risk of incident stroke independent of traditional stroke risk factors. Examining the risk of stroke associated with QTc-prolonging drugs may be warranted.</AbstractText>Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,214 | Advances in catheter ablation: a burning trail! | The last 15 years have literally witnessed a revaluation in the management of patients with cardiac arrhythmia. Although the visibility for these advances has come from successful catheter ablation of common arrhythmia, these advances could not have occurred without the preceding details where in painstaking anatomic and electrophysiological studies were done. The options available to patients with AF and certain ventricular arrhythmias were simply not present two decades ago. An appreciation of the role of extra cardiac structures including the thoracic veins, great arteries and retro-atrial ganglionated plexii along with the availability of accurate imaging and navigation techniques has fueled these great advances. The next five to ten years we will see even greater innovations as the complications and risks of arrhythmias and ablation have sought to be minimized while cardiac "electrophysiology techniques" permeate other organ systems including the brain. |
14,215 | Safety of pulmonary vein isolation and left atrial complex fractionated atrial electrograms ablation for atrial fibrillation with phased radiofrequency energy and multi-electrode catheters. | Recently, a multi-electrode catheter system using phased radiofrequency (RF) energy was developed specifically for atrial fibrillation (AF) ablation: the pulmonary vein ablation catheter (PVAC), the multi-array septal catheter (MASC), and the multi-array ablation catheter (MAAC). Initial results of small trials have been promising: shorter procedure times and low adverse event rates. In a large single-centre registry, we evaluated the adverse events associated with multi-electrode ablation catheter procedures with PVAC alone, or combined with MASC and MAAC.</AbstractText>In all, 634 consecutive patients with AF had 663 procedures with multi-electrode ablation catheters, 502 patients with the PVAC alone, 128 patients with PVAC/MASC/MAAC, 29 redo procedures with the PVAC or PVAC/MASC/MAAC, and 4 patients had a complicated transseptal puncture. Major and minor adverse events during 6 month follow-up were registered. In 15 cases (2.3%), major adverse events were seen within the first month after the procedure. These included complicated transseptal puncture (4), stroke (2), transient ischaemic attack (5), acute coronary syndrome (2), femoral pseudoaneurysm (1), and arteriovenous fistulae (1). Minor adverse events were seen in 10.7% at 6 months, mostly due to femoral haematoma (3.9%), and non-significant PV stenosis (5.2%). There was no difference in the occurrence of major adverse events between PVAC alone, or PVAC/MASC/MAAC ablation.</AbstractText>Ablation with phased RF and multi-electrode catheters is accompanied by a major adverse event rate of 2.3% within 1 month and a minor event rate of 10.7% at 6 months.</AbstractText> |
14,216 | An approach to echocardiography in hypertrophic cardiomyopathy and other causes of LVH. | Hypertrophic cardiomyopathy (HCM) is the most prevalent genetic cardiovascular disease with a prevalence of 1:500 in the general population. Its identification is of critical importance as it is a common cause of sudden death in the young and can lead to considerable morbidity, including heart failure and atrial fibrillation. There are several conditions that can mimic the phenotypic appearance of HCM on echocardiography. Echocardiography remains an invaluable tool in both initial diagnosis and regular surveillance of patients with this condition. Although no single echocardiographic parameter is ideal, a structured and comprehensive assessment of cardiac structure and function will provide invaluable clues to the diagnosis and often hint towards an alternate diagnosis. The purpose of this review is to reassess the typical echocardiographic features of HCM and to highlight echocardiographic features that may help to distinguish other causes of left ventricular hypertrophy (LVH). |
14,217 | Blood pressure and other determinants of new-onset atrial fibrillation in patients at high cardiovascular risk in the Ongoing Telmisartan Alone and in Combination With Ramipril Global Endpoint Trial/Telmisartan Randomized AssessmeNt Study in ACE iNtolerant subjects with cardiovascular Disease studies. | Evidence on new-onset atrial fibrillation in high-risk vascular patients without heart failure is limited. New-onset atrial fibrillation was a prespecified secondary objective of the Ongoing Telmisartan Alone and in Combination With Ramipril Global Endpoint Trial (ONTARGET)/Telmisartan Randomized AssessmeNt Study in ACE iNtolerant subjects with cardiovascular Disease (TRANSCEND) studies.</AbstractText>We studied 30 424 ONTARGET/TRANSCEND patients (mean age ± SD, 66.4 ± 7.0) with vascular disease or complicated diabetes who were in sinus rhythm at entry. A copy of ECG was sent to central office every time new atrial fibrillation was detected by investigators.</AbstractText>During a median follow-up period of 4.7 years, new atrial fibrillation occurred in 2092 patients (15.1 per 1000  patient-years). Risk of atrial fibrillation increased with age, SBP and pulse pressure, left ventricular hypertrophy, BMI, serum creatinine and history of hypertension, coronary artery disease and cerebrovascular disease (all P < 0.01). After adjustment for BMI and other variables, atrial fibrillation risk increased with hip circumference. History of hypertension was associated with a 34% higher risk of new atrial fibrillation. New atrial fibrillation portended an increased risk of congestive heart failure [hazard ratio 2.89, 95% confidence interval (CI) 2.45-3.40, P < 0.01] and cardiovascular death (hazard ratio 1.22, 95% CI 1.05-1.41, P < 0.01). Risk of stroke was unaffected (hazard ratio 1.14, 95% CI 0.93-1.40), whereas that of myocardial infarction was reduced (hazard ratio 0.64, 95% CI 0.50-0.82). Patients with new atrial fibrillation were more likely to receive vitamin K antagonists (P < 0.01), statins (P < 0.05) and β-blockers (P < 0.01) than those in sinus rhythm.</AbstractText>New atrial fibrillation is common in high-risk vascular patients and is associated with several risk factors including history of hypertension. Hip circumference was the strongest anthropometric predictor. Despite extensive use of modern therapies, new atrial fibrillation carries a high risk of congestive heart failure and death over a relatively short term.</AbstractText> |
14,218 | Thoracoscopic epicardial ablation of the left and right atrium. Beating heart procedure in patients with atrial fibrillation. | Atrial fibrillation (AF) is a common arrhythmia affecting approximately 1% to 2% of the general population.</AbstractText>The aim of the study was to evaluate the efficacy and safety of thoracoscopic ablation in patients with AF.</AbstractText>A total of 25 patients aged from 42 to 77 years (mean 56.4 years) with persistent or long-standing persistent AF were scheduled for the procedure. Thoracoscopic epicardial ablation of the right atrium, pulmonary veins, and left atrium was performed on the beating heart using the Cox MAZE III-based diagram, via 3 ports and 2 cm incision below the xiphoid. Exit block was always assessed. Patients were prospectively followed for 12 months after the procedure. 24-hour electrocardiography (Holter monitoring) was used to confirm the results.</AbstractText>Conduction block across ablation lines was achieved in 21 patients (84%). At 1 month of follow-up, the sinus rhythm (SR) was observed in 18 of 20 patients. At 3 months, the SR was observed in 19 patients (76%). Two patients had atrial flutter, while 3 still experienced AF. At 6 months, the SR was observed in 21 patients (84%); 2 patients still had AF, 1 patient atrial flutter, and 1 patient had a pacemaker implanted. Results of follow-up at 1 year did not differ from those at 6 months. No changes in the size of the left atrium and left ventricular ejection fraction, no deaths, stroke, transient ischemic attack, or infectious complications were observed.</AbstractText>The efficacy of epicardial thoracoscopic ablation of the left and right atrium was high, reaching 84% during 1-year follow-up. No serious complications were observed in the postoperative period (except for the need for pacemaker implantation in 1 patient).</AbstractText> |
14,219 | Electrical storm in short-QT syndrome successfully treated with Isoproterenol. | Short-QT Syndrome. A 28-year-old man was admitted after aborted sudden cardiac death while sleeping. QTc was 320 ms, suggesting short-QT syndrome (SQTS). The patient then presented with electrical storm with 8 successive episodes of ventricular fibrillation while on deep sedation and hypothermia. Isoproterenol infusion was introduced, leading to rapid cessation of any arrhythmic event. Isoproterenol can be effective in managing electrical storm in patients with SQTS. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1028-1030, September 2012). |
14,220 | Cardiac denervation procedure to treat refractory angina in a patient with Churg-Strauss syndrome and non-obstructive coronary lesions. | Cardiac involvement in Churg-Strauss syndrome is common and represents the main cause of mortality. We report the case of a patient with Churg-Strauss vasculitis, mitral regurgitation with left ventricular dysfunction, paroxysmal atrial fibrillation and refractory angina with non-significant coronary lesions. Cardiac denervation was proposed as an associated procedure to treat angina. The total removal of peri-adventitial and adventitial tissue around the superior vena cava, ascending aorta and main pulmonary trunk was performed. After 3 months of follow-up, the patient was angina-free and could resume his normal lifestyle. |
14,221 | A focus on antiarrhythmic properties of ranolazine. | Ranolazine is an antianginal drug that inhibits a number of ion currents that are important for the genesis of transmembrane cardiac action potential. It was initially developed as an antianginal agent but was found to additionally exert antiarrhythmic actions, due to its multichannel-blocking properties. In recent years, several studies about the antiarrhythmic properties of ranolazine were conducted, demonstrating the beneficial effects of this drug in both atrial and ventricular arrhythmias, such as atrial fibrillation, ventricular premature beats, ventricular tachycardia, torsades de pointes, and ventricular fibrillation. Our aim is to briefly review the main points of these studies, most more experimental than clinical. |
14,222 | Elimination of local abnormal ventricular activities: a new end point for substrate modification in patients with scar-related ventricular tachycardia. | Catheter ablation of ventricular tachycardia (VT) is effective and particularly useful in patients with frequent defibrillator interventions. Various substrate modification techniques have been described for unmappable or hemodynamically intolerable VT. Noninducibility is the most frequently used end point but is associated with significant limitations, so the optimal end point remains unclear. We hypothesized that elimination of local abnormal ventricular activities (LAVAs) during sinus rhythm or ventricular pacing would be a useful and effective end point for substrate-based VT ablation. As an adjunct to this strategy, we used a new high-density mapping catheter and frequently used epicardial mapping.</AbstractText>Seventy patients (age, 67±11 years; 7 female) with VT and structurally abnormal ventricle(s) were prospectively enrolled. Conventional mapping was performed in sinus rhythm in all, and a high-density Pentaray mapping catheter was used in the endocardium (n=35) and epicardially. LAVAs were recorded in 67 patients (95.7%; 95% confidence interval, 89.2-98.9). Catheter ablation was performed targeting LAVA with an irrigated-tip catheter placed endocardially via a transseptal or retrograde aortic approach or epicardially via the subxiphoid approach. LAVAs were successfully abolished or dissociated in 47 of 67 patients (70.1%; 95% confidence interval, 58.7-80.1). In multivariate analysis, LAVA elimination was independently associated with a reduction in recurrent VT or death (hazard ratio, 0.49; 95% confidence interval, 0.26-0.95; P=0.035) during long-term follow-up (median, 22 months).</AbstractText>LAVAs can be identified in most patients with scar-related VT. Elimination of LAVAs is feasible and safe and is associated with superior survival free from recurrent VT.</AbstractText> |
14,223 | Transient ST-segment elevation after transseptal puncture for atrial fibrillation ablation in two cases. | The present report demonstrates two cases of transient inferior ST-segment elevation accompanied by profound hypotension and bradycardia immediately after transseptal puncture for catheter ablation of atrial fibrillation. This rare complication of transseptal puncture was resolved quickly within several minutes. The most likely mechanism of this phenomenon is coronary vasospasm, although coronary embolism can not be ruled out completely. This complication is characterized as follows: (1) The right coronary artery might be the most likely involved vessel and therefore myocardial ischemia usually occurs in the inferior wall of left ventricular; (2) Reflex hypotension and bradycardia by the Bezold-Jarisch reflex secondary to inferior ischemia often occur at the same time. Though it appears to be a transient and completely reversible phenomenon, there are still potential life-threatening risks because of myocardial ischemia and profound haemodynamic instability. Clinical cardiologists should be aware of this rare complication and properly deal with it. |
14,224 | Ventricular fibrillation hampers the restoration of creatine-phosphate levels during simulated cardiopulmonary resuscitations. | Recurrences of ventricular fibrillation (VF) during cardiopulmonary resuscitation (CPR) are associated with a reduced chance of survival. The effect of VF during CPR on the myocardium is unknown. We tested the hypothesis that VF during simulated CPR reduces the restoration of the myocardial energy state and contractile function.</AbstractText>Twelve porcine hearts were isolated and perfused with the pig's own blood. First, cardiac oxygen consumption was measured by blood gas analysis. Secondly, we simulated sudden cardiac arrest by VF (7 min VF, zero flow) followed by simulated CPR (7 min, 0.3 mL/g/min perfusion rate) in the absence and presence of VF [six hearts were maintained in VF (VF-group), six were defibrillated (defib-group)]. The VF increased the cardiac oxygen consumption by 71% (0.87 ± 0.12 vs. 1.49 ± 0.14 μmol O₂/g/min; mean ± SEM, P< 0.001) compared with a ventricular rhythm of 62 beats/min. The presence of VF during simulated CPR after 7 min of cardiac arrest hampered restoration of myocardial creatine-phosphate levels compared with defibrillated hearts (61 ± 9 vs. 87 ± 7% of baseline values, respectively; P< 0.05). The cardiac contractile function was significantly higher in the defib- than in the VF-group (area under the pressure curve 2.29 ± 0.22 vs. 1.72 ± 0.14 s×mm Hg respectively; P< 0.05).</AbstractText>These data demonstrate that the cardiac oxygen consumption is increased by VF and that the presence of VF during CPR hampers the restoration of the myocardial energy state and contractility. Strategies that reduce VF duration without disrupting chest compressions will benefit the restoration of the cardiac energy state during resuscitations.</AbstractText> |
14,225 | Prevalence of atrial fibrillation in the general population and in high-risk groups: the ECHOES study. | To establish the prevalence of atrial fibrillation (AF) in the general population in the UK, and in those with risk factors.</AbstractText>The prevalence of AF on electrocardiography was established in prospectively selected groups: 3960 randomly selected from the population, aged 45+; 782 with a previous diagnosis of heart failure; and 1062 with a record of myocardial infarction, hypertension, angina, or diabetes. Patients were also assessed clinically and with echocardiography. Mortality was tracked for 8 years. Atrial fibrillation was found in 78 of the random population sample (2.0%). Prevalence was 1.6% in women and 2.4% in men, rising with age from 0.2% in those aged 45-54 to 8.0% in those aged 75 and older. Half of all cases were in patients aged 75 and older. Only 23 of the 78 (29.5%) of those in AF took warfarin. Of the 782 patients, 175 (22.4%) with a diagnosis of heart failure were in AF, with normal left ventricular function in 95 (54.3%) of these. Atrial fibrillation was found in 14 of the 244 (5.7%) of those with a history of myocardial infarction, 15 of the 388 (3.9%) of those with hypertension, 15 of the 321 (4.7%) of those with angina, and 11 of the 208 (5.3%) of diabetics. Adjusting for age and sex, mortality was 1.57 times higher for those in AF.</AbstractText>Atrial fibrillation is common in the elderly and those with clinical risk factors. Screening these groups would identify many with AF. Use of anticoagulation was low at the time of the initial assessments in the late 1990s; practice may have changed recently.</AbstractText> |
14,226 | Electrical defibrillation outcome prediction by waveform analysis of ventricular fibrillation in cardiac arrest out of hospital patients. | Indexes such as amplitude spectrum area (AMSA) and power spectrum area (PSA) obtained from electrocardiogram waveform analysis are possible predictors of outcome after electrical defibrillation for ventricular fibrillation (VF). In this study, we examined AMSA and PSA to determine whether these parameters can predict defibrillation outcome.</AbstractText>A total of 83 out-of-hospital VF victims were classified into four groups according to type of cardiac rhythm after shock: return of spontaneous circulation (ROSC), VF, pulseless electrical activity (PEA), and asystole. AMSA and PSA were calculated from electrocardiograms prior to shock and compared between groups.</AbstractText>The mean AMSA (4.0-48 Hz) in the ROSC group was 24.2 ± 8.5 mV-Hz, which was significantly higher than that in the VF and asystole groups.</AbstractText>It is possible by analyzing the AMSA of VF to predict cases where electrical defibrillation is more likely to return cardiac rhythm. Furthermore, unnecessary electrical shocks with a low possibility of ROSC can be avoided, and chest compression should be continued to prevent myocardial damage and consequently improve prognosis.</AbstractText> |
