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12,800 | Ventricular fibrillation and tachycardia classification using a machine learning approach. | Correct detection and classification of ventricular fibrillation (VF) and rapid ventricular tachycardia (VT) is of pivotal importance for an automatic external defibrillator and patient monitoring. In this paper, a VF/VT classification algorithm using a machine learning method, a support vector machine, is proposed. A total of 14 metrics were extracted from a specific window length of the electrocardiogram (ECG). A genetic algorithm was then used to select the optimal variable combinations. Three annotated public domain ECG databases (the American Heart Association Database, the Creighton University Ventricular Tachyarrhythmia Database, and the MIT-BIH Malignant Ventricular Arrhythmia Database) were used as training, test, and validation datasets. Different window sizes, varying from 1 to 10 s were tested. An accuracy (Ac) of 98.1%, sensitivity (Se) of 98.4%, and specificity (Sp) of 98.0% were obtained on the in-sample training data with 5 s-window size and two selected metrics. On the out-of-sample validation data, an Ac of 96.3% ± 3.4%, Se of 96.2% ± 2.7%, and Sp of 96.2% ± 4.6% were obtained by fivefold cross validation. The results surpass those of current reported methods. |
12,801 | Application of CRT-D in a Marfan syndrome patient with chronic heart failure accompanied by ventricular tachycardia and ventricular fibrillation. | Marfan syndrome is a systemic connective tissue disease that could affect the cardiovascular system and eventually lead to heart enlargement and heart failure with high mortality, mainly due to progressive heart failure and/or sudden cardiac death caused by malignant arrhythmia. Here we report that a patient received a cardiac resynchronization therapy-defibrillator (CRT-D) with a pre-monitor function for heart failure and experienced obvious improvements in his cardiac function. Postoperative follow-up showed that the patient had reduced morbidity and hospitalization for heart failure, and also experienced improved quality of life. |
12,802 | Feasibility and cardiac safety of inhaled xenon in combination with therapeutic hypothermia following out-of-hospital cardiac arrest. | Preclinical studies reveal the neuroprotective properties of xenon, especially when combined with hypothermia. The purpose of this study was to investigate the feasibility and cardiac safety of inhaled xenon treatment combined with therapeutic hypothermia in out-of-hospital cardiac arrest patients.</AbstractText>An open controlled and randomized single-centre clinical drug trial (clinicaltrials.gov NCT00879892).</AbstractText>A multipurpose ICU in university hospital.</AbstractText>Thirty-six adult out-of-hospital cardiac arrest patients (18-80 years old) with ventricular fibrillation or pulseless ventricular tachycardia as initial cardiac rhythm.</AbstractText>Patients were randomly assigned to receive either mild therapeutic hypothermia treatment with target temperature of 33°C (mild therapeutic hypothermia group, n=18) alone or in combination with xenon by inhalation, to achieve a target concentration of at least 40% (Xenon+mild therapeutic hypothermia group, n=18) for 24 hours. Thirty-three patients were evaluable (mild therapeutic hypothermia group, n=17; Xenon+mild therapeutic hypothermia group, n=16).</AbstractText>Patients were treated and monitored according to the Utstein protocol. The release of troponin-T was determined at arrival to hospital and at 24, 48, and 72 hours after out-of-hospital cardiac arrest. The median end-tidal xenon concentration was 47% and duration of the xenon inhalation was 25.5 hours. The frequency of serious adverse events, including inhospital mortality, status epilepticus, and acute kidney injury, was similar in both groups and there were no unexpected serious adverse reactions to xenon during hospital stay. In addition, xenon did not induce significant conduction, repolarization, or rhythm abnormalities. Median dose of norepinephrine during hypothermia was lower in xenon-treated patients (mild therapeutic hypothermia group=5.30 mg vs Xenon+mild therapeutic hypothermia group=2.95 mg, p=0.06). Heart rate was significantly lower in Xenon+mild therapeutic hypothermia patients during hypothermia (p=0.04). Postarrival incremental change in troponin-T at 72 hours was significantly less in the Xenon+mild therapeutic hypothermia group (p=0.04).</AbstractText>Xenon treatment in combination with hypothermia is feasible and has favorable cardiac features in survivors of out-of-hospital cardiac arrest.</AbstractText> |
12,803 | Inverted Takotsubo cardiomyopathy--clinicopathologic correlation. | We report the case of a 34-year-old woman who presented after a witnessed out-of-hospital arrest. Initial cardiac rhythm at the time of resuscitation was ventricular fibrillation. Subsequently in hospital, she developed further episodes of polymorphic ventricular tachycardia and ventricular fibrillation. Urgent echocardiography showed features suggestive of an inverted takotsubo cardiomyopathy. Twenty-four hours after admission, there was a further episode of polymorphic ventricular tachycardia from which the patient could not be resuscitated. An autopsy confirmed the cause of death as inverted takotsubo cardiomyopathy. We present the pathological findings from the postmortem autopsy. |
12,804 | [Effect of autologous platelet-rich plasma on heart infarction in sheep]. | Myocardial infarction is the most common cause of congestive heart failure. The objective of this work is to evaluate, in experimental animals, morphological and histological effects of the implantation of autologous platelet-rich plasma in infarcted heart sheep.</AbstractText>Twenty-four ewes were used, they were surgically infarcted through left thoracotomy and two coronary arteries were ligated (first and second diagonal). After coronary artery ligation three sheep died of ventricular fibrillation. Three weeks after coronary ligation, sheep were reoperated through median sternotomy. Normal saline solution was injected in the infarcted zone in 6 of them (control group) whereas platelet gel was injected in 15 of them. All sheep were euthanized at 9 weeks of evolution of the second surgery.</AbstractText>Noteworthy is the formation of new vessels in hematoxylin-eosin-stained sections and factor viii in plasma rich in growth-factors (PRGF)-treated hearts.</AbstractText>Injection of platelet growth factors, PRGF, in previously infarcted sheep hearts promotes mitogenesis and angiogenesis. The use of autologous PRGF is simple and safe, causing no toxicity or immune-inflammatory reactions.</AbstractText>Copyright © 2012 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.</CopyrightInformation> |
12,805 | ECG abnormalities and stroke incidence. | In this review, the authors discuss the role of ECG in prediction of stroke. ECG plays an important role in detection of several stroke risk factors/predictors including atrial fibrillation and left ventricular hypertrophy; both are components of the Framingham Stroke Risk Score. Multiple other ECG traits have also emerged as potential predictors of stroke, namely cardiac electrical/structural remodeling--Q wave, QRS/QT duration, bundle blocks, P wave duration/amplitude/dispersion, other waveform angles and slopes; higher automaticity--ectopic beats; and re-entry--atrial tachyarrhythmia; and higher vulnerability to arrhythmia--heart rate and its variability. Most of these predictors are not ready for prime time yet; however, further research focusing on their role in risk stratification and prevention of stroke may be useful. In this article, the authors discuss the prevalence, mechanisms and clinical applications of traditional and novel ECG markers in the prevention and treatment of stroke. |