14,227 | Improved cerebral perfusion pressures and 24-hr neurological survival in a porcine model of cardiac arrest with active compression-decompression cardiopulmonary resuscitation and augmentation of negative intrathoracic pressure. | Generation of negative intrathoracic pressure during the decompression phase of cardiopulmonary resuscitation enhances the refilling of the heart. We tested the hypothesis that when compared with closed-chest manual compressions at 80 chest compressions per min, treatment with active compression-decompression cardiopulmonary resuscitation at 80 chest compressions/min combined with augmentation of negative intrathoracic pressure would lower intracranial pressure and increase cerebral perfusion, thereby improving neurologically intact survival rates following prolonged untreated cardiac arrest.</AbstractText>Prospective, randomized animal study.</AbstractText>Animal laboratory facilities.</AbstractText>A total of 26 female farm pigs in two different protocols (n = 17 and n = 9).</AbstractText><AbstractText Label="INTERVENTIONS, MEASUREMENTS, AND MAIN RESULTS" NlmCategory="RESULTS">Seventeen pigs were subjected to 8.5 mins of untreated ventricular fibrillation and prospectively randomized to cardiopulmonary resuscitation at 80 chest compressions/min or active compression-decompression cardiopulmonary resuscitation at 80 chest compressions/min plus an impedance threshold device. Coronary perfusion pressures (29.5 ± 2.7 mm Hg vs. 22.4 ± 1.6 mm Hg, p = .03), carotid blood flow (44.0 ± 12.2 vs. 30.9 ± 10.4, p = .03), and 24-hr neurological survival (88% vs. 22%, p = .015) were higher with active compression-decompression cardiopulmonary resuscitation + an impedance threshold device. Cerebral perfusion pressures, measured in nine additional pigs, were improved with active compression-decompression cardiopulmonary resuscitation + an impedance threshold device (21.9 ± 1.2 mm Hg vs. 8.9 ± 0.8 mm Hg, p < .0001). With active compression-decompression cardiopulmonary resuscitation + impedance threshold device, mean diastolic intracranial pressure during decompression was lower (12.2 ± 0.2 mm Hg vs. 16.6 ± 1.2 mm Hg, p = .02) and the downward slope of the decompression phase intracranial pressure curve was steeper (-60.3 ± 12.9 mm Hg vs. -46.7 ± 11.1 mm Hg/sec, p < .001).</AbstractText>Active compression-decompression cardiopulmonary resuscitation + an impedance threshold device increased cerebral perfusion pressures and lowered diastolic intracranial pressure and intracranial pressure rate during the decompression phase. These mechanisms may underlie the observed increase in cerebral perfusion pressure, carotid blood flow, and survival rates with favorable neurologic outcomes in this pig model of cardiac arrest.</AbstractText> |
14,228 | [Sudden death caused by a less lethal weapon chest-wall injury (Commotio cordis)]. | Less lethal weapons, like Flashball, are more and more used since 1995 in law enforcement, even by the local police to neutralize combative individuals and to disperse riot crowds. This gun fires large rubber bullets and has been incriminated many times in cases of face injuries with functional consequences. In this case report, we mention a case of sudden death from cardiac arrest due to low energy chest wall impact of a rubber bullet shot with the Flashball. Commotio cordis is potentialized by a lethal set of three including, a certain impact velocity, an exact location of the hit over the cardiac silhouette, and a precise timing 15 m/s prior to the peak of the T-wave. This case report highlights the fact that such impacts can cause significant injury to internal organs, in particular circonstances, implying the necessity of a raising awareness of the medical staff, in ordre to not underestimate the severity of such injuries. |
14,229 | Documentation of impaired coronary blood flow by TIMI frame count method in patients with atrial fibrillation. | Atrial fibrillation (AF) is associated with impaired coronary flow and diminished myocardial perfusion. In the present study we aimed to evaluate coronary blood flow by means of Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) in patients with AF in the absence of obstructive coronary artery disease (CAD).</AbstractText>This prospective study initially enrolled 166 patients with AF and 332 age- and gender-matched control subjects without AF. After diagnostic coronary angiography, TFC was assessed in the participants without obstructive CAD, with 146 in the AF group and 150 in the control group.</AbstractText>The TFC for three major coronary arteries and the mean TFC were found to be significantly higher in AF patients compared to control subjects (34.1 ± 10.4 vs. 25.0 ± 10.4, 31.8 ± 9.7 vs. 23.7 ± 9.1, and 32.3 ± 9.5 vs. 24.1 ± 8.4 for each artery and 32.8 ± 9.2 vs. 24.3 ± 8.9 for mean TFC, p<0.001 for all comparisons). The mean TFC was 28.8 ± 7.9 in patients with paroxysmal AF, 33.7 ± 8.7 in those with persistent AF, and 39.0 ± 8.8 in those with long-standing or permanent AF (p<0.01 for all comparisons). After multivariate analysis, we found that the presence of AF remains to be independently associated with mean TFC. In AF group, baseline heart rate, left ventricular ejection fraction, AF duration and left atrium diameter were found to be independently associated with mean TFC.</AbstractText>Patients with atrial fibrillation in the absence of obstructive coronary artery disease have significantly higher TIMI frame counts for all three coronary vessels, indicating impaired coronary blood flow, compared to the control subjects without atrial fibrillation.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,230 | A mechanical characterization of the porcine atria at the healthy stage and after ventricular tachypacing. | Atrial fibrillation (AF) is a cardiac arrhythmia that highly increases the risk of stroke and is associated with significant but still unexplored changes in the mechanical behavior of the tissue. Planar biaxial tests were performed on tissue specimens from pigs at the healthy stage and after ventricular tachypacing (VTP), a procedure applied to reproduce the relevant features of AF. The local arrangement of the fiber bundles in the tissue was investigated on specimens from rabbit atria by means of circularly polarized light. Based on this, mechanical data were fitted to two anisotropic constitutive relationships, including a four-parameter Fung-type model and a microstructurally-motivated model. Accounting for the fiber-induced anisotropy brought average R(2) = 0.807 for the microstructurally-motivated model and average R(2) = 0.949 for the Fung model. Validation of the fitted constitutive relationships was performed by means of FEM simulations coupled to FORTRAN routines. The performances of the two material models in predicting the second Piola-Kirchhoff stress were comparable, with average errors <3.1%. However, the Fung model outperformed the other in the prediction of the Green-Lagrange strain, with 9.2% maximum average error. To increase model generality, a proper averaging procedure accounting for nonlinearities was used to obtain average material parameters. In general, a stiffer behavior after VTP was noted. |
14,231 | Cardiovascular disease in women: implications for improving health outcomes. | To collate data on women and cardiovascular disease in Australia and globally to inform public health campaigns and health care interventions.</AbstractText>Literature review.</AbstractText>Women with acute coronary syndromes show consistently poorer outcomes than men, independent of comorbidity and management, despite less anatomical obstruction of coronary arteries and relatively preserved left ventricular function. Higher mortality and complication rates are best documented amongst younger women and those with ST-segment-elevation myocardial infarction. Sex differences in atherogenesis and cardiovascular adaptation have been hypothesised, but not proven. Atrial fibrillation carries a relatively greater risk of stroke in women than in men, and anticoagulation therapy is associated with higher risk of bleeding complications. The degree of risk conferred by single cardiovascular risk factors and combinations of risk factors may differ between the sexes, and marked postmenopausal changes are seen in some risk factors. Sociocultural factors, delays in seeking care and differences in self-management behaviours may contribute to poorer outcomes in women. Differences in clinical management for women, including higher rates of misdiagnosis and less aggressive treatment, have been reported, but there is a lack of evidence to determine their effects on outcomes, especially in angina. Although enrolment of women in randomised clinical trials has increased since the 1970s, women remain underrepresented in cardiovascular clinical trials.</AbstractText>Improvement in the prevention and management of CVD in women will require a deeper understanding of women's needs by the community, health care professionals, researchers and government.</AbstractText> |
14,232 | Impact of early intravenous epinephrine administration on outcomes following out-of-hospital cardiac arrest. | The effectiveness of epinephrine administration for cardiac arrests has been shown in animal models, but the clinical effect is still controversial.</AbstractText>A prospective, population-based, observational study in Osaka involved consecutive out-of-hospital cardiac arrest (OHCA) patients from January 2007 through December 2009. We evaluated the outcomes among adult non-traumatic bystander-witnessed OHCA patients for whom the local protocol directed the emergency medical service personnel to administer epinephrine. After stratifying by first documented cardiac rhythm, outcomes were compared among the following groups: non-administration, ≤10, 11-20 and ≥21 min as the time from emergency call to epinephrine administration. A total of 3,161 patients were eligible for our analyses, among whom 1,013 (32.0%) actually received epinephrine. The epinephrine group had a significantly lower rate of neurologically intact 1-month survival than the non-epinephrine group (4.1% vs. 6.1%, P=0.028). In cases of ventricular fibrillation (VF) arrest, patients in the early epinephrine group who received epinephrine administration within 10 min had a significantly higher rate of neurologically intact 1-month survival compared with the non-epinephrine group (66.7% vs. 24.9%), though other epinephrine groups did not. In cases of non-VF arrest, the rate of neurologically intact 1-month survival was low, irrespective of epinephrine administration.</AbstractText>The effectiveness of epinephrine after OHCA depends on the time of administration. When epinephrine is administered in the early phase, there is an improvement in neurological outcome from OHCA with VF.</AbstractText> |
14,233 | Importance of ventricular tachycardia storms not terminated by implantable cardioverter defibrillators shocks in patients with CASQ2 associated catecholaminergic polymorphic ventricular tachycardia. | In this study, the clinical and implantable cardioverter-defibrillator (ICD)-related follow-up of patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) with homogenous missense mutations in CASQ2 was summarized. Patients were followed in a pediatric cardiology clinic and an ICD clinic. All patients were treated with high-dose β blockers. ICDs were recommended for patients who remained symptomatic despite medical treatment. Twenty-seven patients were followed for 1 to 15 years (median 9). Twenty patients (74%) were symptomatic at diagnosis; 13 (65%) remained symptomatic after treatment with high-dose β blockers and thus were advised to receive ICDs. Eight of these patients refused ICDs, and eventually 6 (75%) died suddenly. Four of the 5 patients who received ICDs had ventricular tachycardia storms treated but not terminated by recurrent ICD shocks. These ventricular tachycardia storms (2 episodes in 2 patients and 1 episode in 2 patient) terminated spontaneously after finishing the programmed ICD shocks, without degeneration to ventricular fibrillation. None of the patients who received ICDs died. In conclusion, patients with CASQ2-associated CPVT should be recommended to receive ICDs to prevent sudden death when medical therapy is not effective. These patients may have recurrent ventricular tachycardia storms treated but not terminated by recurrent ICD shocks, without degeneration to ventricular fibrillation. |
14,234 | Atrial fibrillation management, outcomes and predictors of stable disease in daily practice: prospective non-interventional study. | We aimed to describe the current management of patients with atrial fibrillation (AF) by cardiologists, and to identify predicting factors for a stable disease course.</AbstractText>2753 consecutive patients with ECG-confirmed AF in the previous 12 months were documented in a 1-year observational (non-interventional) study from 616 centers. Stable disease was defined as having neither AF related intervention nor change in antiarrhythmic therapy in the previous 12 months. Stepwise selection of parameters for multivariate regression was used to identify factors for stable AF.</AbstractText>At baseline, paroxysmal AF was reported in 33.5%, persistent in 26.7%, and permanent in 39.7%; rate control alone was the prevailing antiarrhythmic strategy (64.2%). Drugs for thromboembolic prevention were administered in 93.8%, with a clear predominance of oral anticoagulants (OAC), alone or in combination with antiplatelet drugs. Electrical or pharmacological conversions were reported in 23.6%. A total of 96 (3.5%) patients in the total cohort experienced stroke, 72 patients (2.6%) TIA, and 24 (0.9%) arterial embolism. 26% were hospitalized during follow-up (0.4 events per patient), and 9.4% developed incident heart failure (42% prevalence at follow-up). The rate of stable patients was 43.4%. In the multivariate model male gender, history of stroke, and permanent (vs. persistent) AF were associated with stable disease. Conversely, the factors chronic heart failure, impaired left ventricular function, rhythm-control (vs. other), OAC and antiplatelet therapy were significantly correlated with unstable disease.</AbstractText>The relatively low proportion of stable patients and in particular, the high hospitalization and stroke rate indicate difficulties in everyday management of patients with AF.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,235 | Early surgery for asymptomatic mitral regurgitation: importance of atrial fibrillation. | It remains controversial whether early mitral valve (MV) repair should be performed for severe degenerative mitral regurgitation (MR) without symptoms, left ventricular (LV) dilatation or dysfunction, atrial fibrillation (AF) or pulmonary artery hypertension (PH), even at experienced surgical centers. The study aim was to reconsider the optimal timing of intervention for asymptomatic patients with severe degenerative MR at experienced surgical centers.</AbstractText>Clinical outcomes were reviewed retrospectively for 298 consecutive asymptomatic patients (mean age 57 +/- 12 years) who underwent MV surgery for degenerative MR. The patients were allocated to two groups based on the following comorbid conditions: LVEF < or = 60%, LV end-systolic dimension 40 mm, AF, and PH. Group A comprised 122 patients with none of these conditions, while group B comprised 176 patients with any one of the conditions. The clinical outcomes were compared between the two groups at a mean of 7.0 +/- 4.5 years after surgery.</AbstractText>MV repair had been attempted in all patients, with a success rate of 100%. At 10 years, survival among group B patients was poorer than in group A (93% and 81%, respectively; p = 0.02), and there was a lower freedom from valve-related events (89% and 71%, respectively; p < 0.01). The independent predictors of valve-related events were preoperative AF (hazard ratio 3.34; p < 0.001) and age > 60 years (hazard ratio 2.50; p < 0.01).</AbstractText>Early MV repair is a reasonable option in asymptomatic patients, while preoperative AF may be a more appropriate predictor of an adverse outcome than LV function, as is currently recommended.</AbstractText> |
14,236 | Impact of changes in resuscitation practice on survival and neurological outcome after out-of-hospital cardiac arrest resulting from nonshockable arrhythmias. | Out-of-hospital cardiac arrest (OHCA) claims millions of lives worldwide each year. OHCA survival from shockable arrhythmias (ventricular fibrillation/ tachycardia) improved in several communities after implementation of American Heart Association resuscitation guidelines that eliminated "stacked" shocks and emphasized chest compressions. "Nonshockable" rhythms are now the predominant presentation of OHCA; the benefit of such treatments on nonshockable rhythms is uncertain.</AbstractText>We studied 3960 patients with nontraumatic OHCA from nonshockable initial rhythms treated by prehospital providers in King County, Washington, over a 10-year period. Outcomes during a 5-year intervention period after adoption of new resuscitation guidelines were compared with the previous 5-year historical control period. The primary outcome was 1-year survival. Patient demographics and resuscitation characteristics were similar between the control (n=1774) and intervention (n=2186) groups, among whom 471 of 1774 patients (27%) versus 742 of 2186 patients (34%), respectively, achieved return of spontaneous circulation; 82 (4.6%) versus 149 (6.8%) were discharged from hospital, 60 (3.4%) versus 112 (5.1%) with favorable neurological outcome; 73 (4.1%) versus 135 (6.2%) survived 1 month; and 48 (2.7%) versus 106 patients (4.9%) survived 1 year (all P≤0.005). After adjustment for potential confounders, the intervention period was associated with an improved odds of 1.50 (95% confidence interval, 1.29-1.74) for return of spontaneous circulation, 1.53 (95% confidence interval, 1.14-2.05) for hospital survival, 1.56 (95% confidence interval, 1.11-2.18) for favorable neurological status, 1.54 (95% confidence interval, 1.14-2.10) for 1-month survival, and 1.85 (95% confidence interval, 1.29-2.66) for 1-year survival.</AbstractText>Outcomes from OHCA resulting from nonshockable rhythms, although poor by comparison with shockable rhythm presentations, improved significantly after implementation of resuscitation guideline changes, suggesting their potential to benefit all presentations of OHCA.</AbstractText> |
14,237 | Tissue Doppler imaging-derived myocardial acceleration during isovolumetric contraction predicts pulmonary capillary wedge pressure in patients with reduced ejection fraction. | Tissue Doppler imaging-obtained isovolumetric myocardial acceleration (IVA) is load independent, reportedly predicts systolic functions, and correlates with exercise capacity in patients with reduced ejection fraction (EF). We hypothesized that IVA correlates with the pulmonary capillary wedge pressure (PCWP) in patients with reduced EF.</AbstractText>Of 113 patients, correlations between PCWP and IVA were done for all patients, 48 patients with EF ≥55%, and 65 patients with EF <55%. Results were compared to the correlation between PCWP and other echocardiographic predictors. IVA correlated moderately with PCWP in all patients (r=0.54, P<0.0001) and was comparable to the E/A and E/e' ratios. In patients with EF ≥55%, IVA lost correlation and the only predictor was the E/e' ratio (r=0.08, 0.58, P=0.58, <0.0001). In patients with EF <55%, IVA was better than E/A and E/e' (r=0.72, 0.61, 0.51, P<0.0001), especially for atrial fibrillation or when E/e' fell between 8 and 15. Furthermore, IVA >1.60 m/s(2) can predict PCWP ≥15 mmHg, with a sensitivity of 95%, specificity of 73%, and an area under the curve of 0.867 (P<0.0001).</AbstractText>IVA can predict PCWP in patients with reduced EF, and can be considered an alternative to the E/e' ratio for patients with atrial fibrillation or E/e' ratio between 8 and 15.</AbstractText> |