12,806 | Cardiac MRI in the treatment of arrhythmias. | Catheter-based ablation techniques are extensively used for the treatment of atrial and ventricular arrhythmias. Preprocedural cardiac MRI is valuable for the management of these patients due to its ability to provide high-resolution anatomic mapping and tissue characterization in the absence of ionizing radiation. Delayed enhancement imaging can be used to localize the arrhythmia substrate within the chamber of interest prior to the procedure. There is growing evidence that delayed enhancement cardiac MRI may be useful in patients with atrial fibrillation in terms of treatment decisions and assessment of ablation efficacy. |
12,807 | Modulation of regional dispersion of repolarization and T-peak to T-end interval by the right and left stellate ganglia. | Left stellate or right stellate ganglion stimulation (LGSG or RSGS, respectively) is associated with ventricular tachyarrhythmias; however, the electrophysiological mechanisms remain unclear. We assessed 1) regional dispersion of myocardial repolarization during RSGS and LSGS and 2) regional electrophysiological mechanisms underlying T-wave changes, including T-peak to T-end (Tp-e) interval, which are associated with ventricular tachyarrhythmia/ventricular fibrillation. In 10 pigs, a 56-electrode sock was placed around the heart, and both stellate ganglia were exposed. Unipolar electrograms, to asses activation recovery interval (ARI) and repolarization time (RT), and 12-lead ECG were recorded before and during RSGS and LSGS. Both LSGS and RSGS increased dispersion of repolarization; with LSGS, the greatest regional dispersion occurred on the left ventricular (LV) anterior wall and LV apex, whereas with RSGS, the greatest regional dispersion occurred on the right ventricular posterior wall. Baseline, LSGS, and RSGS dispersion correlated with Tp-e. The increase in RT dispersion, which was due to an increase in ARI dispersion, correlated with the increase in Tp-e intervals (R(2) = 0.92 LSGS; and R(2) = 0.96 RSGS). During LSGS, the ARIs and RTs on the lateral and posterior walls were shorter than the anterior LV wall (P < 0.01) and on the apex versus base (P < 0.05), explaining the T-wave vector shift posteriorly/inferiorly. RSGS caused greater ARI and RT shortening on anterior versus lateral or posterior walls (P < 0.01) and on base versus apex (P < 0.05), explaining the T-wave vector shift anteriorly/superiorly. LSGS and RSGS cause differential effects on regional myocardial repolarization, explaining the ECG T-wave morphology. Sympathetic stimulation, in line with its proarrhythmic effects, increases Tp-e interval, which correlates with increases in myocardial dispersion of repolarization. |
12,808 | Successful treatment of mobile right atrial thrombus and acute pulmonary embolism with intravenous tissue plasminogen activator. | An 89-year-old woman came with symptoms of progressively worsening dyspnoea at rest over the preceding week. She was normotensive, had elevated jugular venous pressure and clear lungs. ECG revealed atrial fibrillation with the rapid ventricular rate. Labs were significant for markedly elevated pro-brain natriuretic peptide of 43,000 pg/mL and troponin-T of 1 ng/mL. An urgent 2D echocardiogram was obtained, which revealed the severely dilated right atrium and a large linear mobile mass in the right atrium consistent with a thrombus. An emergent CT scan revealed multiple bilateral pulmonary emboli. She received intravenous tissue plasminogen activator. Repeat echocardiogram performed 6 h later showed no evidence of the right atrial thrombus. She was subsequently maintained on intravenous heparin and transitioned to Coumadin. Early recognition of this rare but potentially fatal complication is important as prompt treatment measures can help in preventing life-threatening complications of the right atrial thrombus. |
12,809 | Antitachycardia pacing for very fast ventricular tachycardia and low-energy shock for ventricular arrhythmias in patients with implantable defibrillators. | Implantable cardioverter-defibrillator therapy in the form of high-energy shock (HES) is associated with adverse effects. This study evaluated an alternative therapy to HES, including antitachycardia pacing (ATP) for very fast ventricular tachycardia (VFVT) and low-energy shock (LES) ≤5 J for ventricular tachycardia (VT) of any cycle length (CL). This multicenter study recruited 602 patients with standard indications for an implantable cardioverter-defibrillator. Programming was standardized into 3 zones: (1) ventricular fibrillation (VF) CL of <200 ms treated with HES; (2) VFVT defined within the VF zone (CL, 200 to 250 ms) treated with 2 ATP bursts, LES, and HES; and (3) fast ventricular tachycardia (CL, 251 to 320 ms) and slow VT (CL, >320 ms) treated with 3 ATP bursts, LES, and HES. The primary end point was ATP and LES efficacy and safety. After a mean follow-up of 19 ± 8 months, 2,815 device activations were recorded in 152 patients. Of 67 VFVT episodes, 34 reverted with combined ATP and LES (success rate 50.7%) with first and second ATPs successful in 36% and 13.8%, respectively. LES was used in 39 fast ventricular tachycardia and 60 slow VT episodes with success rates of 53.8% and 73.3%, respectively. Syncope occurred in 19.4%, 16.2%, and 1% of episodes because of VFVT, VF, and VT CL >250 ms, respectively. In conclusion, tiered ATP and LES therapy terminates >50% of VFVT episodes (CL, 200 to 250 ms), which otherwise would fall within the VF zone and be treated exclusively with HES. LES is efficacious and safe in patients with VT CL >250 ms with extremely low syncope rates. Limitation of ATP to a single burst in VFVT is recommended to minimize syncope. |
12,810 | Should paroxysmal atrial fibrillation be treated during cardiac surgery? | Randomized controlled trials of permanent atrial fibrillation ablation surgery have shown improved outcomes compared with control patients undergoing concomitant cardiac surgery. Little has been reported regarding patients with paroxysmal atrial fibrillation. We hypothesized that treating paroxysmal atrial fibrillation during cardiac surgery would not adversely affect the perioperative risk and would improve the midterm outcomes.</AbstractText>From April 2004 to June 30 2012, 4947 patients (excluding those with transcatheter aortic valve implants, left ventricular assist devices, trauma, transplantation, and isolated atrial fibrillation surgery) underwent cardiac surgery, and 1150 (23%) had preoperative atrial fibrillation. Of these, 552 (48%) had paroxysmal atrial fibrillation. Three groups were compared using propensity score matching: treated (n = 423, 77%), untreated (n = 129, 23%), and no atrial fibrillation (n = 3797).</AbstractText>The treated patients had 30-day mortality similar to that of the untreated patients and those without atrial fibrillation. They had fewer perioperative complications (26% vs 46%, P = .001), greater freedom from atrial fibrillation at the last follow-up visit (81% vs 60%, P = .007), and lower mortality (hazard ratio 0.47, P = .007) compared with the untreated patients. Compared with those without atrial fibrillation, the treated patients had fewer perioperative complications (25% vs 48%, P < .001), lower freedom from atrial fibrillation at the last follow-up visit (84% vs 93%, P = .001), and similar mortality.</AbstractText>Concomitant surgical ablation of paroxysmal atrial fibrillation was not associated with increased perioperative risk. The treated patients had greater late freedom from atrial fibrillation and midterm survival compared with the untreated patients, and similar midterm survival compared with the patients without atrial fibrillation. These results suggest that paroxysmal atrial fibrillation warrants treatment consideration in select patients undergoing cardiac surgery.</AbstractText>Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
12,811 | Impact of atrial fibrillation-induced tachycardiomyopathy in patients undergoing pulmonary vein isolation. | Atrial fibrillation (AF) is a recognized treatable cause of tachycardiomyopathy (TMP), with class IIb indication for catheter ablation (CA). The aim of this study is to analyze the prevalence, clinical characteristics and effect of CA in patients with TMP and to evaluate TMP as a prognostic factor for AF recurrence in these patients (TMP group), compared to controls with normal left ventricular ejection fraction (LVEF) and patients with heart failure due to structural cardiomyopathy (HF group).</AbstractText>The study groups included 659 consecutive patients undergoing CA between 2003 and 2011: TMP group (n = 61), HF group (n = 36) and control group (n = 562). Compared to controls, patients with TMP were younger, had a shorter AF course and more often had persistent AF. Regarding echocardiographic parameters, the TMP group had lower LVEF (40% vs. 62%, P < 0.05), larger left atrial diameter (LAD: 46 vs. 41 mm, P < 0.05) and LV end-diastolic diameter (LVEDD: 55 vs. 51 mm, P < 0.05) compared to controls, with significant improvement at six-month follow-up, including those patients with AF recurrence. The probability of being arrhythmia-free did not differ between the TMP group and the other groups after a first or last procedure. The only independent predictor of AF recurrence was LAD.</AbstractText>Patients with tachycardiomyopathy secondary to AF benefit from CA, with a significant improvement in LVEF, LVEDD and LAD. The outcome after CA of this group did not differ from patients with no structural cardiomyopathy.</AbstractText>© 2013.</CopyrightInformation> |
12,812 | Perioperative cardiopulmonary arrest competencies. | Although basic life support skills are not often needed in the surgical setting, it is crucial that surgical team members understand their roles and are ready to intervene swiftly and effectively if necessary. Ongoing education and training are key elements to equip surgical team members with the skills and knowledge they need to handle untimely and unexpected life-threatening scenarios in the perioperative setting. Regular emergency cardiopulmonary arrest skills education, including the use of checklists, and mock codes are ways to validate that team members understand their responsibilities and are competent to help if an arrest occurs in the OR. After a mock drill, a debriefing session can help team members discuss and critique their performances and improve their knowledge and mastery of skills. |
12,813 | Factors predisposing to small lacunar versus large non-lacunar cerebral infarcts: is left ventricular mass involved? | To find some specific determinants of lacunar strokes (LS), this study compared LS and non-LS patients using the size and location of cerebral lesions as discriminant between the two groups.</AbstractText>The main cardiovascular risk factors and some echocardiographic parameters were assessed in 225 ischemic stroke patients aged 75·1±11·4 (SD) years, including 101 patients with symptoms and lesions of lacunar type (deep hypodensities with diameter ≤ 1·5 cm) and 124 patients with non-lacunar lesions.</AbstractText>LS patients tended to be younger and had a higher prevalence of smokers than non-LS patients. In a subgroup undergoing echocardiogram, those with LS had a higher left ventricular mass index (LVMI) than non-LS patients (141·6±44·9 vs. 115·1±31·8 g/m(2), P = 0·005). The prevalence of hypertension, diabetes, and carotid stenoses > 50% was similar in the two groups. In multivariable analysis the ever-smoker status (OR = 1·9, P = 0·02), atrial fibrillation (inverse association, OR = 0·5, P = 0·03), LVMI ≥ 130 g/m(2) (OR = 6·6, P = 0·001), and age ≤ 72 years (OR = 5·9, P = 0·003) remained independently associated with LS.</AbstractText>The patients with lacunar cerebral lesions had a greater left ventricular mass than those with non-lacunar lesions, while blood pressure values did not differ. Lacunar lesions were also associated with smoking and a younger age.</AbstractText> |
12,814 | Noncoronary ST elevation and polymorphic ventricular tachycardia during left-sided accessory pathway ablation. | An early repolarization (ER) pattern on electrocardiogram (ECG) sometimes has the risk of polymorphic ventricular tachycardia (PVT) or ventricular fibrillation (VF). An abnormal ER pattern can develop in various experimental or clinical situations. We experienced 4 cases of abnormal ER pattern with or without PVT during the radiofrequency (RF) ablation of the left accessory pathway.</AbstractText>An electrophysiologic study and RF ablation were performed in 4 patients. Four patients had atrioventricular reentrant tachycardia. During RF ablation of the left accessory pathway, severe chest pain developed and was followed by abnormal J-point elevation. During the ongoing chest pain and J-point elevation, coronary angiograms showed normal findings. The chest pain and J-point elevation were followed by PVT or VF that was unresponsive to defibrillation. The PVT was spontaneously terminated and repeated. After 0.5 mg atropin was given, chest pain and ECG change disappeared.</AbstractText>The mechanisms of ER syndrome during RF ablation might be increased vagal tone due to chest pain or direct vagal stimulation.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,815 | Atrial fibrillation in cardiac resynchronization therapy with a defibrillator: a risk factor for mortality, appropriate and inappropriate shocks. | Knowledge about predictive factors for mortality and (in)appropriate shocks in cardiac resynchronization therapy with a defibrillator (CRT-D) should be available and updated to predict clinical outcome.</AbstractText>We retrospectively analyzed 543 consecutive patients assigned to CRT-D in 2 tertiary medical centers. The aim of this study was to assess risk factors for all-cause mortality, appropriate and inappropriate shocks.</AbstractText>Mean follow-up time was 3.2 (±1.8) years. A total of 110 (20%) patients died, 71 (13%) received ≥1 appropriate shocks, and 33 (6.1%) received ≥1 inappropriate shocks. No patients received a His bundle ablation and biventricular pacing percentage was not analyzed. Multivariable Cox regression analysis showed that a history of atrial fibrillation (AF) (HR 1.74 CI 1.06-2.86), higher creatinine (HR 1.12; CI 1.08-1.16), and a poorer left ventricular ejection fraction (LVEF) (HR 0.97; CI 0.94-1.01) independently predict all-cause mortality. In the entire cohort, history of AF and secondary prevention were independent predictors of appropriate shocks and variables associated with inappropriate shocks were history of AF and QRS ≥150 milliseconds. In primary prevention patients, history of AF also predicted appropriate shocks as did ischemic cardiomyopathy and poorer LVEF. History of AF, QRS ≥150 milliseconds, and lower creatinine were associated with inappropriate shocks in this subgroup. Appropriate shocks increased mortality risk, but inappropriate shocks did not.</AbstractText>In symptomatic CHF patients treated with CRT-D, history of AF is an independent risk factor not only for mortality, but also for appropriate and inappropriate shocks. Further efforts in AF management may optimize the care in CRT-D patients.