14,238 | Unrepaired tetralogy of fallot in an 85-year-old man. | Tetralogy of Fallot is the most common cyanotic congenital heart defect and accounts for about 5% of all congenital cardiopathies. The definitive treatment modality for tetralogy of Fallot is reparative surgery, which is recommended to be performed by the time of diagnosis. Without surgical repair, most patients would die during their childhood. In the past, survival data indicated that 66% of persons with tetralogy of Fallot not surgically treated lived until the age of 1, 49% lived until the age of 3, and 24% lived until the age of 10. We now present a rare case of a man with unrepaired tetralogy of Fallot who survived until the age of 85. He presented to our emergency room for dyspnea and palpitations due to a new-onset high-frequency atrial fibrillation and acute heart failure; transthoracic echocardiography showed the presence of tetralogy of Fallot. By consulting the scientific literature, we can say that this is the second patient who survived more than 80 years without surgical intervention. |
14,239 | Effect of dietary omega-3 polyunsaturated Fatty acids on heart rate and heart rate variability in animals susceptible or resistant to ventricular fibrillation. | The consumption of omega-3 polyunsaturated fatty acids (n-3 PUFAs) has been reported to reduce cardiac mortality following myocardial infarction as well as to decrease resting heart rate (HR) and increase HR variability (HRV). However, it has not been established whether n-3 PUFAs exhibit the same actions on HR and HRV in individuals known to be either susceptible or resistant to ventricular fibrillation (VF). Therefore, HR and HRV (high frequency and total R-R interval variability) were evaluated before and 3 months after n-3 PUFA treatment in dogs with healed myocardial infarction that were either susceptible (VF+, n = 31) or resistant (VF-, n = 31) to ventricular tachyarrhythmias induced by a 2-min coronary artery occlusion during the last minute of a submaximal exercise test. HR and HRV were evaluated at rest, during submaximal exercise and in response to acute myocardial ischemia at rest before and after either placebo (1 g/day, corn oil, VF+, n = 9; VF- n = 8) or n-3 PUFA (docosahexaenoic acid + eicosapentaenoic acid ethyl esters, 1-4 g/day, VF+, n = 22; VF-, n = 23) treatment for 3 months. The n-3 PUFA treatment elicited similar increases in red blood cell membrane, right atrial, and left ventricular n-3 PUFA levels in both the VF+ and VF- dogs. The n-3 PUFA treatment also provoked similar reductions in baseline HR and increases in baseline HRV in both groups that resulted in parallel shifts in the response to either exercise or acute myocardial ischemia (that is, the change in these variables induced by physiological challenges was not altered after n-3 PUFA treatment). These data demonstrate that dietary n-3 PUFA decreased HR and increased HRV to a similar extent in animals known to be prone to or resistant to malignant cardiac tachyarrhythmias. |
14,240 | Spontaneous coronary artery dissection in a young woman without risk factors. | Spontaneous coronary artery dissection is a very rare event and is more common in women than in men. Pregnancy and the early puerperium stage have been recognized as predisposing factors for this condition.</AbstractText>A 33-year-old woman presented to the Emergency Department (ED) with chest pain; the patient's electrocardiogram (ECG) showed an ST-segment elevation similar to that observed in ST-segment elevation myocardial infarction (STEMI). She experienced a ventricular fibrillation cardiac arrest when she was in the hospital and received resuscitation, after which she regained consciousness and showed spontaneous circulation. She underwent cardiac catheterization under the impression of spontaneous coronary artery dissection, and conservative therapy was chosen.</AbstractText>In this report, we have underlined the importance of considering coronary artery dissection in the differential diagnosis of young women who present to the ED with chest pain, an ECG with ST-segment elevation, and very few cardiac risk factors.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,241 | Pulmonary vein isolation for the treatment of drug-refractory atrial fibrillation in adults with congenital heart disease. | Atrial fibrillation (AF) is a common arrhythmia in adults with congenital heart disease (CHD). Long-term antiarrhythmic therapy (AAT) in these patients has significant shortcomings. The safety and efficacy of pulmonary vein antrum isolation (PVAI) for the treatment of AF in CHD is presently unknown.</AbstractText>We hypothesized that PVAI for AF in patients with CHD is effective and safe.</AbstractText>We reviewed a prospective cohort of 4315 patients (age ≥ 18) undergoing PVAI for drug refractory AF at a single institution and identified 36 consecutive patients with CHD (single ventricle physiology, tetralogy of Fallot, coarctation of the aorta, ventricular septal defects, atrial septal defects (ASD) and cardiomyopathy resulting from anomalous origin of the left main coronary from the pulmonary artery). A second cohort of 355 consecutive patients with noncongenital structural heart disease (NSHD) (coronary artery disease, valvular heart disease, ejection fraction <50%, or prior noncongenital cardiac surgery) undergoing PVAI during the same time period was used as a control. Success was defined as freedom from AF starting two months after PVAI in the absence AAT until the end of follow-up. Partial success was defined as freedom from AF in the presence of AAT until the end of follow-up. Combined success was defined as the sum of success and partial success. We compared the outcomes with the use of propensity-score matching in the overall cohort.</AbstractText>Patients with NSHD were older and had higher prevalence of hypertension (P < .01), diabetes (P < .01) and hyperlipidemia (P < .01). The most common CHD lesion was ASD (61%) and the most common NSHD lesion was valvular heart disease (57%). After one PVAI, success was achieved in 42% and 53% at 300 days in the CHD and NSHD groups respectively. Four-year success was achieved in 27% and 36% in the CHD and NSHD groups, respectively. There were no significant differences in the success rates between patients groups (P= .46), nor were there any differences in left atrial size or changes in ejection fraction after one or two PVAI in the respective groups. Complication rates between the CHD and NSHD groups were similar (15% vs. 11%, P= .42) except for a higher risk of vascular site complications in patients with CHD (8% vs. 1%, P < .05).</AbstractText>PVAI is an attractive treatment modality in drug refractory AF in CHD, with combined success rates in excess of 60%. The maintenance of sinus rhythm after PVAI in CHD appears similar to that of NSHD and warrants prospective validation.</AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
14,242 | Degenerating regenerating torsades de pointes. | Ventricular fibrillation (VF) commonly ends in death. Isolated case reports describe the uncommon occurrence of spontaneous termination of VF. Torsades de pointes (TdP), a peculiar form of polymorphic ventricular tachycardia associated with a prolonged QT interval on the surface electrocardiogram, most often spontaneously terminates and then returns to the underlying rhythm. Here, we present an unusual case of TdP degenerating into VF, reorganizing into TdP, and then spontaneously terminating. Our case suggests that the mechanisms underlying the maintenance of TdP and VF are not dissimilar. The precipitants to this event and the likely mechanisms operative are discussed. |
14,243 | Enhanced sensitivity of aged fibrotic hearts to angiotensin II- and hypokalemia-induced early afterdepolarization-mediated ventricular arrhythmias. | Unlike young hearts, aged hearts are highly susceptible to early afterdepolarization (EAD)-mediated ventricular fibrillation (VF). This differential may result from age-related structural remodeling (fibrosis) or electrical remodeling of ventricular myocytes or both. We used optical mapping and microelectrode recordings in Langendorff-perfused hearts and patch-clamp recordings in isolated ventricular myocytes from aged (24-26 mo) and young (3-4 mo) rats to assess susceptibility to EADs and VF during either oxidative stress with ANG II (2 μM) or ionic stress with hypokalemia (2.7 mM). ANG II caused EAD-mediated VF in 16 of 19 aged hearts (83%) after 32 ± 7 min but in 0 of 9 young hearts (0%). ANG II-mediated VF was suppressed with KN-93 (Ca(2+)/calmodulin-dependent kinase inhibitor) and the reducing agent N-acetylcysteine. Hypokalemia caused EAD-mediated VF in 11 of 11 aged hearts (100%) after 7.4 ± 0.4 min. In 14 young hearts, however, VF did not occur in 6 hearts (43%) or was delayed in onset (31 ± 22 min, P < 0.05) in 8 hearts (57%). In patch-clamped myocytes, ANG II and hypokalemia (n = 6) induced EADs and triggered activity in both age groups (P = not significant) at a cycle length of >0.5 s. When myocytes of either age group were coupled to a virtual fibroblast using the dynamic patch-clamp technique, EADs arose in both groups at a cycle length of <0.5 s. Aged ventricles had significantly greater fibrosis and reduced connexin43 gap junction density compared with young hearts. The lack of differential age-related sensitivity at the single cell level in EAD susceptibility indicates that increased ventricular fibrosis in the aged heart plays a key role in increasing vulnerability to VF induced by oxidative and ionic stress. |
14,244 | Contractile parameters and occurrence of alternans in isolated rat myocardium at supra-physiological stimulation frequency. | The cardiac refractory period prevents the heart from tetanic activation that is typically used in noncardiac striated muscle tissue. To what extent the refractory period prevents successive action potentials to activate the excitation-contraction coupling process and contractile machinery at supra-physiological rates, such as those present during ventricular fibrillation, is unknown. Using multicellular trabeculae isolated from rat hearts, we studied amplitude and kinetics of contraction at rates well above the normal in vivo rat heart range. We show that even at twice the maximal heart rate of the rat, little or no mechanical instability is observed; twitch contractions are at steady state, albeit with an elevated active diastolic force. Although the amplitude of contraction increased within in vivo heart rates (positive force-frequency response), at frequencies beyond the maximal heart rate (10-30 Hz) a steady decline of contractile amplitude is observed. Not until 30 Hz do the majority of the isolated muscle preparations show mechanical alternans, where strong and weak beats alternate. Interestingly, unlike striated limb skeletal muscle, fusing of twitch contractions did not cause a continuous increase in peak force: at frequencies of 10 Hz and above, systolic force declines with relatively little elevation in diastolic force. Contractile kinetics continued to accelerate, from 1 Hz up to 30 Hz, whereas the relative speed of contraction and relaxation remained closely coupled, reflected by a singular linear relationship between the maximal and minimal derivative of force (dF/dt). We conclude that cardiac muscle can produce mechanically stable steady-state contractions at supra-physiological pacing rates, while these contractions continue to decline in amplitude and increase in diastolic force past maximal heart rate. |
14,245 | Role of KATP channel in electrical depression and asystole during long-duration ventricular fibrillation in ex vivo canine heart.<Pagination><StartPage>H2396</StartPage><EndPage>H2409</EndPage><MedlinePgn>H2396-409</MedlinePgn></Pagination><ELocationID EIdType="doi" ValidYN="Y">10.1152/ajpheart.00752.2011</ELocationID><Abstract><AbstractText>Long-duration ventricular fibrillation (LDVF) in the globally ischemic heart is characterized by transmurally heterogeneous decline in ventricular fibrillation rate (VFR), emergence of inexcitable regions, and eventual global asystole. Rapid loss of both local and global excitability is detrimental to successful defibrillation and resuscitation during cardiac arrest. We sought to assess the role of the ATP-sensitive potassium current (I(KATP)) in the timing and spatial pattern of electrical depression during LDVF in a structurally normal canine heart. We analyzed endo-, mid-, and epicardial unipolar electrograms and epicardial optical recordings in the left ventricle of isolated canine hearts during 10 min of LDVF in the absence (control) and presence of an I(KATP) blocker glybenclamide (60 μM). In all myocardial layers, average VFR was the same or higher in glybenclamide-treated than in control hearts. The difference increased with time of LDVF and was overall significant in all layers (P < 0.05). However, glybenclamide did not significantly affect the transmural VFR gradient. In epicardial optical recordings, glybenclamide shortened diastolic intervals, prolonged action potential duration, and decreased the percentage of inexcitable area (all differences P < 0.001). During 10 min of LDVF, asystole occurred in 55.6% of control and none of glybenclamide-treated hearts (P < 0.05). In three hearts paced after the onset of asystole, there was no response to LV epicardial or atrial pacing. In structurally normal canine hearts, I(KATP) opening during LDVF is a major factor in the onset of local and global inexcitability, whereas it has a limited role in overall deceleration of VFR and the transmural VFR gradient.</AbstractText></Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Taylor</LastName><ForeName>Tyson G</ForeName><Initials>TG</Initials><AffiliationInfo><Affiliation>Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, 84112-5000, USA.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Venable</LastName><ForeName>Paul W</ForeName><Initials>PW</Initials></Author><Author ValidYN="Y"><LastName>Shibayama</LastName><ForeName>Junko</ForeName><Initials>J</Initials></Author><Author ValidYN="Y"><LastName>Warren</LastName><ForeName>Mark</ForeName><Initials>M</Initials></Author><Author ValidYN="Y"><LastName>Zaitsev</LastName><ForeName>Alexey V</ForeName><Initials>AV</Initials></Author></AuthorList><Language>eng</Language><GrantList CompleteYN="Y"><Grant><GrantID>R01 HL088444</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>1R01-HL-103877</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>5R01-HL-088444</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>1F32-HL-097576</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant></GrantList><PublicationTypeList><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D052061">Research Support, N.I.H., Extramural</PublicationType><PublicationType UI="D013485">Research Support, Non-U.S. Gov't</PublicationType></PublicationTypeList><ArticleDate DateType="Electronic"><Year>2012</Year><Month>03</Month><Day>30</Day></ArticleDate></Article><MedlineJournalInfo><Country>United States</Country><MedlineTA>Am J Physiol Heart Circ Physiol</MedlineTA><NlmUniqueID>100901228</NlmUniqueID><ISSNLinking>0363-6135</ISSNLinking></MedlineJournalInfo><ChemicalList><Chemical><RegistryNumber>0</RegistryNumber><NameOfSubstance UI="D054086">KATP Channels</NameOfSubstance></Chemical><Chemical><RegistryNumber>SX6K58TVWC</RegistryNumber><NameOfSubstance UI="D005905">Glyburide</NameOfSubstance></Chemical></ChemicalList><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D000818" MajorTopicYN="N">Animals</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004285" MajorTopicYN="N">Dogs</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004562" MajorTopicYN="Y">Electrocardiography</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005260" MajorTopicYN="N">Female</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005905" MajorTopicYN="N">Glyburide</DescriptorName><QualifierName UI="Q000494" MajorTopicYN="N">pharmacology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D006323" MajorTopicYN="N">Heart Arrest</DescriptorName><QualifierName UI="Q000503" MajorTopicYN="Y">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D054086" MajorTopicYN="N">KATP Channels</DescriptorName><QualifierName UI="Q000037" MajorTopicYN="N">antagonists & inhibitors</QualifierName><QualifierName UI="Q000187" MajorTopicYN="N">drug effects</QualifierName><QualifierName UI="Q000502" MajorTopicYN="Y">physiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D008297" MajorTopicYN="N">Male</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D023421" MajorTopicYN="N">Models, Animal</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D013997" MajorTopicYN="N">Time Factors</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D014693" MajorTopicYN="N">Ventricular Fibrillation</DescriptorName><QualifierName UI="Q000503" MajorTopicYN="Y">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D056969" MajorTopicYN="N">Voltage-Sensitive Dye Imaging</DescriptorName></MeshHeading></MeshHeadingList></MedlineCitation><PubmedData><History><PubMedPubDate PubStatus="entrez"><Year>2012</Year><Month>4</Month><Day>3</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="pubmed"><Year>2012</Year><Month>4</Month><Day>3</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="medline"><Year>2012</Year><Month>9</Month><Day>13</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate></History><PublicationStatus>ppublish</PublicationStatus><ArticleIdList><ArticleId IdType="pubmed">22467302</ArticleId><ArticleId IdType="pmc">PMC3378304</ArticleId><ArticleId IdType="doi">10.1152/ajpheart.00752.2011</ArticleId><ArticleId IdType="pii">ajpheart.00752.2011</ArticleId></ArticleIdList><ReferenceList><Reference><Citation>Akar FG, Aon MA, Tomaselli GF, O'Rourke B. 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Rapid loss of both local and global excitability is detrimental to successful defibrillation and resuscitation during cardiac arrest. We sought to assess the role of the ATP-sensitive potassium current (I(KATP)) in the timing and spatial pattern of electrical depression during LDVF in a structurally normal canine heart. We analyzed endo-, mid-, and epicardial unipolar electrograms and epicardial optical recordings in the left ventricle of isolated canine hearts during 10 min of LDVF in the absence (control) and presence of an I(KATP) blocker glybenclamide (60 μM). In all myocardial layers, average VFR was the same or higher in glybenclamide-treated than in control hearts. The difference increased with time of LDVF and was overall significant in all layers (P < 0.05). However, glybenclamide did not significantly affect the transmural VFR gradient. In epicardial optical recordings, glybenclamide shortened diastolic intervals, prolonged action potential duration, and decreased the percentage of inexcitable area (all differences P < 0.001). During 10 min of LDVF, asystole occurred in 55.6% of control and none of glybenclamide-treated hearts (P < 0.05). In three hearts paced after the onset of asystole, there was no response to LV epicardial or atrial pacing. In structurally normal canine hearts, I(KATP) opening during LDVF is a major factor in the onset of local and global inexcitability, whereas it has a limited role in overall deceleration of VFR and the transmural VFR gradient.</Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Taylor</LastName><ForeName>Tyson G</ForeName><Initials>TG</Initials><AffiliationInfo><Affiliation>Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, 84112-5000, USA.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Venable</LastName><ForeName>Paul W</ForeName><Initials>PW</Initials></Author><Author ValidYN="Y"><LastName>Shibayama</LastName><ForeName>Junko</ForeName><Initials>J</Initials></Author><Author ValidYN="Y"><LastName>Warren</LastName><ForeName>Mark</ForeName><Initials>M</Initials></Author><Author ValidYN="Y"><LastName>Zaitsev</LastName><ForeName>Alexey V</ForeName><Initials>AV</Initials></Author></AuthorList><Language>eng</Language><GrantList CompleteYN="Y"><Grant><GrantID>R01 HL088444</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>1R01-HL-103877</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>5R01-HL-088444</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant><Grant><GrantID>1F32-HL-097576</GrantID><Acronym>HL</Acronym><Agency>NHLBI NIH HHS</Agency><Country>United States</Country></Grant></GrantList><PublicationTypeList><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D052061">Research Support, N.I.H., Extramural</PublicationType><PublicationType UI="D013485">Research Support, Non-U.S. Gov't</PublicationType></PublicationTypeList><ArticleDate DateType="Electronic"><Year>2012</Year><Month>03</Month><Day>30</Day></ArticleDate></Article><MedlineJournalInfo><Country>United States</Country><MedlineTA>Am J Physiol Heart Circ Physiol</MedlineTA><NlmUniqueID>100901228</NlmUniqueID><ISSNLinking>0363-6135</ISSNLinking></MedlineJournalInfo><ChemicalList><Chemical><RegistryNumber>0</RegistryNumber><NameOfSubstance UI="D054086">KATP Channels</NameOfSubstance></Chemical><Chemical><RegistryNumber>SX6K58TVWC</RegistryNumber><NameOfSubstance UI="D005905">Glyburide</NameOfSubstance></Chemical></ChemicalList><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D000818" MajorTopicYN="N">Animals</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004285" MajorTopicYN="N">Dogs</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D004562" MajorTopicYN="Y">Electrocardiography</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005260" MajorTopicYN="N">Female</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005905" MajorTopicYN="N">Glyburide</DescriptorName><QualifierName UI="Q000494" MajorTopicYN="N">pharmacology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D006323" MajorTopicYN="N">Heart Arrest</DescriptorName><QualifierName UI="Q000503" MajorTopicYN="Y">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D054086" MajorTopicYN="N">KATP Channels</DescriptorName><QualifierName UI="Q000037" MajorTopicYN="N">antagonists & inhibitors</QualifierName><QualifierName UI="Q000187" MajorTopicYN="N">drug effects</QualifierName><QualifierName UI="Q000502" MajorTopicYN="Y">physiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D008297" MajorTopicYN="N">Male</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D023421" MajorTopicYN="N">Models, Animal</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D013997" MajorTopicYN="N">Time Factors</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D014693" MajorTopicYN="N">Ventricular Fibrillation</DescriptorName><QualifierName UI="Q000503" MajorTopicYN="Y">physiopathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D056969" MajorTopicYN="N">Voltage-Sensitive Dye Imaging</DescriptorName></MeshHeading></MeshHeadingList></MedlineCitation><PubmedData><History><PubMedPubDate PubStatus="entrez"><Year>2012</Year><Month>4</Month><Day>3</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="pubmed"><Year>2012</Year><Month>4</Month><Day>3</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="medline"><Year>2012</Year><Month>9</Month><Day>13</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate></History><PublicationStatus>ppublish</PublicationStatus><ArticleIdList><ArticleId IdType="pubmed">22467302</ArticleId><ArticleId IdType="pmc">PMC3378304</ArticleId><ArticleId IdType="doi">10.1152/ajpheart.00752.2011</ArticleId><ArticleId IdType="pii">ajpheart.00752.2011</ArticleId></ArticleIdList><ReferenceList><Reference><Citation>Akar FG, Aon MA, Tomaselli GF, O'Rourke B. 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Circ Res 92: 546–553, 2003</Citation><ArticleIdList><ArticleId IdType="pubmed">12600877</ArticleId></ArticleIdList></Reference></ReferenceList></PubmedData></PubmedArticle><PubmedArticle><MedlineCitation Status="MEDLINE" Owner="NLM"><PMID Version="1">22466537</PMID><DateCompleted><Year>2012</Year><Month>08</Month><Day>01</Day></DateCompleted><DateRevised><Year>2015</Year><Month>11</Month><Day>19</Day></DateRevised><Article PubModel="Print"><Journal><ISSN IssnType="Print">1512-0112</ISSN><JournalIssue CitedMedium="Internet"><Issue>203</Issue><PubDate><Year>2012</Year><Month>Feb</Month></PubDate></JournalIssue><Title>Georgian medical news</Title><ISOAbbreviation>Georgian Med News</ISOAbbreviation></Journal><ArticleTitle>Reproducibility and diagnostic value of E100 event recorder for patients with complains on heart arrhythmias and no changes on multiple routine ECGs and 24-hour holter monitoring.</ArticleTitle><Pagination><StartPage>29</StartPage><EndPage>33</EndPage><MedlinePgn>29-33</MedlinePgn></Pagination><Abstract>Aim of the study was to assess reproducibility and diagnostic value of E100 event recorder for patients with complains on heart arrhythmias and no abnormalities on multiple routine ECGs and/or 24-hour Holter ECG monitoring and the second one, an assessment of adherence and attitude of patients to the E100 event recorder, dependent on the results of self- assessment questionnaires. 24 patients with complains on heart arrhythmias were included in the study. All the patients were provided with the REKA E100 event monitors for 5 ± 2 days and self-assessment questionnaires to assess level of adherence and attitude of patients to the E100 event recorder. E100 event recorders revealed junctional rhythm (n=2), AV nodal reentrant tachycardia (n=2), extrasystolic arrhythmias (n=10), atrial fibrillation (n=2), WPW syndrome (n=4), ventricular tachycardia (n=1), sinus tachycardia (n=7) and complete AV block (n=1). Majority of patients consider device as easy to use, comfortable and safe. In comparison with multiple routine ECGs and 24-hour Holter ECG monitoring, E100 event recorders showed higher reproducibility and efficacy for detecting and interpreting heart arrhythmias. |
14,246 | Impairment of carotid artery blood flow by supraglottic airway use in a swine model of cardiac arrest. | Supraglottic airway devices (SGDs) are often used as an alternative to endotracheal tube (ETT) during cardiopulmonary resuscitation (CPR). SGDs can be inserted 'blindly' and rapidly, without stopping compressions. These devices utilize pressurized balloons to direct air to the trachea and prevent esophagus insufflation. We hypothesize that the use of a SGD will compress the carotid artery and decrease carotid blood flow (CBF) during CPR in pigs.</AbstractText>Ventricular fibrillation (VF) was induced in 9 female pigs (32 ± 1 kg) followed by 4 min without compressions. CPR was then performed continuously for 3-6-min intervals. During each interval, an ETT was used for the first 3 min, followed by 3 min of each SGD (King LTS-D™, LMA Flexible™, Combitube™) in a random order. The primary endpoint was mean CBF (ml/min). Statistical comparisons among the 4 airway devices were performed by Wilcoxon Rank test. Post mortem carotid arteriographies were performed with SGDs in place.</AbstractText>CBF (median ml/min; 25/75 percentile) was significantly lower with each SGD [King (10; 6/41), LMA (10; 4/39), and Combitube (5; -0.4/15)] versus ETT (21; 14/46) (p<0.05 for each SGD compared with ETT). Arteriograms showed that with each SGD there was compression of the internal and external carotid vessels.</AbstractText>The use of 3 different SGDs during CPR significantly decreased CBF in a porcine model of cardiac arrest. While the current study is limited to pigs, the findings suggest that further research on the effects of SGD use in humans and the effects on carotid artery blood flow is warranted.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,247 | Breathing during cardiac arrest following exercise: a new function of the respiratory system? | We have found in four sheep that, following a muscular exercise, minute ventilation is maintained for 34-131 s during a cardiac arrest (CA), at a magnitude (from 28.2 and 54.7 l min(-1)) similar to the level of ventilation (and thus proportional to the metabolic rate) preceding the period of asystole. Breathing was maintained despite the lack of pulmonary blood flow and the cessation of the muscle contractions, leading to a dramatic reduction in alveolar FCO(2) (1.9 ± 1%). Secondly, swings in arterial blood pressure (ABP) were observed (pulse pressure of 31 ± 3 Torr) in phase with breathing movements in place of the cardiac activity. This "protective" response, deprived from any role in blood gas homeostasis, as circulation is virtually abolished, is not predictable from the traditional respiratory control feedback systems thought to be involved in exercise. We are presenting the view that this response, dissociated from the pulmonary gas exchanges, is the expression of a rudimentary defense mechanism aimed at limiting the consequences of an acute failure of the cardiac pump by the thoraco-abdominal pump. |
14,248 | Sympathetic innervation of the anterior left ventricular wall by the right and left stellate ganglia. | The sympathetic nervous system is thought to play a role in the genesis of ventricular tachyarrhythmias (VT). Left and added right cardiac sympathectomy have been shown to reduce the burden of arrhythmias in the setting of a VT storm. However, the contribution of the right stellate ganglion (RSG) and the left stellate ganglion (LSG) to the innervation of the anterior left ventricular (LV) wall is not well understood.</AbstractText>To evaluate the innervation of the anterior LV wall by the LSG and the RSG.</AbstractText>The heart and stellate ganglia were exposed via sternotomy in pigs with normal hearts (n = 8). A 20-electrode catheter was placed on the anterior LV wall to record activation recovery interval (ARI), a surrogate measure of action potential duration. A microdialysis catheter was inserted in a similar location to sample interstitial norepinephrine (NE) content. ARI and NE measurements were recorded at baseline and during LSG and RSG stimulation.</AbstractText>LSG stimulation shortened ARI by 17.1% ± 10.5% (mean ± standard error), while RSG stimulation shortened ARI by 42.1% ± 15.7%, P = .04 (LSG vs RSG). LSG stimulation increased interstitial NE levels by 200% ± 65%, while RSG stimulation increased the NE content by 260% ± 40% (P = .012). LSG stimulation increased dispersion in ARI from 376.0 ± 83.7 ms(2) to 1242.5 ± 566 ms(2) (P = .03) and caused ventricular fibrillation in 2 pigs. During RSG stimulation, dispersion increased from 419 ± 65.8 to 474.8 ± 81 ms(2) (P = .4).</AbstractText>Both the LSG and the RSG provide significant innervation to the anterior LV wall as demonstrated by both ARI shortening and NE concentrations. LSG stimulation significantly increases ARI dispersion. This study provides mechanistic insight into the beneficial effects of left sympathectomy and the additional role of right sympathectomy in reducing arrhythmias in patients with anterior myocardial scars and VT storm.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,249 | Fate of patients with prehospital resuscitation for ST-elevation myocardial infarction and a high rate of early reperfusion therapy (results from the PREMIR [Prehospital Myocardial Infarction Registry]). | Patients with acute ST-segment elevation myocardial infarction (STEMI) needing prehospital cardiopulmonary resuscitation (CPR) have a very high adverse-event rate. However, little is known about the fate of these patients and predictors of mortality in the era of early reperfusion therapy. From March 2003 through December 2004, 2,317 patients with prehospital diagnosed STEMI were enrolled in the Prehospital Myocardial Infarction Registry. One hundred ninety patients (8.2%) underwent prehospital CPR and were included in our analysis. Overall 90% of patients were treated with early reperfusion therapy, 56.3% received prehospital thrombolysis and 1/2 of these patients received early percutaneous coronary intervention after thrombolysis, 28.4% of patients were treated with primary percutaneous coronary intervention, and 5.3% received in-hospital thrombolysis. Total mortality was 40.0%. The highest mortality was seen in patients with asystole (63%) or pulseless electric activity (64%). Independent predictors of mortality were need for endotracheal intubation and older age, whereas ventricular fibrillation as initial heart rhythm was associated with survival. In conclusion, in this large registry with prehospital diagnosed STEMI, incidence of prehospital CPR was about 8%. Even with a very high rate of early reperfusion therapy, in-hospital mortality was high. Especially in elderly patients with asystole as initial heart rhythm and with need for endotracheal intubation, prognosis is poor despite aggressive reperfusion therapy. |
14,250 | LR-PED rule: low risk pulmonary embolism decision rule - a new decision score for low risk pulmonary embolism. | When accurately diagnosed, non-massive Pulmonary embolism (PE) has a low mortality rate. However, some patients initially considered to be low risk show progressive deterioration. This research aims at developing a preliminary score that allows detection of low risk patients potentially eligible for outpatient treatment.</AbstractText>Retrospective cohort study involving 142 asymptomatic/mildly symptomatic and hemodynamically stable patients with PE and no clinical/echocardiographic signs of right ventricular dysfunction. Collected data: risk factors, analytic/gasometric parameters, admission echocardiogram, thoracic CT angiography. Patients followed for 6months. Primary endpoint: 1-month all-cause mortality. Secondary endpoints: Intrahospital and 6-month all-cause mortality. A score designed for identification of very low risk patients eligible for outpatient treatment was developed and its prognostic accuracy compared to that of the Geneva and simplified PESI models.</AbstractText>A score for predicting 1-month mortality (Low Risk Pulmonary Embolism Decision [LR-PED] rule) was obtained using Binary Logistic Regression, including: age, atrial fibrillation at admission, previous heart failure, admission heart rate, creatinine, glycaemia, troponin I and C-reactive protein at admission. ROC curve analysis assessed its overall accuracy for predicting 1-month, intrahospital and 6-month mortality (AUC=0.756, 0.763 and 0.854, respectively). Compared to Geneva and simplified PESI, the LR-PED rule showed higher sensitivity and negative predictive value for the detection of the lowest risk patients. The net reclassification improvement index revealed significant successful upward risk reclassification by the LR-PED model of patients reaching primary or secondary outcomes.</AbstractText>LR-PED rule seems more attractive than Geneva or simplified PESI in its ability to identify patients at very low mortality risk who would be potentially eligible for outpatient treatment. Prospective validation of this score in larger cohorts is mandatory before its potential implementation.</AbstractText>Copyright © 2012 Elsevier Ltd. All rights reserved.</CopyrightInformation> |
14,251 | Anticoagulation therapy in patients with heart failure due to systolic dysfunction and sinus rhythm: analysis of REDINSCOR registry. | In patients with heart failure, left ventricular ejection fraction ≤35% and sinus rhythm without conditions such as atrial fibrillation, thrombus or history of thromboembolic events, the use of anticoagulation is controversial. Our objective was to evaluate the anticoagulation strategy in these patients, variables associated with its use, and its effects on various cardiovascular events.</AbstractText>Of the patients included in the REDINSCOR registry with left ventricular ejection fraction ≤35% and sinus rhythm without other anticoagulation indications (including patients with heart failure from 19 Spanish centres), we compared those who received this treatment with the remaining patients.</AbstractText>Between 2007 and 2010, 2263 patients were included, of whom 902 had left ventricular ejection fraction ≤35% and sinus rhythm. Of these, 237 (26%) were receiving anticoagulation therapy. Variables associated with this treatment were a lower left ventricular ejection fraction, ischemic etiology, advanced functional class, wider QRS, larger left atrial diameter, and hospitalization. After 21(11-32) months of median follow-up, there were no significant differences in total mortality (14% versus 12.5%) or stroke (0.8% versus 0.9%). A propensity score adjusted multivariate analysis showed a reduction in a combined end-point including cardiac death, heart transplantation, coronary revascularization, and cardiovascular hospitalization (hazard ratio: 0.74; 95% confidence interval, 0.56-0.97; P=.03) in patients receiving anticoagulation therapy. No information regarding bleeding was collected in the follow-up.</AbstractText>In a large and contemporary series of patients with heart failure, left ventricular ejection fraction ≤35% and sinus rhythm, 26% received anticoagulation therapy. This was not associated with lower mortality or stroke incidence, although there was a reduction in major cardiac events.</AbstractText>Copyright © 2011 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.</CopyrightInformation> |
14,252 | Nonlinearity between action potential alternans and restitution, which both predict ventricular arrhythmic properties in Scn5a+/- and wild-type murine hearts. | Electrocardiographic QT- and T-wave alternans, presaging ventricular arrhythmia, reflects compromised adaptation of action potential (AP) duration (APD) to altered heart rate, classically attributed to incomplete Na(v)1.5 channel recovery prior to subsequent stimulation. The restitution hypothesis suggests a function whose slope directly relates to APD alternans magnitude, predicting a critical instability condition, potentially generating arrhythmia. The present experiments directly test for such correlations among arrhythmia, APD alternans and restitution. Mice haploinsufficient in the Scn5a, cardiac Na(+) channel gene (Scn5a(+/-)), previously used to replicate Brugada syndrome, were used, owing to their established arrhythmic properties increased by flecainide and decreased by quinidine, particularly in right ventricular (RV) epicardium. Monophasic APs, obtained during pacing with progressively decrementing cycle lengths, were systematically compared at RV and left ventricular epicardial and endocardial recording sites in Langendorff-perfused Scn5a(+/-) and wild-type hearts before and following flecainide (10 μM) or quinidine (5 μM) application. The extent of alternans was assessed using a novel algorithm. Scn5a(+/-) hearts showed greater frequencies of arrhythmic endpoints with increased incidences of ventricular tachycardia, diminished by quinidine, and earlier onsets of ventricular fibrillation, particularly following flecainide challenge. These features correlated directly with increased refractory periods, specifically in the RV, and abnormal restitution and alternans properties in the RV epicardium. The latter variables were related by a unique, continuous higher-order function, rather than a linear relationship with an unstable threshold. These findings demonstrate a specific relationship between alternans and restitution, as well as confirming their capacity to predict arrhythmia, but implicate mechanisms additional to the voltage feedback suggested in the restitution hypothesis. |