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,816 | Melatonin attenuates hypertension-related proarrhythmic myocardial maladaptation of connexin-43 and propensity of the heart to lethal arrhythmias. | We hypothesized that the pineal hormone melatonin, which exhibits cardioprotective effects, might affect myocardial expression of cell-to-cell electrical coupling protein connexin-43 (Cx43) and protein kinase C (PKC) signaling, and hence, the propensity of the heart to lethal ventricular fibrillation (VF). Spontaneously hypertensive (SHR) and normotensive Wistar rats fed a standard rat chow received melatonin (40 μg/mL in drinking water during the night) for 5 weeks, and were compared with untreated rats. Melatonin significantly reduced blood pressure and normalized triglycerides in SHR, whereas it decreased body mass and adiposity in Wistar rats. Compared with healthy rats, the threshold to induce sustained VF was significantly lower in SHR (18.3 ± 2.6 compared with 29.2 ± 5 mA; p < 0.05) and increased in melatonin-treated SHR and Wistar rats to 33.0 ± 4 and 32.5 ± 4 mA. Melatonin attenuated abnormal myocardial Cx43 distribution in SHR, and upregulated Cx43 mRNA, total Cx43 protein, and its functional phosphorylated forms in SHR, and to a lesser extent, in Wistar rat hearts. Moreover, melatonin suppressed myocardial proapoptotic PKCδ expression and increased cardioprotective PKCε expression in both SHR and Wistar rats. Our findings indicate that melatonin protects against lethal arrhythmias at least in part via upregulation of myocardial Cx43 and modulation of PKC-related cardioprotective signaling. |
12,817 | Mineralocorticoid receptor and cardiac arrhythmia. | Mineralocorticoid receptor (MR) activation has been shown to play a deleterious role in the development of heart disease in studies using specific MR antagonists (spironolactone, eplerenone) in both experimental models and patients. Pharmacological MR blockade attenuates the transition to heart failure (HF) in models of systolic left ventricular dysfunction and myocardial infarction, as well as diastolic dysfunction, in rats and mice. In humans, MR antagonism is highly beneficial in patients with mild or advanced HF and postinfarct HF. The consequences of aldosterone and MR activation for cardiac arrhythmia and its prevention and/or correction by MR antagonists are often underestimated.  Activation of MR modulates cardiac electrical activity, causing atrial and ventricular arrhythmias. A pro-arrhythmogenic effect of aldosterone (possibly partly dependent on fibrosis) has been suggested by several studies. Cardiac MR activation has important consequences for the control of cellular calcium homeostasis, action potential lengthening, modulation of calcium transients and sarcoplasmic reticulum diastolic leaks, resulting in the promotion of rhythm disorders. Aldosterone and/or MR activation (in both cardiomyocytes and coronary vessels) result in vascular dysfunction and also contribute to pro-arrhythmogenic conditions.  Together, the pro-arrhythmic effects of aldosterone and/or MR may explain the highly beneficial effect of MR antagonism, namely a decrease in the incidence of sudden death, observed in the Randomized Aldactone Evaluation Study (RALES) and Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study (EPHESUS) studies. |
12,818 | Ibutilide and novel indexes of ventricular repolarization in persistent atrial fibrillation patients. | To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF).</AbstractText>We studied consecutive patients scheduled for elective electrical cardioversion. Intravenous ibutilide (1 + 1 mg) was administered before the electrical cardioversion while close electrocardiographic (ECG) monitoring was performed. ECG indexes such as corrected QT interval (QTc), the interval from the peak until the end of T wave (Tpe), and the Tpe/QT ratio were measured before ibutilide infusion and 10 min after the end of infusion.</AbstractText>The final study population consisted of 20 patients (mean age: 67.1 ± 9.9 years, 10 men). Six patients were cardioverted pharmacologically and did not proceed to electrical cardioversion. Two patients developed short non-sustained episodes of torsades de pointes ventricular tachycardia. All but one of the aforementioned ECG indexes increased significantly after ibutilide administration. In specific, the QTc interval increased from 442 ± 29 to 471 ± 37 ms (P = 0.037), the Tpe interval in precordial leads from 96 ms (range 80-108 ms) to 101 ms (range 91-119 ms) (P = 0.021), the Tpe interval in lead II from 79 ms (range 70-88 ms) to 100 ms (range 87-104 ms) (P < 0.001), the Tpe/QT ratio in precordial leads from 0.23 ms (range 0.18-0.26 ms) to 0.26 ms (range 0.23-0.28 ms) (P = 0.028), and the Tpe interval dispersion from 25 ms (range 23-30 ms) to 35 ms (range 27-39 ms) (P = 0.012). However, the Tpe/QT ratio in lead II did not change significantly.</AbstractText>Ibutilide increases the duration and dispersion of ventricular repolarization. The prognostic value of Tpe and Tpe/QT in the setting of drug-induced proarrhythmia needs further study.</AbstractText> |
12,819 | Hemodynamic directed cardiopulmonary resuscitation improves short-term survival from ventricular fibrillation cardiac arrest. | During cardiopulmonary resuscitation, adequate coronary perfusion pressure is essential for establishing return of spontaneous circulation. Current American Heart Association guidelines recommend standardized interval administration of epinephrine for patients in cardiac arrest. The objective of this study was to compare short-term survival using a hemodynamic directed resuscitation strategy versus chest compression depth-directed cardiopulmonary resuscitation in a porcine model of cardiac arrest.</AbstractText>Randomized interventional study.</AbstractText>Preclinical animal laboratory.</AbstractText>Twenty-four 3-month-old female swine.</AbstractText>After 7 minutes of ventricular fibrillation, pigs were randomized to receive one of three resuscitation strategies: 1) Hemodynamic directed care (coronary perfusion pressure-20): chest compressions with depth titrated to a target systolic blood pressure of 100 mm Hg and titration of vasopressors to maintain coronary perfusion pressure greater than 20 mm Hg; 2) Depth 33 mm: target chest compression depth of 33 mm with standard American Heart Association epinephrine dosing; or 3) Depth 51 mm: target chest compression depth of 51 mm with standard American Heart Association epinephrine dosing. All animals received manual cardiopulmonary resuscitation guided by audiovisual feedback for 10 minutes before first shock.</AbstractText>Forty-five-minute survival was higher in the coronary perfusion pressure-20 group (8 of 8) compared to depth 33 mm (1 of 8) or depth 51 mm (3 of 8) groups; p equals to 0.002. Coronary perfusion pressures were higher in the coronary perfusion pressure-20 group compared to depth 33 mm (p = 0.004) and depth 51 mm (p = 0.006) and in survivors compared to nonsurvivors (p < 0.01). Total epinephrine dosing and defibrillation attempts were not different.</AbstractText>Hemodynamic directed resuscitation targeting coronary perfusion pressures greater than 20 mm Hg during 10 minutes of cardiopulmonary resuscitation for ventricular fibrillation cardiac arrest improves short-term survival, when compared to resuscitation with depth of compressions guided to 33 mm or 51 mm and standard American Heart Association vasopressor dosing.</AbstractText> |
12,820 | Superior neurologic recovery after 15 minutes of normothermic cardiac arrest using an extracorporeal life support system for optimized blood pressure and flow. | Sudden cardiac arrest is one of the leading causes of death. Conventional CPR techniques after cardiac arrest provide circulation with reduced and varying blood flow and pressure. We hypothesize that using pressure- and flow-controlled reperfusion of the whole body improves neurological recovery and survival after 15 min of normothermic cardiac arrest.</AbstractText>Pigs were randomized in two experimental groups and exposed to 15 min of ventricular fibrillation (VF). After this period, the animals in the control group received conventional CPR with open chest compression (n=6), while circulation in the treatment group (n=6) was established with an extracorporeal life support system (ECLS) to control blood pressure and flow. Follow-up included the assessment of neurological recovery and magnetic resonance imaging (MRI) for up to 7 days.</AbstractText>Five of the six animals in the control group died, one animal was resuscitated successfully. In the treatment group, 1/6 could not be separated from ECLS. Five out of the six pigs survived and were transferred to the animal facility. One animal was unable to walk and had to be sacrificed 30 hours after ECLS. The remaining 4 animals of the treatment group and the surviving pig from the control group showed complete neurological recovery. Brain MRI revealed no pathological changes.</AbstractText>We were able to demonstrate a significant improvement in survival after 15 minutes of normothermic cardiac arrest. These results support our hypothesis that using an ECLS for pressure- and flow-controlled circulation after circulatory arrest is superior to conventional CPR.</AbstractText> |
12,821 | [Catheter ablation of ventricular tachycardia]. | Since the last decade important advances in diagnostics, understanding and the ablation techniques of ventricular tachycardia (VT) have been made. Both, patients with idiopathic VT and patients with structural heart disease and scar-related VT undergo VT ablation, that targets the underlying substrate responsible for VT development. Use of 3-dimensional electro-anatomic mapping systems enables identification of scar-related slow conduction sites, that are the critical players in scar-related VT. Successful mapping and ablation of mono- and polymorphic VT and ventricular fibrillation is achieved at specialized centers and is associated with reduced hospitalizations and mortality in patients with recurrent ICD shocks. This article describes the mechanisms of VTs, current mapping and ablation techniques and the results and complications of VT ablation at experienced VT ablation centers. |
12,822 | Nicotinamide adenine dinucleotide phosphate oxidase 4 mediates the differential responsiveness of atrial versus ventricular fibroblasts to transforming growth factor-β. | Atrial fibrosis, a common feature of atrial fibrillation, is thought to originate from the differential response of atrium versus ventricle to pathological insult. However, detailed mechanisms underlying the regional differences remain unclear. The aim of this study was to investigate the related factor(s) in mediating atrial vulnerability to fibrotic processes.</AbstractText>We first compared the response of cultured atrial versus ventricular fibroblasts with transforming growth factor-β (TGF-β), a key mediator of myocardial fibrosis. Atrial fibroblasts showed a stronger response to TGF-β1 in producing extracellular matrix protein (collagen and fibronectin) than ventricular fibroblasts. Furthermore, TGF-β1 activated its downstream signaling (Smads) and induced pronounced oxidative stress, including up-regulation of nicotinamide adenine dinucleotide phosphate oxidase in atrial fibroblasts, and to a lesser extent in ventricular fibroblasts. Nicotinamide adenine dinucleotide phosphate oxidase inhibitors and small-interfering RNA for Nox4 eliminated TGF-β-induced difference between atrial and ventricular fibroblasts, suggesting the crucial role of Nox4 in mediating the atrial-ventricular discrepancy. Small-interfering RNA for Smad3 also suppressed the differential responsiveness of atrial versus ventricular fibroblasts to TGF-β1, including Nox4 activation, implicating a crosstalk between nicotinamide adenine dinucleotide phosphate oxidases and Smad. In vivo, the increased TGF-β1 responsiveness and Nox4 expression were documented in the atria of transgenic mice with cardiac overexpression of TGF-β1.</AbstractText>Atrial fibroblasts show greater fibrotic and oxidative responses to TGF-β1 than ventricular fibroblasts. Nox4-derived reactive oxygen species production mediates the susceptibility of atrial fibroblasts to TGF-β1 via activating TGF-β1/Smad signaling cascade, which provides a novel insight into the pathogenesis of atrial fibrosis.</AbstractText> |
12,823 | Impact of stepwise ablation on the biatrial substrate in patients with persistent atrial fibrillation and heart failure. | Ablation of persistent atrial fibrillation can be challenging, often involving not only pulmonary vein isolation (PVI) but also additional linear lesions and ablation of complex fractionated electrograms (CFE). We examined the impact of stepwise ablation on a human model of advanced atrial substrate of persistent atrial fibrillation in heart failure.</AbstractText>In 30 patients with persistent atrial fibrillation and left ventricular ejection fraction ≤35%, high-density CFE maps were recorded biatrially at baseline, in the left atrium (LA) after PVI and linear lesions (roof and mitral isthmus), and biatrially after LA CFE ablation. Surface area of CFE (mean cycle length ≤120 ms) remote to PVI and linear lesions, defined as CFE area, was reduced after PVI (18.3±12.03 to 10.2±7.1 cm(2); P<0.001) and again after linear lesions (7.7±6.5 cm(2); P=0.006). Complete mitral isthmus block predicted greater CFE reduction (P=0.02). Right atrial CFE area was reduced by LA ablation, from 25.9±14.1 to 12.9±11.8 cm(2) (P<0.001). Estimated 1-year arrhythmia-free survival was 72% after a single procedure. Incomplete linear lesion block was an independent predictor of arrhythmia recurrence (hazard ratio, 4.69; 95% confidence interval, 1.05-21.06; P=0.04).</AbstractText>Remote LA CFE area was progressively reduced following PVI and linear lesions, and LA ablation reduced right atrial CFE area. Reduction of CFE area at sites remote from ablation would suggest either regression of the advanced atrial substrate or that these CFE were functional phenomena. Nevertheless, in an advanced atrial fibrillation substrate, linear lesions after PVI diminished the target area for CFE ablation, and complete lesions resulted in a favorable clinical outcome.</AbstractText> |
12,824 | Idiopathic dilated cardiomyopathy and chronic atrial fibrillation. | Atrial fibrillation (AF) is common in idiopathic dilated cardiomyopathy (IDC). We explored the clinical characteristics of IDC patients with chronic AF compared with those with sinus rhythm (SR).</AbstractText>A group of patients with IDC underwent extensive non-invasive and invasive evaluation during a hospitalization period. The patients were further divided into two groups with AF (n = 19) and SR (n = 68).</AbstractText>Left atrial diameter was greater (P<0·001), left ventricular end-diastolic diameter smaller (P<0·05), left ventricular end-diastolic and end-systolic volumes smaller (P<0·01 for all), mean pulmonary artery pressure and pulmonary capillary wedge pressure higher (P<0·05 for both), cardiac output and maximal oxygen consumption lower (P<0·01 and P<0·05, respectively), and the levels of N-terminal pro-brain natriuretic peptide and interleukin-6 higher (P<0·05 for both) in AF group compared with SR group. Left ventricular ejection fraction and left ventricular end-diastolic pressure were similar in both groups.</AbstractText>In spite of otherwise more unfavourable prognostic factor profile, left ventricular size was observed to be smaller in chronic AF compared with SR in well-characterized patients with IDC. The confirmation and possible explainers of this paradoxical phenomenon need further studies in larger patient cohorts.</AbstractText>© 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.</CopyrightInformation> |