14,253 | Paradoxical atrial undersensing by a dual chamber pacemaker during atrial fibrillation. | This report describes paradoxical atrial undersensing by a dual chamber pacemaker in a patient with paroxysmal atrial fibrillation. Atrial undersensing was present only when the device was programmed to a high sensitivity but sensing normalized when a lower sensitivity was programmed. This unusual response should be differentiated from the recently documented lock-in behavior of pacemakers delivering managed ventricular pacing. |
14,254 | Late diagnosis of congenital cardiovascular defect. | Coarctation of the aorta (CoA) is a common congenital anomaly that is usually treated in infancy or childhood. Adult patients with coarctation have a high incidence of associated cardiac disorders, including valve diseases, atrial fibrillation and ischemic heart disease. Most patients with uncorrected CoA die before reaching the age of 50 from complications such as myocardial infarction, intracranial hemorrhage, congestive heart failure (HF), infective endocarditis or aortic dissection. We report the case of a 65 year-old woman admitted to hospital with symptoms of heart failure NYHA class IV. She had been treated for several years for refractory arterial hypertension and concomitant stenocardia (II CCS). The symptoms of HF had been increasing over several months. Outpatient echocardiography examination revealed significant, increasing mitral and tricuspid valve regurgitation with progressive left ventricular dysfunction. The patient was referred for surgical repair of the mitral and tricuspid valves. In-hospital echocardiography and angiography revealed descending aorta discontinuity at the level of the aortic isthmus. This congenital disease revealed during hospitalization was determined to be the underlying cause of all the symptoms the patient presented. Due to the clinical status of the patient, she was discharged from surgical procedures and put on medication. |
14,255 | Left ventricular assist device implantation in a patient who had previously undergone apical myectomy for hypertrophic cardiomyopathy. | Apical hypertrophy is a rare variant of hypertropic cardiomyopathy. These patients may present with end-stage congestive heart failure subsequent to long standing diastolic dysfunction. We report the technique for left ventricular assist device insertion in a patient with previous apical myectomy for hypertrophic cardiomyopathy. |
14,256 | Why and how to support screening strategies to prevent sudden death in athletes. | Sudden death in athletes occurs because of the existence of hidden cardiovascular disorders which, during effort, may jeopardize the electrical stability of the heart, triggering ventricular tachycardia and/or fibrillation. Apart from rare conditions of ion channel diseases in the setting of a structurally normal heart, in which the disorder may be easily diagnosed on basal or stress test ECG, cardiac abnormalities at risk of causing sudden death may affect the aorta (Marfan syndrome), the coronary arteries (congenital coronary artery anomalies, premature coronary atherosclerosis), the myocardium (hypertrophic and arrhythmogenic cardiomyopathy), the valves (bicuspid aortic valve, mitral valve prolapse) and the conduction system (pre-excitation syndromes). These structural heart disorders may be detected by ECG and/or echo. The employment of these tools at pre-participation screening can help to identify concealed anomalies, which may play a major role in early diagnosis, risk stratification, and prevention of sudden death. |
14,257 | Tricuspid regurgitation after successful mitral valve surgery. | The tricuspid valve (TV) is inseparably connected with the mitral valve (MV) in terms of function. Any pathophysiological condition concerning the MV is potentially a threat for the normal function of the TV as well. One of the most challenging cases is functional tricuspid regurgitation (TR) after surgical MV correction. In the past, TR was considered to progressively revert with time after left-sided valve restoration. Nevertheless, more recent studies showed that TR could develop and evolve postoperatively over time, as well as being closely associated with a poorer prognosis in terms of morbidity and mortality. Pressure and volume overload are usually the underlying pathophysiological mechanisms; structural alterations, like tricuspid annulus dilatation, increased leaflet tethering and right ventricular remodelling are almost always present when regurgitation develops. The most important risk factors associated with a higher probability of late TR development involve the elderly, female gender, larger left atrial size, atrial fibrillation, right chamber dilatation, higher pulmonary artery systolic pressures, longer times from the onset of MV disease to surgery, history of rheumatic heart disease, ischaemic heart disease and prosthetic valve malfunction. The time of TR manifestation can be up to 10 years or more after an MV surgery. Echocardiography, including the novel 3D Echo techniques, is crucial in the early diagnosis and prognosis of future TV disease development. Appropriate surgical technique and timing still need to be clarified. |
14,258 | Unmasking of myopotential oversensing by an integrated bipolar defibrillator lead following AV node ablation. | A 73-year-old man with nonischemic cardiomyopathy underwent catheter ablation of ventricular tachycardia that had resulted in frequent shocks from his implanted cardiac resynchronization therapy defibrillator (CRT-D). Coexisting atrial fibrillation required AV node ablation which rendered the patient pacemaker dependent. During follow-up, recurrent episodes of dizziness occurred caused by inhibition of pacing due to oversensing of pectoral muscle myopotentials. Surgical revision was performed and the intraoperative examination revealed an intact integrated bipolar defibrillator lead with appropriate connections to the CRT-D header. The placement of an additional pace/sense lead completely resolved the patient's symptoms and no further myopotential oversensing was recorded. |
14,259 | Genetic suppression of Gαs protein provides rate control in atrial fibrillation. | Gene therapy-based modulation of atrioventricular (AV) conduction by overexpression of a constitutively active inhibitory Gα(i) protein effectively reduced heart rates in atrial fibrillation (AF). However, catecholamine stimulation caused an excessive increase in ventricular rate. We hypothesized that modest genetic suppression of a stimulatory G protein in the AV node would allow persistent rate control in acute AF and would prevent undesired heart rate acceleration during β-adrenergic activation. Atrial fibrillation was induced in 12 pigs by atrial burst pacing via an implanted cardiac pacemaker. Study animals were then assigned to receive either Ad-siRNA-Gα(s) gene therapy to inactivate Gα(s) protein or Ad-β-gal as control. Gα(s) protein inactivation resulted in a 20 % heart rate reduction (P < 0.01). AH and HV intervals were prolonged by 37 ms (P < 0.001) and 28 ms (P < 0.001), respectively, demonstrating atrioventricular conduction delay. Impairment of left ventricular ejection fraction (LVEF) during AF was attenuated by Gα(s) suppression (LVEF 49 %) compared with controls (LVEF 34 %; P = 0.03). Isoproterenol application accelerated ventricular heart rate from 233 to 281 bpm (P < 0.001) in control animals but did not significantly affect pigs treated with Ad-siRNA-Gα(s) (192 vs. 216 bpm; P = 0.19). In conclusion, genetic inhibition of Gα(s) protein in the AV node reduced heart rate and prevented AF-associated reduction of cardiac function in a porcine model. Rate control by gene therapy may provide an alternative to current pharmacological treatment of AF. |
14,260 | Novel mutations in the KCND3-encoded Kv4.3 K+ channel associated with autopsy-negative sudden unexplained death. | Heritable arrhythmia syndromes, including Brugada syndrome (BrS) and idiopathic ventricular fibrillation (IVF), may serve as the pathogenic basis for autopsy-negative sudden unexplained death (SUD) and sudden infant death syndrome (SIDS). Emerging evidence has linked perturbations in the transient outward current (I(to) ) conducted by the KCND3-encoded Kv4.3 pore-forming α-subunit to BrS or IVF. However, the contribution of KCND3 mutations to autopsy-negative SUD/SIDS is unknown. To investigate the potential association between KCND3 and SUD/SIDS, mutational analysis of KCND3 was conducted in 123 SUDS and 292 SIDS victims using polymerase chain reaction, denaturing high-performance liquid chromatography, and direct sequencing. Overall, one SIDS case (<1.0%) and two SUDS cases (1.6%) harbored potentially pathogenic mutations in KCND3. The novel p.Val392Ile, p.Ser530Pro, and p.Gly600Arg mutations involved highly conserved residues and were absent in 1,560 reference alleles. Although the SIDS-associated p.Ser530Pro mutation demonstrated a wild-type (WT) electrophysiological phenotype when heterologously expressed, the SUDS-associated p.Val392Ile and p.Gly600Arg mutations significantly increased peak current density at +40 mV in comparison with WT by 100.4% (P < 0.05) and 50.4% (P < 0.05), respectively. p.Val392Ile also slowed recovery from inactivation 3.6-fold, indicating a mixed electrophysiological phenotype. This is the first report indicating that KCND3 may serve as a rare genetic substrate in the pathogenesis of SUDS but not SIDS cases. |
14,261 | [Commentary on the 2010 ESC guidelines on device therapy in heart failure ]. | As part of the 2010 focused update of ESC guidelines on device therapy in heart failure, the guidelines on pacemakers in the treatment of heart failure were renewed. A new feature is that cardiac resynchronization therapy (CRT) is indicated for New York Heart Association (NYHA) class III and IV irrespective of the presence of left ventricular dilatation and specified for NYHA class IV (patient ambulatory, stable, life expectancy >6 months). Furthermore, NYHA class II (but not class I) has been added when there is left bundle branch block and QRS duration ≥150 ms. CRT is also indicated for patients in NYHA class III-IV with permanent atrial fibrillation and heart failure [left ventricular ejection fraction (LVEF) ≤ 35%] when QRS is ≥ 130 ms and ventricular rate has slowed either spontaneously or by AV node ablation. In patients with heart failure (NYHA class II-IV, LVEF ≤ 35%) who need a pacemaker for AV block, CRT is generally indicated to avoid progression of heart failure caused by right ventricular stimulation, also in cases of intrinsic QRS <120 ms. For patients with terminal heart failure who are not eligible for heart transplantation, treatment with a left ventricular assist device can be performed as destination therapy. The new guidelines expand the indication for device therapy in heart failure based on the newest study findings, particularly for patients in NYHA class II, and specify the old guidelines. There are still uncertainties that must be investigated in randomized trials regarding patients with permanent atrial fibrillation, the indication for CRT in heart block, and the question of CRT with pacemaker or defibrillator. |
14,262 | Long-term outcomes of mechanical valve replacement in patients with atrial fibrillation: impact of the maze procedure. | The long-term benefits of the maze procedure in patients with chronic atrial fibrillation undergoing mechanical valve replacement who already require lifelong anticoagulation remain unclear.</AbstractText>We evaluated adverse outcomes (death; thromboembolic events; composite of death, heart failure, or valve-related complications) in 569 patients with atrial fibrillation-associated valvular heart disease who underwent mechanical valve replacement with (n=317) or without (n=252) a concomitant maze procedure between 1999 and 2010. After adjustment for differences in baseline risk profiles, patients who had undergone the maze procedure were at similar risks of death (hazard ratio, 1.15; 95% confidence interval, 0.65-2.03; P=0.63) and the composite outcomes (hazard ratio, 0.82; 95% confidence interval, 0.50-1.34; P=0.42) but a significantly lower risk of thromboembolic events (hazard ratio, 0.29; 95% confidence interval, 0.12-0.73; P=0.008) compared with those who underwent valve replacement alone at a median follow-up of 63.6 months (range, 0.2-149.9 months). The effect of superior event-free survival by the concomitant maze procedure was notable in a low-risk EuroSCORE (0-3) subgroup (P=0.049), but it was insignificant in a high-risk EuroSCORE (≥4) subgroup (P=0.65). Furthermore, the combination of the maze procedure resulted in superior left ventricular (P<0.001) and tricuspid valvular functions (P<0.001) compared with valve replacement alone on echocardiographic assessments performed at a median of 52.7 months (range, 6.0-146.8 months) after surgery.</AbstractText>Compared with valve replacement alone, the addition of the maze procedure was associated with a reduction in thromboembolic complications and improvements in hemodynamic performance in patients undergoing mechanical valve replacement, particularly in those with low risk of surgery.</AbstractText> |
14,263 | The ratio of observed to predicted left ventricular mass is independently associated with increased cardiovascular events in patients with chronic kidney disease. | A condition involving the growth of the myocardium that exceeds hemodynamic needs has been reported and called as inappropriate left ventricular mass (LVM). The appropriateness of LVM can be estimated by the ratio of observed LVM to predicted LVM. The excessive growth of LVM is frequently noted in patients with chronic kidney disease (CKD). This study is designed to assess whether the ratio of observed to predicted LVM is a useful prognostic indicator of cardiovascular events in patients with moderate to advanced CKD. We consecutively enrolled 485 patients with CKD stages 3-5 from our Outpatient Department of Internal Medicine. Inappropriate LVM was defined as observed LVM more than 28% greater than the predicted value. The relative risk of cardiovascular events was analyzed by Cox-regression methods. There was a significant trend for a stepwise increase in the observed/predicted LVM ratio (P<0.001) and the prevalence of inappropriate LVM (P=0.003) corresponding to advances in CKD stages. In the multivariate analysis, old age, a history of coronary artery disease, congestive heart failure, atrial fibrillation, wide pulse pressure, decreased serum albumin and hemoglobin levels, left atrial diameter >4.7 cm and increased observed/predicted LVM were independently associated with increased cardiovascular events. Our findings show that increased observed/predicted LVM is independently associated with adverse cardiovascular outcomes in patients with CKD stages 3-5. |
14,264 | [The influence of heartbeat acceptance window settings on left ventricular function and perfusion parameters]. | To evaluate the influence of heartbeat acceptance window settings on left ventricular function and perfusion parameters of the arrhythmia patients during gated myocardial perfusion imaging.</AbstractText>Twenty eight fibrillation patients were consecutively recruited to undergo myocardial perfusion SPECT. The Concurrent Imaging software was used to create 3 separate SPECT studies with heartbeat acceptance window of 20%, 60% and 100% respectively. The software created the 3 studies separately rather than a rearrangement of an original list-mode acquisition. After reconstruction by Astonish, end-diastole volume (EDV) and end-systolic volume (ESV), left ventricular ejection fraction (LVEF), sum stress score (SSS), and sum rest score (SRS) were calculated with Quantitative Gated SPECT (QGS). Analyses of variance were performed using SPSS to compare the differences in EDV, ESV, EF, SSS, and SRS among the three studies.</AbstractText>85.7% of the 28 patients had abnormal perfusing. No statistical differences were found in EDV, ESV, EF, SSS, and SRS among the 3 studies. But the collection time was 40.5 min, 25.6 min and 15.0 min for heartbeat acceptance window of 20%, 60% and 100% respectively.</AbstractText>Heartbeat acceptance window setting does not have a significant effect on EDV, ESV, EF, SSS, and SRS values. The wider the window is set, the shorter the collection time is.</AbstractText> |
14,265 | Atrial flutter in normal heart could be first manifestation of Brugada syndrome. | Brugada syndrome is one of the important causes of sudden cardiac death in young adults. The condition is associated with typical ECG changes in anteroseptal leads V1 and V2 that can be unmasked by various medications, electrolyte disturbances, and even by fever in susceptible individuals. We here report the case of a 22-year-old female admitted to the emergency room with a typical atrial flutter who developed Brugada-like ECG changes after conversion to sinus rhythm following flecainide infusion with subsequent degeneration in ventricular fibrillation. The patient converted to sinus rhythm after external DC shock intervention. At hospital admission she reported no family history of sudden cardiac death, nor syncope or paroxysmal palpitations. The cardiac echocardiographical exam revealed no structural abnormalities and a normal ejection fraction. This case highlights once more the importance of recognising supraventricular arrhythmias or other rhythm disturbances in young healthy patients as the revealing sign of other underlying pathologies. |
14,266 | Dialysis-dependent changes in ventricular repolarization. | Epidemiological data suggest increased risk of sudden death during and immediately after hemodialysis. Microvolt T-wave alternans (mTWA) is an electrocardiogram (ECG) measure of abnormal ventricular repolarization, which can be used in sudden death risk stratification. The aim of this study was to determine whether mTWA measurements during dialysis indicate abnormal repolarization as a potential trigger to dialysis associated arrhythmias.</AbstractText>Forty-eight-hour, 12-lead Holter ECG recordings were taken on a cohort of maintenance hemodialysis patients. Modified moving average mTWA was examined for 48 hours from the start of dialysis. Predialysis biochemistry was taken and echocardiography was performed on a nondialysis day.</AbstractText>Nineteen patients were analyzed (age 61 ± 14 years, time on dialysis 2.7 ± 2 years). mTWA increased during dialysis (P < 0.01) but returned to baseline 2 hours postdialysis (first hour mTWA = 10.1 ± 4.5μV, final hour mTWA = 12.2 ± 3.7μV, postdialysis mTWA = 10.3 ± 2.7μV, P = 0.015). The change in mTWA did not correlate with serum biochemistry or echocardiographic measurements of left ventricular mass and function. Peak mTWA and frequency of spikes in mTWA ≥ 65μV were not more common during dialysis compared to other times. Patients who showed greater frequency of spikes ≥65μV or increase in hourly mean mTWA during dialysis did not have a worse cardiovascular outcome over a mean follow-up of 2.6 years.</AbstractText>Though there were subtle changes in mTWA during dialysis, there was no association with mTWA abnormalities previously shown to be associated with worse outcome. The presence of abnormal mTWA did not correlate with outcome.</AbstractText>©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.</CopyrightInformation> |