12,825 | Ventricular fibrillation complicating endomyocardial biopsy of transplanted heart. | Life-threatening arrhythmia is an unusual complication of endomyocardial biopsy in transplanted heart. Herein we described a case of VF during endomyocardial biopsy. The possibility of VF during a biopsy necessitates immediate access to defibrillation during endomyocardial biopsy. |
12,826 | Catheter ablation of arrhythmias exclusively using electroanatomic mapping: a series of cases. | Catheter ablation is a treatment that can cure various cardiac arrhythmias. Fluoroscopy is used to locate and direct catheters to areas that cause arrhythmias. However, fluoroscopy has several risks. Electroanatomic mapping (EAM) facilitates three-dimensional imaging without X-rays, which reduces risks associated with fluoroscopy.</AbstractText>We describe a series of patient cases wherein cardiac arrhythmia ablation was exclusively performed using EAM.</AbstractText>Patients who presented with cardiac arrhythmias that were unresponsive to pharmacological therapy were prospectively selected between March 2011 and March 2012 for arrhythmia ablation exclusively through EAM. Patients with indications for a diagnostic electrophysiology study and ablation of atrial fibrillation, left atrial tachyarrhythmias as well as hemodynamically unstable ventricular arrhythmia were excluded. We documented the procedure time, success rate and complications as well as whether fluoroscopy was necessary during the procedure.</AbstractText>In total, 11 patients were enrolled in the study, including seven female patients (63%). The mean age of the patients was 50 years (SD ± 16.5). Indications for the investigated procedures included four cases (35%) of atrial flutter, three cases (27%) of pre-excitation syndrome, two cases (19%) of paroxysmal supraventricular tachycardia and two cases (19%) of ventricular extrasystoles. The mean procedure duration was 86.6 min (SD ± 26 min). Immediate success (at discharge) of the procedure was evident for nine patients (81%). There were no complications during the procedures.</AbstractText>This study demonstrates the feasibility of performing an arrhythmia ablation exclusively using EAM with satisfactory results.</AbstractText> |
12,827 | Optimal strength and number of shocks at upper limit of vulnerability testing required to predict high defibrillation threshold without inducing ventricular fibrillation. | The upper limit of vulnerability (ULV) closely correlates with the defibrillation threshold (DFT). The aim of this study was to establish the optimal protocol for using the ULV test to predict high DFT (>20 J) without inducing ventricular fibrillation (VF).</AbstractText>The 10-J and 15-J ULV test with 3 coupling intervals (-20, 0, and +20 ms to the peak of T-wave) and the DFT test were performed in 96 patients receiving implantable cardioverter defibrillator. ULV ≤ 10 J was confirmed in 47 (49%). ULV ≤ 15 J was confirmed in 70 (77%) of 91 patients (15-J ULV test could not be done in 5). The sensitivity and negative predictive value of both ULV >10 J and >15 J for predicting high DFT were 100%. The specificity and positive predictive value of ULV >15 J were higher than those for ULV >10 J (85% vs. 55%, 43% vs. 22%, respectively). The rate of VF inducibility for confirming ULV ≤ 15 J was lower than that for ULV ≤ 10 J (23% vs. 51%, P<0.0001). On analysis of single 15-J ULV test only at the peak of T-wave, VF was not induced in 79 of 91 patients, but 4 of these had high DFT.</AbstractText>The 15-J ULV test with 3 coupling intervals could correctly identify high-DFT patients and reduce the necessity for VF induction at defibrillator implantation. </AbstractText> |
12,828 | Single-shock defibrillation success in adult cardiac arrest: a systematic review. | Current resuscitation guidelines advise a single biphasic shock followed by chest compressions; however, it is unclear if this applies to all waveforms and energy levels. We conducted a systematic review of the literature to determine the comparative success rates for single-shock defibrillation across waveforms evaluated in out-of-hospital cardiac arrest patients.</AbstractText>EMBASE, MEDLINE, EBM Reviews, dissertation abstract databases, and clinicaltrials.gov were searched. Two investigators independently reviewed titles, abstracts and full texts in a hierarchical manner for study eligibility with a quadratic kappa score at each level. Two authors abstracted data independently and the quality of the articles was assessed using the five-point Jadad scale. Outcomes were termination of ventricular fibrillation (VF)/ventricular tachycardia (VT) at 5s post shock (TOF), return of organized rhythm (ROOR) and return of spontaneous circulation (ROSC).</AbstractText>A total of 3281 potentially relevant citations were identified and, of these, eight papers were selected with Kappa values of 0.53 for titles, 0.71 for abstracts, and 0.94 for articles. Quality scores varied from 0 to 4/5. Biphasic first-shock success for all three outcomes of interest was similar regardless of energy levels, and uniformly superior to monophasic first-shock success. Median time to first shock varied across trials based on level of randomization (first responders versus advanced life support tiered response) and may contribute to observed differences. Lack of variability across two waveforms precluded a meta-analytical approach.</AbstractText>This systematic review suggests that evaluated biphasic waveforms have similar first-shock success as measured by the three outcomes of interest and all are superior to monophasic shocks.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,829 | Performance measures for management of chronic heart failure patients with acute coronary syndrome in China: results from the Bridging the Gap on Coronary Heart Disease Secondary Prevention in China (BRIG) Project. | Chronic heart failure (CHF) is a severe clinical syndrome associated with high morbidity and mortality, and with high health care expenditures. No nationwide data are currently available regarding the quality of clinical management of CHF patients in China. The aim of this study was to assess the quality of care of CHF inpatients in China.</AbstractText>The American College of Cardiology/American Heart Association Clinical Performance Measures for Adults with Chronic Heart Failure (Inpatient Measurement Set) with slight modifications was used to measure the performance status in 612 CHF patients with acute coronary syndrome (ACS) from 65 hospitals across all regions of China.</AbstractText>The implementation rates of guideline recommended strategies for CHF management were low. Only 57.5% of the CHF patients received complete discharge instructions, 53.6% of the patients received evaluation of left ventricular systolic function, 62.8% received an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker at discharge, and 52.7% received a β-blocker at discharge, 56.3% of the smokers received smoking cessation counseling. The rate of warfarin utilization was only 9.7% in CHF patients with atrial fibrillation. Most patients (81.4%) did not receive all the first four treatments. There were marked differences in the quality of CHF management among patients with different characteristics.</AbstractText>Performance measures provide a standardized method of assessing quality of care, and can thus highlight problems in disease management in clinical practice. The quality of care for CHF patients with ACS in China needs to be improved.</AbstractText> |