14,267 | A randomized study of defibrillator lead implantations in the right ventricular mid-septum versus the apex: the SEPTAL study. | The study was designed to evaluate the feasibility and performance of right ventricular (RV) mid-septal versus apical implantable defibrillator (ICD) lead placement.</AbstractText>SEPTAL is a randomized, noninferiority trial, which randomly assigned patients to implantation of ICD leads in the RV mid-septum versus apex, with a primary objective of comparing the implant success rate of implant at each site, based on strict electrical predefined criteria. We also compared the (1) pacing lead characteristics, (2) rates of appropriate and inappropriate ICD therapies, and (3) all-cause mortality between the 2 sites at 1 year. The trial enrolled 215 patients (mean age = 59.7 ± 12.4 years, mean LVEF = 34.0 ± 14.2%, 84.2% men), of whom 148 (68.8%) presented with ischemic heart disease. The ICD indication was primary prevention in 117 patients (54.4%). The lead was successfully implanted in 96/107 patients (89.7%) assigned to the RV mid-septum, and in 99/108 (91.7%) assigned to the apex (ns). The 1-year rate of lead-related adverse events was similar in both groups. A total of 8 first inappropriate ICD therapies (7.9%) were delivered in the RV mid-septal group, versus 8 (7.8%) in the apical group (ns), while first appropriate therapies were delivered to 22 (21.4%) and 24 patients (23.8%), respectively (ns). All-cause mortality was 7.9% in the RV mid-septal versus 2.9% in the RV apical group (ns).</AbstractText>This study confirmed the technical feasibility and noninferior performance of ICD leads implanted in the RV mid-septum versus the apex.</AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
14,268 | Adverse effects of long-term right ventricular apical pacing and identification of patients at risk of atrial fibrillation and heart failure. | In patients needing a pacemaker (PM) for bradycardia indications, the amount of right ventricular (RV) apical pacing has been correlated with atrial fibrillation (AFib) and heart failure (HF) in both DDD and VVI mode. RV pacing was linked with left ventricular (LV) dyssynchrony in almost 50% of patients with PM implantation and atrioventricular (AV) node ablation for AFib. In patients with normal systolic function needing a PM, apical RV pacing resulted in LV ejection fraction (LVEF) reduction. These negative effects were prevented by cardiac resynchronization therapy (CRT). Algorithms favoring physiological AV conduction are possible useful tools able to maintain both atrial and ventricular support and limit RV pacing. However, when chronic RV pacing cannot be avoided, it appears necessary to reconsider the cut-off value of basic LVEF for CRT. In HF patients, RV pacing can induce greater LV dyssynchrony, enhanced by underlying conduction diseases. In this context, a more deleterious effect of RV pacing in implantable cardioverter-defibrillator (ICD) patients with low LVEF can be expected. In some major ICD trials, DDD mode was correlated with increased mortality/HF. This negative impact was attributed to unnecessary RV pacing >40-50%, virtually absent in VVI-40 mode. However, some data suggest that avoiding RV pacing may also not be the best option for patients requiring an ICD. In patients with impaired LV function, AV synchrony should therefore be ensured. The best pacing mode in ICD patients with HF should be defined on an individual basis. |
14,269 | Left ventricular diastolic dysfunction in patients with metabolic syndrome. | Metabolic syndrome (MetS), which is a cluster of medical disorders, is common and it is associated with increased cardiovascular morbidity and mortality. The aim of this study was to evaluate the relationship between characteristics of metabolic syndrome and the grade of diastolic dysfunction. The study included 72 patients (29 male and 43 female), who had central obesity and at least two of the other four characteristics of metabolic syndrome according to IDF (International Diabetes Federation) criteria. The exclusion criteria were age above 65, impaired systolic function (left ventricular ejection fraction < 55%) atrial fibrillation, valvular and pericardial heart disease. Diastolic function was determined according to the criteria of the American Society of Echocardiography. There was a positive correlation between the number of characteristics of metabolic syndrome and the diastolic dysfunction grade (p < 0.0001). The positive correlation was found between the grade of diastolic dysfunction and the waist circumference (p < 0.0001), arterial hypertension (p < 0.001). pared glucose tolerance/diabetes (P = 0.0063), and hypertriglyceridemia (p = 0.0262). A low level of high-density lipoprotein did not show a statistically significant correlation. The presence of metabolic syndrome is associated with the presence of diastolic dysfunction. The grade of diastolic dysfunction is dependent on the number of coexisting characteristics of metabolic syndrome. Arterial hypertension, central obesity, hyperglycemia and hypertriglyceridemia showed a significant correlation with the degree of diastolic dysfunction. |
14,270 | Acupuncture for paroxysmal and persistent atrial fibrillation: An effective non-pharmacological tool? | In Traditional Chinese Medicine, stimulation of the Neiguan spot has been utilized to treat palpitations and symptoms related to different cardiovascular diseases. We evaluated whether acupuncture might exert an antiarrhythmic effect on patients with paroxysmal or persistent atrial fibrillation (AF). Two sets of data are reviewed. The first included patients with persistent AF who underwent electrical cardioversion to restore sinus rhythm. The second included patients with symptomatic paroxysmal AF. All subjects had normal ventricular function. Acupuncture treatment consisted of 10 acupuncture sessions on a once a week basis with puncturing of the Neiguan, Shenmen and Xinshu spots. In patients with persistent AF, the recurrence rate after acupuncture treatment was similar to that observed in patients on amiodarone, but significantly smaller than that measured after sham acupuncture treatment or in the absence of any antiarrhythmic drugs. In a small group of patients with paroxysmal AF, acupuncture resulted in a significant reduction in the number and duration of symptomatic AF episodes. In conclusion, we observed that acupuncture of the Neiguan spot was associated with an antiarrhythmic effect, which was evident in patients with both persistent and paroxysmal AF. These preliminary data, observed in 2 small groups of AF patients, need to be validated in a larger population but strongly suggest that acupuncture may be an effective non-invasive and safe antiarrhythmic tool in the management of these patients. |
14,271 | Antithrombotic therapy for stroke prevention in patients with heart failure. | Congestive heart failure (CHF) is associated with an increased risk of stroke mainly due stasis leading to increased risk of thrombus formation in the left ventricle and subsequent cerebral embolism. CHF patients are also at increased risk of atrial fibrillation (AF) that also leads to cerebral embolism. Aggressive medical management to prevent cardiac decompensation and maintain sinus rhythm is indicated in CHF patients. All patients with CHF and AF should be anticoagulated with warfarin or one of the newer oral anticoagulants. There is no clear indication for anticoagulation in CHF patients due to ischemic cardiomyopathy who are in sinus rhythm. Based on data from the WARCEF study (see below), those patients with CHF due to non-ischemic etiologies who are in sinus rhythm and have a left ventricular ejection fraction (LVEF) less than 30 % to 35 % may benefit from warfarin for the reduction of ischemic stroke risk, but warfarin does not increase survival. Whether warfarin is particularly beneficial for CHF patients who have a prior history of stroke or transient ischemic attack (TIA) is unknown. If, however, there is high enough suspicion that the stroke was of cardioembolic origin in patients with low LVEF, then anticoagulation would possibly be a reasonable option for prevention of recurrent stroke or TIA. Warfarin is indicated for stroke prophylaxis among those CHF patients who have an implanted mechanical device. The role of newer anticoagulants in patients with CHF who do not have AF is unknown at this time. Theoretically, there should be no reason against using these agents in place of warfarin in selected patients, particularly those with highly variable International Normalized Ratios (INR) in the context of warfarin therapy, but the newer anticoagulants have not yet been studied among CHF patients without concomitant AF. |
14,272 | Prognostic value of QRS fragmentation in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia. | QRS fragmentation, including epsilon potentials, terminal activation delay and prolonged S wave upstroke, has been recently described as a diagnostic criterion of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). Whether QRS fragmentation is a marker of recurrent ventricular tachycardia, primary ventricular fibrillation, implantable cardioverter defibrillator (ICD) discharge and sudden cardiac death in these patients is unknown.</AbstractText>Three hundred and thirty-five patients (167 men, mean age 46.3 ± 14.6 years) with ARVC/D according to International Society and Federation of Cardiology/European Society of Cardiology (ISFC/ESC) criteria were analyzed retrospectively. Patients with complete and incomplete right bundle branch block were excluded from the analysis. At 6.3 ± 3.1 years mean follow-up, seven patients (0.02%) had died suddenly, 39 patients (0.13%) experienced recurrent ventricular tachycardia, 32 patients (0.1%) presented with primary ventricular fibrillation and 30 patients (0.1%) had recurrent ICD discharges. QRS fragmentation was significantly associated with arrhythmic events (P < 0.0000001 for the endpoint of sudden cardiac death, P < 0.01 for recurrent ventricular tachycardia, P < 0.0001 for primary ventricular fibrillation and P < 0.001 for recurrent ICD discharges, respectively).</AbstractText>QRS fragmentation predicts arrhythmic events in patients with ARVC/D. Further, properly designed prospective studies are warranted to confirm these findings.</AbstractText> |
14,273 | Thiazolidinedione drugs promote onset, alter characteristics, and increase mortality of ischemic ventricular fibrillation in pigs. | Despite favorable metabolic and vascular effects, thiazolidinedione (TZD) drugs have not convincingly reduced cardiovascular mortality in clinical trials, raising the possibility of countervailing, off-target effects. We previously showed that TZDs block cardiac ATP-sensitive potassium (K(ATP)) channels in pigs. In this study, we investigated whether TZDs affect onset, spectral characteristics, and mortality of ischemic ventricular fibrillation (VF) and whether such effects are recapitulated by a non-selective K(ATP) blocker (glyburide) or a mitochondrial K(ATP) blocker (5-hydroxydecanoate).</AbstractText>A total of 121 anesthetized pigs were pre-treated with TZD (pioglitazone or rosiglitazone, 1 mg/kg IV, resulting in clinically relevant plasma concentrations), glyburide (1 mg/kg IV), 5-hydroxydecanoate (5 mg/kg IV) or inert vehicle. Ischemia was produced by occlusion of the left anterior descending coronary artery. In a subset of pigs treated with rosiglitazone or vehicle, ischemic preconditioning was performed.</AbstractText>VF developed in all but 6 pigs. In non-preconditioned pigs, onset of VF occurred sooner with pioglitazone (11±3 min, p<0.05) or rosiglitazone (14±3 min, p=0.06) than with vehicle (20±2 min). Defibrillation of VF was successful in 44% of pigs treated with vehicle, compared with 0% with pioglitazone (p=0.057) and 33% with rosiglitazone (NS). After ischemic preconditioning, defibrillation was successful in 62% of pigs treated with vehicle, compared with 26% treated with rosiglitazone (p=0.03). TZDs attenuated slowing of conduction due to ischemia and shifted ECG power spectra during VF toward higher frequencies. All effects of TZDs were recapitulated by glyburide, but not by 5-hydroxydecanoate, supporting an interaction of TZDs with the sarcolemmal K(ATP) channel.</AbstractText>In a porcine model, TZDs promote onset and increase mortality of ischemic VF, associated with alterations of conduction and VF spectral characteristics. Similar effects in a clinical setting might adversely impact cardiovascular mortality.</AbstractText> |
14,274 | Early repolarization and short QT interval in healthy subjects. | An early repolarization (ER) pattern is common in ECGs from patients with ventricular fibrillation (VF). These patients with ER have shorter QT intervals. Morphological variants of the ER pattern also have been associated with idiopathic VF, but their prevalence in healthy subjects is unclear.</AbstractText>The purpose of this study was to study the prevalence of ER and its morphological variants, and its association with the QTc interval in healthy subjects.</AbstractText>Digital ECGs from 1886 healthy subjects from Phase I clinical trials were analyzed by a central ECG laboratory.</AbstractText>ER, defined as J-point elevation ≥0.1 mV in ≥2 contiguous leads, was present in 514 subjects (27.3%), of whom 505 (98.2%) were males. The prevalence of ER declined progressively with increasing age. ER pattern was seen in lateral leads (I, aVL, V(4)-V(6)) in 26.1%, in inferior (II, III, aVF) or inferolateral leads in 8%, and was global in 1.9%. The terminal portion of the QRS complex was notched in 43.1% and slurred in 56.9%. Notching was common in inferior/lateral leads, and slurring was common in anterior leads. A non-ascending ST segment was seen in 71% of ECGs with a notched pattern but in only 12.3% of ECGs with a slurred pattern. The ER group had slower heart rates (9.3 ± 13.3 bpm [mean difference ± SD], P <.001) and shorter QTc intervals (QTcB = 20.2 ± 25.6 ms, QTcF = 11.0 ± 21.9 ms; P <.001). Four subjects in each group had a short QT interval (QTcF <350 ms).</AbstractText>ER and all of its variants are common in healthy young males with slower heart rates and slightly shorter QTc intervals. A short QT interval (QTcF <350 ms) is rare.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,275 | Effects of ventricular pacing protocol on electrical restitution assessments in guinea-pig heart. | The steep slope of the rate adaptation of ventricular action potential duration (APD) is thought to indicate profibrillatory tendency. In cardiac patients, APD restitution is commonly assessed by extrasystolic (S(1)-S(2)) stimulations rather than dynamic pacing, because the latter may provoke myocardial ischaemia. In this study, ventricular APD and effective refractory period (ERP) were measured in perfused guinea-pig hearts to determine whether S(1)-S(2) stimulations and dynamic pacing may have similar value in APD restitution assessments aimed to predict arrhythmic risk. The maximal restitution slope was greater upon S(1)-S(2) stimulation than dynamic pacing at the epicardium (S(1)-S(2), 1.2 ± 0.08; dynamic, 0.72 ± 0.06; P = 0.0004) and endocardium (S(1)-S(2), 1.45 ± 0.08; dynamic, 0.95 ± 0.06; P = 0.0003). This difference was partly accounted for by an effect of the previous pacing history, as evidenced by flattening of APD restitution upon reductions in the regular beating interval prior to S(2) application. Furthermore, shorter ERP than APD relationships enabled ventricular capture at shorter diastolic intervals during S(1)-S(2) stimulation than dynamic pacing at the epicardium (S(1)-S(2), -1 ± 3 ms; dynamic, 35 ± 3 ms; P < 0.0001) and endocardium (S(1)-S(2), -1 ± 7 ms; dynamic, 38 ± 3 ms; P < 0.0001), thereby contributing to greater maximal restitution slope values. Flecainide, a Na(+) channel blocker, increased the ERP-to-APD ratio and eliminated early premature beats (diastolic interval of ∼0 ms), thereby flattening the S(1)-S(2) restitution curve, but had no effect on dynamic restitution. In hypokalaemia-induced arrhythmogenicity, a reduction in ventricular fibrillation threshold was paralleled by increased steepness of dynamic APD restitution, while no change in the maximal restitution slope was revealed by S(1)-S(2) stimulations. In summary, changes in electrical restitution obtained from extrasystolic stimulations may dissociate from those revealed by dynamic pacing. These findings therefore challenge the value of electrical restitution assessments based on extrasystolic stimulation alone, as commonly performed in the clinical setting. |
14,276 | A novel, minimally invasive, segmental myocardial infarction with a clear healed infarct borderzone in rabbits. | Ventricular arrhythmias in the setting of a healed myocardial infarction have been studied to a much lesser degree than acute and subacute infarction, due to the pericardial scarring, which results from the traditional open-chest techniques used for myocardial infarction (MI) induction. We sought to develop a segmental MI with low perioperative mortality in the rabbit that allows optimal visualization and therefore improved study of the infarction borderzone. Rabbits underwent MI using endovascular coil occlusion of the first obtuse marginal artery. Three weeks postprocedure, we evaluated our model by echocardiography and electrophysiology studies, optical mapping of isolated hearts, and histological studies. Seventeen rabbits underwent the protocol (12 MI and 5 sham) with a 92% survival to completion of the study (11 MI and 5 sham). MI rabbits demonstrated wall motion abnormalities on echocardiography while shams did not. At electrophysiological study, two MI rabbits had inducible ventricular tachycardia and one had inducible ventricular fibrillation. Isolated hearts demonstrated no pericardial scarring with a smooth, easily identifiable infarct borderzone. Optical mapping of the borderzone region showed successful mapping of peri-infarct reentry formation, with ventricular fibrillation inducible in 11 of 11 MI hearts and 1 of 5 sham hearts. We demonstrate successful high resolution mapping in the borderzone, showing delayed conduction in this region corresponding to late deflections in the QRS on ECG. We report the successful development of a minimally invasive MI via targeted coil delivery to the obtuse marginal artery with an exceptionally high rate of procedural survival and an arrhythmogenic phenotype. This model mimics human post-MI on echocardiography, gross pathology, histology, and electrophysiology. |
14,277 | Long-term results of mitral repair for functional mitral regurgitation in idiopathic dilated cardiomyopathy. | While the results of mitral repair in ischaemic mitral regurgitation have been repeatedly reported, less data are available about the outcome of surgical repair of functional mitral regurgitation (FMR) in idiopathic dilated cardiomyopathy (iDCM) which represents the topic of this study.</AbstractText>Fifty-four iDCM patients (mean age 63 ± 10.5 years) underwent mitral valve repair for severe FMR. Coronary angiography confirmed the absence of coronary disease in all patients. Most of the patients (77.7%) were in New York Heart Association (NYHA) class III-IV. Pre-operative ejection fraction (EF) was 30.4 ± 8.5%, left ventricle end-diastolic diameter (LVEDD) 67.5 ± 7.8 mm, left ventricle end-systolic diameter (LVESD) diameter 53.9 ± 8.3 mm. Concomitant procedures were atrial fibrillation (AF) ablation (19 patients) and tricuspid repair (17 patients). Follow-up was 100% complete (mean 4.2 ± 2.5 years, median 4.2 years, range 3.3 months-11.1 years).</AbstractText>In-hospital mortality was 5.6%. Actuarial survival at 6.5 years was 69 ± 8.8%. Patients submitted to successful AF ablation and/or cardiac resynchronization therapy (CRT) had a significantly better survival (91 ± 7.9 vs 67 ± 9.5%, P = 0.01). Freedom from MR≥3+/4+ was 89.1 ± 5.7% at 6.5 years. Follow-up echocardiography showed a reduction in LVEDD (P < 0.0001) and LVESD (P = 0.0003). Mean EF increased to 38.7 ± 12.4% (P < 0.0001). Multivariate analysis identified successful ablation of AF and/or CRT (P = 0.01) and higher preoperative EF (0.03) as predictors of overall survival. Successful ablation of AF and/or CRT (P = 0.02) and lower preoperative systolic pulmonary artery pressure (0.04) were identified as independent predictors of reverse LV remodelling at follow-up. At last follow-up, 86.2% of the patients were in NYHA II or less.</AbstractText>Mitral repair for FMR in well-selected iDCM patients is associated with low hospital mortality and significant clinical benefit at late follow-up. Concomitant successful AF ablation and/or CRT provide a major symptomatic and prognostic advantage and should be associated to mitral surgery whenever indicated.</AbstractText> |
14,278 | Clinical context and mechanism of functional tricuspid regurgitation in patients with and without pulmonary hypertension. | Functional tricuspid regurgitation (FTR) with structurally normal valve is of poorly defined mechanisms. Prevalence and clinical context of idiopathic FTR (Id-FTR) (without overt TR cause) are unknown.</AbstractText>To investigate prevalence, clinical context, and mechanisms specific to FTR types, Id-FTR versus pulmonary hypertension-related (PHTN-FTR, systolic pulmonary pressure ≥50 mm Hg), we analyzed 1161 patients with prospectively quantified TR. Id-FTR (prevalence 12%) was associated with aging and atrial fibrillation. For mechanistic purposes, we measured valvular and right ventricular (RV) remodeling in 141 Id-FTR matched to 140 PHTN-FTR and to 99 controls with trivial TR for age, sex, atrial fibrillation, and ejection fraction. PHTN-FTR and Id-FTR were also matched for TR effective-regurgitant-orifice (ERO). Id-FTR valvular alterations (versus controls) were largest annular area (3.53±0.6 versus 2.74±0.4 cm(2), P<0.0001) and lowest valvular/annular coverage ratio (1.06±0.1 versus 1.45±0.2, P<0.0001) but normal valve tenting height. PHTN-FTR had mild annular enlargement but excessive valve tenting height (0.8±0.3 versus 0.35±0.1 cm, P<0.0001). Valvular changes were linked to specific RV changes, largest basal dilatation, and normal length (RV conical deformation) in Id-FTR versus longest RV with elliptical/spherical deformation in PHTN-FTR. With increasing FTR severity (ERO ≥40 mm(2)), changes specific to each FTR type were accentuated, and RV function (index of myocardial performance) was consistently reduced.</AbstractText>Id-FTR is frequent, linked to aging and atrial fibrillation, can be severe, and is of unique mechanism. In Id-FTR, excess annular and RV-basal enlargement exhausts valvular/annular coverage reserve, and RV conical deformation does not cause notable valvular tenting. Conversely, PHTN-FTR is determined by valvular tethering with tenting linked to RV elongation and elliptical/spherical deformation. These specific FTR-mechanisms may be important in considering surgical correction in FTR.</AbstractText> |
14,279 | Sevoflurane postconditioning attenuates reperfusion-induced ventricular arrhythmias in isolated rat hearts exposed to ischemia/reperfusion injury. | Sevoflurane postconditioning has been proven to protect the hearts against ischemia/reperfusion injury, manifested mainly by improved cardiac function, reduced myocardial specific biomarker release, and decreased infarct size. This study is to observe the effects of sevoflurane postconditioning on reperfusion-induced ventricular arrhythmias and reactive oxygen species generation in Langendorff perfused rat hearts. Compared with the unprotected hearts subjected to 25 min of global ischemia followed by 30 min of reperfusion, exposure of 3% sevoflurane during the first 15 min of reperfusion significantly improved cardiac function, reduced cardiac troponin I release, decreased infarct size and attenuated reperfusion-induced ventricular arrhythmia. Further analysis on arrhythmia during the 30 min of reperfusion showed that, sevoflurane postconditioning decreased both the duration and incidence of ventricular tachycardia and ventricular fibrillation. In the meantime, intracellular malondialdehyde and reactive oxygen species levels were also reduced. These above results demonstrate that sevoflurane postconditioning protects the hearts against ischemia/reperfusion injury and attenuates reperfusion-induced arrhythmia, which may be associated with the regulation of lipid peroxidation and reactive oxygen species generation. |
14,280 | Perivertebral B-cell lymphoma in a Queensland koala (Phascolarctos cinereus adustus) with paralytic symptoms in the hind limbs. | A male Queensland koala (Phascolarctos cinereus adustus) at Kanazawa Zoological Gardens (Kanagawa, Japan) exhibited paralytic symptoms in the hind limbs. Computed tomography and magnetic resonance imaging revealed a mass on the left ventral side of the 11th to 13th thoracic vertebrae, and the presence of myelitis or edema in the spinal cord. The koala was under anesthesia during the examination and suddenly developed ventricular fibrillation and died. Necropsy revealed a firm flat ovoid hemorrhagic mass on the vertebrae. Following a microscopic examination including immunohistochemistry, the perivertebral mass was diagnosed as B cell lymphoma. Therefore, neoplastic cell infiltration into the spinal cord may cause paralytic symptoms in the hind limbs. |
14,281 | Female sex is not associated with improved rates of ROSC or short term survival following prolonged porcine ventricular fibrillation. | There may be a survival benefit in female patients experiencing cardiac arrest, which could affect the interpretation of in vivo animal studies. We hypothesized that sex predicts return of spontaneous circulation (ROSC) and short-term survival (SURV) in porcine studies of prolonged ventricular fibrillation (VF).</AbstractText>Retrospective analysis of eight comparable experiments performed in our lab using mixed-breed domestic swine of either sex. All experiments included prolonged untreated VF, CPR, defibrillation, and drugs. We defined ROSC as systolic blood pressure ≥80 mm Hg for ≥1 min. Short-term survival was defined 20 or 60 min, depending on protocol. Categorical variables were compared with chi-square test and Fisher's exact test. Continuous variables were compared with two-sample t-test and one-way ANOVA. Multiple logistic regression determined predictors of ROSC and SURV, utilizing cluster analysis by experimental protocol. Candidate variables were sex, weight, anesthesia duration, VF duration, and CPR ratio.</AbstractText>Of 263 swine analyzed (53.2% male), 58.6% of males and 68.3% of females had ROSC (p=0.10), whereas 50.0% of males and 61.0% of females experienced SURV (p=0.07).</AbstractText>Of 263 swine analyzed (53.2% male), 58.6% of males and 68.3% of females had ROSC (p=0.10), whereas 50.0% of males and 61.0% of females experienced SURV (p=0.07). Neither sex nor any identified candidate variable predicted ROSC or SURV. Both models had acceptable fit with Hosmer-Lemeshow values of 0.35 and 0.31, respectively.</AbstractText>Sex predicts neither ROSC nor SURV in a swine model of prolonged VF.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
14,282 | Effects of isoproterenol and propranolol on the inducibility and frequency of ventricular fibrillation in patients with Brugada syndrome. | Isoproterenol (ISP), a beta-adrenergic agonist, suppresses arrhythmic storm in patients with sporadic Brugada syndrome (BS). However, the influence of ISP and the beta-adrenergic antagonist propranolol (PRO) on the inducibility and frequency of ventricular fibrillation (VF) in BS patients remains unclear.</AbstractText>Twenty-seven BS patients with induced VF>10s in a control state were enrolled. Electrophysiological stimulation (EPS) testing was performed during ISP and after PRO in selected patients. The inducibility and frequency of VF were compared. Dominant frequency (DF) was obtained by Fast Fourier transform from 4-s data (phase) and sequentially every 2s up to phase 5. ISP prevented induction of VF in 20 of 25 patients (80%). During ISP, 5 patients experienced induction of VF. ISP significantly influenced DF transition compared with the control state. DF gradually increased but was unchanged after the middle phase. PRO had no effect on incidence of induced VF in 5 patients; increased PRO induced VF in 5 (83.3%) of 6 patients who tested negative during ISP. After PRO, 10 patients experienced induction of VF. Thus, PRO significantly influenced DF transition. DF after PRO was higher than that in the corresponding phase in the control state.</AbstractText>ISP suppressed induction of VF and the increase of DF with time. PRO aggravated VF and accelerated DF.</AbstractText>Copyright © 2012 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
14,283 | Association between clinical outcome and antiarrhythmic treatment in heart failure patients who have atrial fibrillation upon admission to the hospital. | Atrial fibrillation (AF) and heart failure (HF) are associated with significant mortality and morbidity. We sometimes encounter patients who have AF upon admission to the hospital, but it spontaneously converts to sinus rhythm within several days (i.e. converter).</AbstractText>We examined the association between the outcome and types of strategy for AF treatment in converters.</AbstractText>From January 2000 to December 2005, we identified 95 converters (age 69 ± 12 years) presenting with worsening HF and AF upon admission, in which sinus rhythm was restored within 7 days without either electrical or pharmacological cardioversion. The patients were classified into three groups according to the antiarrhythmic drug (AAD) therapy used: class I AAD, class III AAD, and rate-control drug. The patients were followed for 36 ± 23 months.</AbstractText>The left ventricular ejection fraction (LVEF) significantly improved with conversion to sinus rhythm (38 ± 14% vs. 47 ± 13%, p<0.05). Those receiving class I AAD had a trend toward a well-preserved LVEF (50 ± 13%, n=35) as compared to those receiving class III AAD (43 ± 12%, n=24) or rate-control drug (47 ± 14%, n=36). In the patients receiving class I AAD, the rate of all-cause death increased 1.9-fold (p=0.009) compared to those receiving class III AAD, and 1.7-fold (p=0.010) compared to those taking rate-control drug. A hospitalization for HF was observed in 49 (52%) patients, however there was no significant difference in the rate of hospitalization among the three groups (p=0.890). Those receiving rate-control drugs had a 50% lower rate of the development of persistent AF than those taking class III AAD (p=0.019).</AbstractText>A rate-control strategy should be the primary approach for converters to reduce mortality and development of persistent AF.</AbstractText>Copyright © 2012 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
14,284 | Relationship between 24-h Holter recordings and clinical outcomes in patients with permanent atrial fibrillation. | This study aimed to test the hypothesis that the range of 24-h total heart beats (24 h-tHB) correlates with cardiac outcomes (cardiac death and incidence of hospitalization with heart failure) in patients with permanent atrial fibrillation (AF).</AbstractText>We divided 252 consecutive outpatients with permanent AF into 4 groups according to their 24 h-tHB and examined clinical outcomes. Initial 24 h-tHB at enrollment was significantly associated with patient characteristics including age, sex, presence of structural heart diseases, and left ventricular ejection fraction (EF). The cumulative incidence of heart failure was high in the lowest 24 h-tHB group compared with other groups and significantly different from the highest one (23.9% vs. 7.2% at 5 years, p=0.0074). Multivariate analysis showed that 24 h-tHB<100,000 was associated with cardiac events [hazard ratio, 2.45; 95% confidence interval (CI), 1.09-5.49; p=0.03), along with structural heart disease (hazard ratio, 9.81; 95% CI, 3.34-28.83; p=0.0001) and EF (hazard ratio, 0.97; 95% CI, 0.94-0.99; p=0.002).</AbstractText>Surprisingly, low but not high heart rate was significantly associated with higher incidence of heart failure in Japanese patients. This finding should be further evaluated in future prospective studies.</AbstractText>Copyright © 2012 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
14,285 | Prediction of surgical outcome after aortic valve replacement. | Aortic valve replacement has some major adverse outcomes. For these, the predictors need identification.</AbstractText>This was a retrospective file study of 1000 consecutive patients who underwent AVR for degenerative aortic valve disease. Twenty-five preoperative and 5 peroperative factors were screened by a univariate Fisher-exact analysis. The predictors were identified in a second step by logistic regression multivariate analysis.</AbstractText>Five hundred thirty patients were male. The mean age was 75 (71-77) years and 610 also underwent CABG. For hospital mortality, need for urgent aortic valve replacement (p < 0.001) was the dominant predictor. Need for digitalis (p = 0.002) and age > 80 (p = 0.005) followed. For postoperative congestive heart failure, need for urgent aortic valve replacement was also dominant (p <0.001). Atrial fibrillation (p = 0.001,) and ejection fraction < 50% (p = 0.055) were less important. For ventricular arrhythmia, previous infarction (p = 0.025) and ejection fraction < 50% (p = 0.032) were identified. For bleeding, concomitant CABG (p = 0.046) and chronic obstructive pulmonary disease were identified. For thromboembolic events only an ejection fraction < 50% (p = 0.027) was identified.</AbstractText>Need for urgent aortic valve replacement is the dominant predictor for postoperative mortality and congestive heart failure. Once a degenerative aortic valve disease becomes symptomatic, prompt referral could prevent the development for need for urgent surgery, with all its adverse postoperative consequences.</AbstractText> |
14,286 | Early repolarisation: controversies and clinical implications. | Early repolarisation was previously considered a benign variant but in recent years has emerged as a marker of risk for sudden death. In part, this appears to reflect a change in the definition. ECG territory, degree of J-point elevation and ST-segment morphology are associated with different degrees of risk for subsequent ventricular arrhythmia. At present the dataset is insufficient to allow risk stratification in asymptomatic individuals and further epidemiological and mechanistic research is required. |
14,287 | Effect of ramipril on the electrophysiological characteristics of ventricular myocardium after myocardial infarction in rabbits. | The current study aims to explore the effect of ramipril on the occurrence of ventricular arrhythmias and its possible mechanism after myocardial infarction (MI) in rabbits.</AbstractText>A total of 24 rabbits were divided into three groups: the sham operation group (SHAM), the MI group, and the ramipril group (RAM). All groups were subjected to thoracotomy under sterile conditions; the MI and RAM groups underwent ligation of the left anterior descending coronary artery. On the second day after surgery, the RAM group was given ramipril (1 mg/kg per day). The rabbits in each group were fed for 12 weeks. The monophasic action potentials of the epicardium, mid-myocardium and endocardium in each group were, respectively, recorded before the MI and at 12 weeks after the MI. Meanwhile, the episodes of ventricular tachycardia or fibrillation (VT/VF) induced by procedure stimulations were counted, and the changes in L-type Ca flux (Ica-L) were recorded by means of the whole-cell patch-clamp technique.</AbstractText>The episodes of VT/VF were decreased in the RAM group after MI. At 12 weeks after MI, the transmural dispersion of repolarization (TDR) in the MI group was prolonged significantly compared with the SHAM and RAM groups. The density of Ica-L in the MI group was significantly lower than that any other group.</AbstractText>Ramipril manifestly decreases the incidence of VT/VF after MI in rabbits, and the mechanism may be associated with its inhibitory effect on electrical remodeling after MI.</AbstractText> |
14,288 | Prevalence of prominent J waves in patients presenting with ventricular fibrillation without structural heart disease: a single-center study. | Association between sudden cardiac arrest and early repolarization (QRS slurring in the inferolateral leads) has drawn recent attention. We retrospectively assessed the prevalence of electrocardiographic J waves in 19 men aged 46.5±13.7 years who, between 1979 and 2011, were resuscitated after cardiac arrest due to ventricular fibrillation. There was no structural heart disease in this group. The J wave is an elevation of the QRS-ST junction of at least 0.1mV from baseline in the inferior or lateral leads, manifested as QRS slurring or notching. Eleven patients (age, 37.3±13.9 years) showed J waves in the inferior leads (n=8) or in both the inferior and lateral leads (n=3). Brugada syndrome was diagnosed in 5 patients (age, 46.4±15.7 years). The QRS complex was normal in the remaining 3 patients (age, 44.3±9.5 years). Ventricular fibrillation was induced by programmed ventricular stimulation with up to 3 extrastimuli from the right ventricular apex or outflow tract in 7 of the 10 J-wave syndrome patients tested, in all 5 Brugada syndrome patients, and in all 3 patients with a normal electrocardiogram. There appears to be an increased prevalence of J-wave syndrome among patients with a history of idiopathic ventricular fibrillation. |