12,830 | Genetic ACE I/D polymorphism and recurrence of atrial fibrillation after catheter ablation. | The angiotensin-converting enzyme (ACE) deletion allele, ACE D, is associated with increased cardiac ACE activity, cardiac fibrosis, and adverse outcomes in cardiovascular disease and has been linked with failure of antiatrial fibrillation (anti-AF) drug treatment. This study tested the hypothesis that the ACE gene insertion/deletion polymorphism associates with AF recurrence after catheter ablation.</AbstractText>In 238 consecutive patients (69% male; mean age, 58±11 years) undergoing catheter ablation of paroxysmal (59%) or persistent (41%) AF, the ACE insertion/deletion polymorphism was genotyped using polymerase chain reaction. After a blanking period of 3 months, AF recurrence (defined as any atrial arrhythmia lasting ≥30 s) was detected using serial 7-day Holter ECG recordings after 3, 6, and 12 months. AF recurrence was observed in 39% and was associated with persistent AF, longer history of AF, previous antiarrhythmic drug use, previous use of diuretics, increased left atrial diameter, increased left ventricular end-diastolic diameter, additional linear ablation lesions, and ACE DD polymorphism. In multivariable analysis, left atrial diameter (odds ratio, 1.111; 95% confidence interval, 1.040-1.187; P=0.002) and ACE DD genotype (odds ratio, 2.251; 95% confidence interval, 1.056-4.798; P=0.036) remained predictors for AF recurrence.</AbstractText>Left atrial enlargement and the ACE DD polymorphism are predictors for AF recurrence after catheter ablation. The association between the ACE DD polymorphism and AF recidivism supports the use of genetic data for predicting response to AF therapies and highlights the role of fibrosis in AF development.</AbstractText> |
12,831 | Defibrillation threshold testing does not predict clinical outcomes during long-term follow-up: a meta-analysis. | Defibrillation threshold (DFT) testing at the time of implantable cardioverter defibrillator (ICD) implantation is widely used in clinical practice, but reliable data supporting its routine use are lacking. We undertook a meta-analysis to evaluate the efficacy of DFT testing compared to no DFT testing at the time of ICD implantation.</AbstractText>We searched the MEDLINE and EMBASE databases for studies evaluating the effect of DFT testing on total mortality and ventricular arrhythmias during follow-up. Risk ratios (RR) with 95% confidence intervals (CI) were calculated using random effects modeling.</AbstractText>Eight studies involving 5,020 patients (3,068 undergoing DFT and 1,952 not undergoing DFT) were included. Of those, only one study was randomized. Reasons for not performing DFT included patient characteristics (four studies), center's standard practice (three studies), or randomization (one study). Median follow-up was 24 months. Overall, the quality of the included studies was rather poor. On the basis of the pooled estimate across the studies, DFT testing did not reduce total mortality or ventricular arrhythmias at follow-up (RR = 0.94, 95% CI 0.74-1.21; P = 0.65 and RR = 1.19, 95% CI 0.85-1.68; P = 0.30, respectively). No individual study had a major impact on the estimated RR or the statistical significance based on a sensitivity analysis.</AbstractText>Recognizing the limited quality of current studies in the area of DFT testing and outcomes, available data suggest that DFT testing at the time of ICD implantation does not appear to predict total mortality and ventricular arrhythmias during follow-up. Large randomized controlled trials, adequately powered to detect clinical outcomes, are warranted.</AbstractText>©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,832 | Does the combination of hyperkalemia and KATP activation determine excitation rate gradient and electrical failure in the globally ischemic fibrillating heart? | Ventricular fibrillation (VF) in the globally ischemic heart is characterized by a progressive electrical depression manifested as a decline in the VF excitation rate (VFR) and loss of excitability, which occur first in the subepicardium (Epi) and spread to the subendocardium (Endo). Early electrical failure is detrimental to successful defibrillation and resuscitation during cardiac arrest. Hyperkalemia and/or the activation of ATP-sensitive K(+) (KATP) channels have been implicated in electrical failure, but the role of these factors in ischemic VF is poorly understood. We determined the VFR-extracellular K(+) concentration ([K(+)]o) relationship in the Endo and Epi of the left ventricle during VF in globally ischemic hearts (Isch group) and normoxic hearts subjected to hyperkalemia (HighK group) or a combination of hyperkalemia and the KATP channel opener cromakalim (HighK-Crom group). In the Isch group, Endo and Epi values of [K(+)]o and VFR were compared in the early (0-6 min), middle (7-13 min), and late (14-20 min) phases of ischemic VF. A significant transmural gradient in VFR (Endo > Epi) was observed in all three phases, whereas a significant transmural gradient in [K(+)]o (Epi > Endo) occurred only in the late phase of ischemic VF. In the Isch group, the VFR decrease and inexcitability started to occur at much lower [K(+)]o than in the HighK group, especially in the Epi. Combining KATP activation with hyperkalemia only shifted the VFR-[K(+)]o curve upward (an effect opposite to real ischemia) without changing the [K(+)]o threshold for asystole. We conclude that hyperkalemia and/or KATP activation cannot adequately explain the heterogeneous electrical depression and electrical failure during ischemic VF. |
12,833 | [Subclinical hyperthyroidism]. | Subclinical hyperthyroidism is defined as abnormal low TSH level with thyroid hormones within their reference range. This laboratory condition may be symptomatic in a relevant number of patients leading to tachycardia, sweating, nervousness, anxiety and insomnia. The risk for cardiovascular disease is increased with more frequent atrial fibrillation and increased left ventricular mass including diastolic dysfunction. Cardiovascular mortality and overall mortality surmounts the average of the normal population. Longterm TSH suppression leads to decreased bone mineral density and an increased fracture rate in the hip and in the spine. After evaluation of underlying causes, therapy should be considered, especially if TSH levels are below 0.1 mIU/l. |