14,289 | Determinants of atrial fibrillation in an animal model of obesity and acute obstructive sleep apnea. | Obesity and obstructive sleep apnea (OSA) are risk factors for atrial fibrillation (AF), but the underlying mechanisms are poorly understood.</AbstractText>The purpose of this study was to assess the mechanisms underlying AF promotion by obesity and OSA in rat models.</AbstractText>Zucker obese rats (ORs) and lean rats (LRs) were intubated and ventilated with air and 2% isoflurane. OSA was mimicked by stopping the ventilator and closing the airway for 40 seconds. For nonobstructive control periods, the protocol was repeated with an open airway. Fifteen seconds after apnea onset, AF susceptibility was tested with 6 atrial burst pacing cycles (25 Hz, 3 seconds, 1-second intercycle pauses).</AbstractText>AF was not inducible in ORs or LRs at baseline or in nonobstructive control periods. AF was induced in 24 of 28 ORs (85.7%) vs 5 of 18 LRs (27.8%) during obstructive apnea (P <.001). Negative intrathoracic pressure generation (esophageal pressure monitoring) was substantial during obstructive apnea. Echocardiography showed left ventricular hypertrophy with diastolic dysfunction in ORs. Obstructive apnea caused acute left atrial (LA) dilation, increasing LA diameter significantly more in ORs than in LRs. To clarify AF mechanisms, 24 AF-inducible ORs were divided into 4 groups: saline (n = 5), pharmacologic autonomic blockade (n = 7), respiratory muscle paralysis with rocuronium (n = 6), and inferior vena cava (IVC) balloon occlusion to unload the LA (n = 6). Balloon catheter-induced IVC occlusion prevented LA distension during obstructive apnea, leading to 83.3% AF prevention (P <.05). Rocuronium also was protective (66.7%), but autonomic blockade had smaller effects (42.9% prevention).</AbstractText>Obesity and acute obstructive apnea interacted to promote AF in this model. Forced inspiration-induced acute LA distension related to diastolic dysfunction may be an important component of the arrhythmogenic substrate for AF during OSA episodes in obese patients.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
14,290 | Usefulness of SUM of ST-segment elevation on electrocardiograms (limb leads) for predicting in-hospital complications in patients with stress (takotsubo) cardiomyopathy. | Although the prognosis of patients with stress (takotsubo) cardiomyopathy is relatively favorable, serious complications occur in some patients. It is generally accepted that electrocardiography is an essential tool for the diagnosis of stress cardiomyopathy, with findings highly suggestive of the characteristics of myocardial damage. We tested the hypothesis that the quantitative analysis of electrocardiograhic changes can predict complications in stress cardiomyopathy. The study subjects were 85 patients with stress cardiomyopathy. A total of 34 patients developed ≥1 in-hospital complications (heart failure, intraventricular pressure gradient [>30 mm Hg], cardiogenic shock, ventricular tachycardia/fibrillation, and embolism). Patients with complications were likely to have a higher heart rate (96 ± 25 vs 76 ± 17 beats/min, p <0.001), larger sum of ST-segment elevation in 12 leads (median 10.5 mm; interquartile range 5.0 to 17.5 vs 3.0 mm, interquartile range 0 to 7.0; p <0.001) and extension of ST-segment elevation to limb leads (50% vs 12%, p <0.001) than those without complications. Multivariate logistic regression analysis identified heart rate (odds ratio 1.05, 95% confidence interval 1.02 to 1.07, p = 0.001) and sum of ST-segment elevation in 12 leads (odds ratio 1.24, 95% confidence interval 1.11 to 1.39, p <0.001) as significant and independent predictors of complications. Receiver operating characteristic analysis selected 5.5 mm as the best cutoff value of sum of ST-segment elevation in 12 leads for the prediction of complications, with a sensitivity and specificity of 74% and 73%, respectively, and area under the curve of 0.81 (95% confidence interval 0.72 to 0.90, p <0.001). The results suggest that the extent and magnitude of ST-segment elevation on the electrocardiogram are potentially useful predictors of in-hospital complications in patients with stress cardiomyopathy. |
14,291 | Dexrazoxane provided moderate protection in a catecholamine model of severe cardiotoxicity. | Positive effects of dexrazoxane (DEX) in anthracycline cardiotoxicity have been mostly assumed to be associated with its iron-chelating properties. However, this explanation has been recently questioned. Iron plays also an important role in the catecholamine cardiotoxicity. Hence in this study, the influence of DEX on a catecholamine model of acute myocardial infarction (100 mg/kg of isoprenaline by subcutaneous injection) was assessed: (i) the effects of an intravenous dose of 20.4 mg/kg were analyzed after 24 h, (ii) the effects were monitored continuously during the first two hours after drug(s) administration to examine the mechanism(s) of cardioprotection. Additional in vitro experiments on iron chelation/reduction and influence on the Fenton chemistry were performed both with isoprenaline/DEX separately and in their combination. DEX partly decreased the mortality, reduced myocardial calcium overload, histological impairment, and peripheral haemodynamic disturbances 24 h after isoprenaline administration. Continuous 2 h experiments showed that DEX did not influence isoprenaline induced atrioventricular blocks and had little effect on the measured haemodynamic parameters. Its protective effects are probably mediated by inhibition of late myocardial impairment and ventricular fibrillation likely due to inhibition of myocardial calcium overload. Complementary in vitro experiments suggested that iron chelation properties of DEX apparently did not play the major role. |
14,292 | Clinical impact of atrial fibrillation in patients with pulmonary hypertension. | Pulmonary hypertension (PH) is associated with progressive impairment of right ventricular function, reduced exercise capacity and a poor prognosis. Little is known about the prevalence, clinical manifestation and impact of atrial fibrillation (AF) on cardiac function in PH.</AbstractText>In a four year single-centre retrospective analysis 225 patients with confirmed PH of various origins were enrolled to investigate the prevalence of AF, and to assess the clinical manifestation, 6-minute walk distance, NT-proBNP levels, echocardiographic parameters and hemodynamics obtained by right heart catheterization in PH with AF.</AbstractText>AF was prevalent in 31.1%. In patients with PH and AF, parameters of clinical deterioration (NYHA/WHO functional class, 6-minute walk distance, NT-proBNP levels) and renal function were significantly compromised compared to patients with PH and sinus rhythm (SR). In the total PH cohort and in PH not related to left heart disease occurrence of AF was associated with an increase of right atrial pressure (RAP) and right atrial dilatation. While no direct association was found between pulmonary artery pressure (PAP) and AF in these patients, right ventricular function was reduced in AF, indicating more advanced disease. In PH due to left heart failure the prevalence of AF was particularly high (57.7% vs. 23.1% in other forms of PH). In this subgroup, left atrial dilatation, increase of pulmonary capillary wedge pressure, PAP and RAP were more pronounced in AF than in SR, suggesting that more marked backward failure led to AF in this setting.</AbstractText>PH is associated with increased prevalence of AF. Occurrence of AF in PH indicates clinical deterioration and more advanced disease.</AbstractText> |
14,293 | Atrioventricular nodal ablation in atrial fibrillation: a meta-analysis of biventricular vs. right ventricular pacing mode. | For patients with refractory atrial fibrillation (AF) undergoing atrioventricular nodal ablation (AVNA), initial single-chamber right ventricular (RV)-only pacing is standard. Given the deleterious effects of chronic RV-only pacing, the impact of an initial biventricular (BiV) pacing strategy post-ablation is of interest.</AbstractText>We conducted a meta-analysis to determine the effect of BiV vs. RV-only pacing in patients undergoing AVNA for refractory atrial fibrillation. A search of multiple electronic databases identified 921 reports, which included four randomized controlled trials (n = 534). Mean New York Heart Association (NYHA) class was 2.3 and mean left ventricular ejection fraction (LVEF) was 44%. When compared with RV-only pacing, BiV pacing was not associated with reduced mortality [risk ratio 0.85, 95% confidence interval (CI) 0.40-1.82, P = 0.68]. In three studies comprised of patients with left ventricular systolic dysfunction (mean EF 41 ± 3%), BiV pacing demonstrated a non-significant reduction in cardiac mortality (risk ratio 0.59, 95% CI 0.25-1.39; P = 0.23). Compared with RV-only pacing, BiV pacing was associated with significant improvement in symptoms [Minnesota Living with Heart Failure Questionnaire (MLWHFQ) 2.72 points fewer, 95% CI 1.45-3.99] and increased LVEF (+2.6%, 95% CI 1.69-3.44), but no significant change in 6 min walk distance (6MWD) (5.02 ms more, 95% CI -1.56 to 11.59; P = 0.13).</AbstractText>In patients with refractory AF undergoing AVNA, BiV pacing was not associated with significantly improved survival when compared with RV-only pacing. A modest, but significant improvement in structural and functional response to BiV pacing was observed.</AbstractText> |
14,294 | Safety of flecainide. | Flecainide is a class Ic antiarrhythmic agent that has an important role as part of rhythm control strategies in patients with atrial fibrillation (AF). Early clinical data on the use of flecainide showed an increase in arrhythmias and mortality compared with placebo in patients with a previous myocardial infarction and asymptomatic or mildly symptomatic ventricular arrhythmias. These findings only apply to a specific group of patients with left ventricular dysfunction and ischaemic heart disease, but had a negative impact on the use of class Ic antiarrhythmics across all indications and patient groups. The aim of this review was to evaluate the available safety data for flecainide in the literature and to assess its current use in patients with AF. Current European guidelines now recommend the use of flecainide in carefully selected groups of patients with AF who do not have structural heart disease. This includes for the cardioversion of recent-onset AF, pretreatment prior to direct current cardioversion, out-of-hospital acute oral therapy ('pill-in-the-pocket' approach) and for the ongoing maintenance of sinus rhythm. Potential cardiac adverse effects of flecainide include proarrhythmia, conduction abnormalities and negative inotropic effects. Dizziness is the most frequent non-cardiac side effect, followed by blurred vision and difficulty focusing; these are almost all mild, transient and tolerable. Data from recent clinical trials in patients with supraventricular arrhythmias suggest that flecainide has a good tolerability profile in groups of appropriately selected patients. Caution is required when using flecainide in patients with renal dysfunction, and there are a number of drug interactions, but these are well documented and manageable. Overall, flecainide is a good choice for the pharmacological management of AF. It has a good safety record and low incidence of adverse effects, rare end-organ toxicity and a low risk of ventricular proarrhythmia. To ensure that the benefits of treatment outweigh any potential risks, careful patient selection and monitoring is required. |
14,295 | Catheter ablation of ventricular fibrillation triggers and electrical storm. | Ventricular fibrillation (VF) and electrical storm remain challenging conditions to manage despite the availability of various treatment modalities. Insertion of an implantable cardioverter defibrillator (ICD) remains the gold standard method for lowering the risk of sudden cardiac death in patients deemed to be at greatest risk of ventricular arrhythmias. However, ICDs do not alter the underlying substrate responsible for the arrhythmic events and a significant proportion of patients with ICDs may experience VF storm which may be life threatening and difficult to control with medication. Catheter ablation (CA) of the triggers or abnormal electrical substrate responsible for VF storm is an important treatment option in rare cases. In this article, we present an overview of the current theories underlying the mechanisms of VF and discuss how the technique of CA may be used to treat the triggers of VF and electrical storm. We review the literature on outcomes in patients who have undergone CA for VF in a variety of different settings, including those with structural heart disease and structurally normal hearts (e.g. patients with inherited arrhythmogenic diseases and idiopathic VF) and discuss the future directions in this field. |
14,296 | Embozene™ microspheres induced nonreperfused myocardial infarction in an experimental swine model. | To develop a magnetic resonance imaging (MRI) compatible, percutaneous technique for the generation of nonreperfused myocardial infarct (MI).</AbstractText>Modeling nontreated MI has major importance in the development and preclinical testing of new therapeutic strategies for patients missing the time window suitable for revascularization following MI.</AbstractText>In 31 male swine, nonreperfused MI was generated by permanent occlusion of either the LAD or LCX coronary artery using 900 μm Embozene™ microspheres. Animals were monitored for 90 min postocclusion. Surviving animals were followed up for 2 (n = 6), 4 (n = 6), 14 (n = 6), or 56 (n = 6) days. At the end of the planned study session, contrast enhanced MRI, triphenyl-tetrazolium-chloride staining, and microscopic histopathology were carried out.</AbstractText>The mortality rate in this study was 22.6%. Intraoperative arrhythmias occurred in 14 cases: premature ventricular complexes with (5) or without (3) ventricular tachycardia, 2nd degree atrio-ventricular block (1), and ventricular fibrillation (6). MRI, TTC, and histology confirmed the existence of MI in every case. Macroscopic pathology showed that the microspheres caused a practically total occlusion at the epicardial level of the coronary artery. Multiple infarcts were detected in one case, probably due to unintentional reflux of the microspheres. Microspheres retained in the coronary arteries did not cause any MRI artifact.</AbstractText>The generation of nonreperfused MI is feasible by percutaneous injection of Embozene into the coronary artery system. The MI model thus obtained is suitable for the purposes of MRI experiments.</AbstractText>Copyright © 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
14,297 | [A 59 year-old patient with acute anterolateral myocardial infarction, complicated by cardiogenic shock, with chest wall deformity caused by Heine-Medin disease]. | We report a case of a 59 year-old patient in a condition of acute myocardial infarction with ST elevation, in a cardiogenic shock, with multiple cardiac arrests in mechanism of ventricular fibrillation with a significant chest wall deformity caused by Heine-Medin disease in childhood. To our knowledge, this is the first case report of a patient in critical condition with a considerable pectus deformity after poliomyelitis who needed to undergo cardiovascular angioplasty. Although severe patient's condition and numerous difficulties during percutaneous coronary intervention, therapy was successful. |
14,298 | Oesophageal cancer with myocardial metastasis complicated by ventricular fibrillation: the role of echocardiography. | Myocardial metastasis from oesophageal cancer is very rare, and is usually detected as part of widespread metastases in the terminal stage. It is rare to detect a solitary metastasis. We present a case of solitary myocardial metastasis from distal oesophagus complicated by ventricular fibrillation. |
14,299 | Controlled pauses at the initiation of sodium nitroprusside-enhanced cardiopulmonary resuscitation facilitate neurological and cardiac recovery after 15 mins of untreated ventricular fibrillation. | A multipronged approach to improve vital organ perfusion during cardiopulmonary resuscitation that includes sodium nitroprusside, active compression-decompression cardiopulmonary resuscitation, an impedance threshold device, and abdominal pressure (sodium nitroprusside-enhanced cardiopulmonary resuscitation) has been recently shown to increase coronary and cerebral perfusion pressures and higher rates of return of spontaneous circulation vs. standard cardiopulmonary resuscitation. To further reduce reperfusion injury during sodium nitroprusside-enhanced cardiopulmonary resuscitation, we investigated the addition of adenosine and four 20-sec controlled pauses spread throughout the first 3 mins of sodium nitroprusside-enhanced cardiopulmonary resuscitation. The primary study end point was 24-hr survival with favorable neurologic function after 15 mins of untreated ventricular fibrillation.</AbstractText>Randomized, prospective, blinded animal investigation.</AbstractText>Preclinical animal laboratory.</AbstractText>Thirty-two female pigs (four groups of eight) 32±2 kg.</AbstractText>After 15 mins of untreated ventricular fibrillation, isoflurane-anesthetized pigs received 5 mins of either standard cardiopulmonary resuscitation, sodium nitroprusside-enhanced cardiopulmonary resuscitation, sodium nitroprusside-enhanced cardiopulmonary resuscitation+adenosine, or controlled pauses-sodium nitroprusside-enhanced cardiopulmonary resuscitation+adenosine. After 4 mins of cardiopulmonary resuscitation, all animals received epinephrine (0.5 mg) and a defibrillation shock 1 min later. Sodium nitroprusside-enhanced cardiopulmonary resuscitation-treated animals received sodium nitroprusside (2 mg) after 1 min of cardiopulmonary resuscitation and 1 mg after 3 mins of cardiopulmonary resuscitation. After 1 min of sodium nitroprusside-enhanced cardiopulmonary resuscitation, adenosine (24 mg) was administered in two groups.</AbstractText>A veterinarian blinded to the treatment assigned a cerebral performance category score of 1-5 (normal, slightly disabled, severely disabled but conscious, vegetative state, or dead, respectively) 24 hrs after return of spontaneous circulation. Sodium nitroprusside-enhanced cardiopulmonary resuscitation, sodium nitroprusside-enhanced cardiopulmonary resuscitation+adenosine, and controlled pauses-sodium nitroprusside-enhanced cardiopulmonary resuscitation+adenosine resulted in a significantly higher 24-hr survival rate compared to standard cardiopulmonary resuscitation (7 of 8, 8 of 8, and 8 of 8 vs. 2 of 8, respectively p<.05). The mean cerebral performance category scores for standard cardiopulmonary resuscitation, sodium nitroprusside-enhanced cardiopulmonary resuscitation, sodium nitroprusside-enhanced cardiopulmonary resuscitation+adenosine, or controlled pauses-sodium nitroprusside-enhanced cardiopulmonary resuscitation+adenosine were 4.6±0.7, 3±1.3, 2.5±0.9, and 1.5±0.9, respectively (p<.01 for controlled pauses-sodium nitroprusside-enhanced cardiopulmonary resuscitation+adenosine compared to all other groups).</AbstractText>Reducing reperfusion injury and maximizing circulation during cardiopulmonary resuscitation significantly improved functional neurologic recovery after 15 mins of untreated ventricular fibrillation. These results suggest that brain resuscitation after prolonged cardiac arrest is possible with novel, noninvasive approaches focused on reversing the mechanisms of tissue injury.</AbstractText> |
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