12,834 | Myocardial infarction and atrial fibrillation: importance of atrial ischemia. | Myocardial infarction (MI) is associated with the development of atrial fibrillation (AF). We aimed to characterize the atrial abnormalities because of MI and determine the role of ischemia to the AF substrate.</AbstractText>Forty-four sheep were studied. MI was induced by occlusion of the left circumflex artery (LCX) or left anterior descending artery (LAD). Excluding 11 with fatal arrhythmias, equal groups of animals (LCX; LAD; and sham-operated) underwent sequential electrophysiology study for 45 minutes to determine atrial effective refractory periods, conduction velocity, conduction heterogeneity index, and AF inducibility. Postmortem evaluation was performed with 2,3,5 triphenyl tetrazolium chloride staining. MI resulted in greater left ventricular dysfunction (P<0.05), LA pressure (P<0.0003), and reduction in atrial effective refractory periods (P<0.0001) compared with control. 2,3,5 triphenyl tetrazolium chloride staining demonstrated that the left circumflex artery, and not the LAD, group had atrial infarction. The left circumflex artery group demonstrated the following compared with the LAD or control groups: greater slowing in atrial conduction velocity (P<0.0001 and P<0.001); increased absolute range of conduction phase delay (P<0.001 and P<0.001); increased conduction heterogeneity index (P<0.0001 and P<0.001); greater AF vulnerability (P<0.05 for both); and longer AF duration (P<0.05 for both). LAD group had modest but significant slowing in conduction velocity (P<0.01) but no change in conduction heterogeneity index or AF duration compared with control.</AbstractText>Left ventricular infarction, which is known to result in atrial stretch, hemodynamic change, and neurohumoral activation, contributes partially to the atrial abnormalities in MI. Atrial ischemia/infarction results in greater atrial electrophysiological changes and propensity for AF forming the dominant substrate for AF in MI.</AbstractText> |
12,835 | The QT interval and risk of incident atrial fibrillation. | Abnormal atrial repolarization is important in the development of atrial fibrillation (AF), but no direct measurement is available in clinical medicine.</AbstractText>To determine whether the QT interval, a marker of ventricular repolarization, could be used to predict incident AF.</AbstractText>We examined a prolonged QT interval corrected by using the Framingham formula (QT(Fram)) as a predictor of incident AF in the Atherosclerosis Risk in Communities (ARIC) study. The Cardiovascular Health Study (CHS) and Health, Aging, and Body Composition (ABC) study were used for validation. Secondary predictors included QT duration as a continuous variable, a short QT interval, and QT intervals corrected by using other formulas.</AbstractText>Among 14,538 ARIC study participants, a prolonged QT(Fram) predicted a roughly 2-fold increased risk of AF (hazard ratio [HR] 2.05; 95% confidence interval [CI] 1.42-2.96; P < .001). No substantive attenuation was observed after adjustment for age, race, sex, study center, body mass index, hypertension, diabetes, coronary disease, and heart failure. The findings were validated in Cardiovascular Health Study and Health, Aging, and Body Composition study and were similar across various QT correction methods. Also in the ARIC study, each 10-ms increase in QT(Fram) was associated with an increased unadjusted (HR 1.14; 95% CI 1.10-1.17; P < .001) and adjusted (HR 1.11; 95% CI 1.07-1.14; P < .001) risk of AF. Findings regarding a short QT interval were inconsistent across cohorts.</AbstractText>A prolonged QT interval is associated with an increased risk of incident AF.</AbstractText>© 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,836 | The phenotype characteristics of type 13 long QT syndrome with mutation in KCNJ5 (Kir3.4-G387R). | Long QT syndrome type 13 (LQT13) is caused by loss-of-function mutation in the KCNJ5-encoded cardiac G-protein-coupled inward rectifier potassium channel subtype 4 protein. The electrocardiographic (ECG) features of LQT13 are not described yet.</AbstractText>To describe for the first time in detail the phenotype-genotype relationship of the ECG and clinical features in patients with LQT13.</AbstractText>The 12-lead ECGs, 24-hour Holter recordings, and clinical information from KCNJ5-G387R mutation carriers of a fourth-generation Han Chinese family with LQT13 and a group of healthy Chinese individuals were analyzed.</AbstractText>Compared with the analysis of the healthy group (n = 8), age- and sex-matched pair analysis revealed that the mutation carriers (n = 8) had ventricular repolarization abnormality results in the prolongation of corrected QT and QTpeak intervals (P < .01); greater combined measure of repolarization morphology (T-wave morphology combination score) based on asymmetry, flatness, and notch (P < .01); and reduced low frequency/high frequency ratio of heart rate variability (P < .01) as a reflection of cardiac autonomic imbalance. Mean heart rate, time domain parameters of heart rate variability, time interval from T-wave peak to T-wave end, and T-wave amplitude were similar.</AbstractText>This study demonstrates for the first time the ECG features of patients with LQT13. Our data suggest that QTpeak intervals and T-wave morphology combination score may be the better parameters than the corrected QT interval to predict the phenotype-genotype relationship in patients with LQT13.</AbstractText>© 2013 Heart Rhythm Society. All rights reserved.</CopyrightInformation> |
12,837 | Fever-induced Brugada pattern: how common is it and what does it mean? | Fever is known to unmask the Brugada pattern on the electrocardiogram (ECG) and trigger ventricular arrhythmias in patients with Brugada syndrome. Genetic studies in selected cases with fever-induced Brugada pattern have identified disease-causing mutations. Thus, "fever-induced Brugada" is a recognized clinical entity. However, its prevalence has not been systematically evaluated.</AbstractText>The purpose of this study was to assess the prevalence of Brugada pattern in consecutive patients with fever.</AbstractText>ECGs of patients with fever admitted to the emergency department were evaluated for the presence of Brugada pattern and compared with ECGs of consecutive nonfebrile patients.</AbstractText>ECGs of 402 patients with fever and 909 without were evaluated. Type I Brugada pattern was 20 times more common in the febrile group than in the afebrile group (2% vs. 0.1%, respectively, P = .0001). All patients with fever-induced type I Brugada pattern were asymptomatic and remained so during 30 months of follow-up.</AbstractText>Type I Brugada pattern is definitively more common among patients with fever, suggesting that asymptomatic Brugada syndrome is more prevalent than previously estimated.</AbstractText>© 2013 Heart Rhythm Society. All rights reserved.</CopyrightInformation> |
12,838 | Response of right ventricular size to treatment with cardiac resynchronization therapy and the risk of ventricular tachyarrhythmias in MADIT-CRT. | Cardiac resynchronization therapy (CRT) is increasingly recognized for its ability to reduce ventricular tachyarrhythmias, possibly associated with left ventricular reverse remodeling, but the role of the right ventricle (RV) in this process has not been examined.</AbstractText>The purpose of this study was to investigate the relationship between ventricular tachyarrhythmias and change in RV dimensions in patients receiving CRT with a defibrillator (CRT-D).</AbstractText>Multivariate Cox proportional hazards regression modeling was used to assess the risk for fast (≥180 bpm) ventricular tachycardia/ventricular fibrillation (VT/VF) or death by baseline and follow-up RV size (defined as right ventricular end-diastolic area [RVEDA]) among 1495 patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT).</AbstractText>Multivariate analysis showed that treatment with CRT-D was independently associated with a 27% (P = .003) reduction in the risk of VT/VF or death among patients with larger RVs (>first quartile RVEDA ≥13 mm(2)/m(2)) compared with implantable cardioverter-defibrillator (ICD)-only therapy, whereas in patients with smaller RVs there was no significant difference in the risk of VT/VF between the 2 treatment arms (hazard ratio = 1.00, P = .99). At 1-year follow-up, CRT-D patients displayed significantly greater reductions in RVEDA compared to ICD-only patients (P <.001), associated with a corresponding reduction in the risk of subsequent VT/VF or death (>first quartile reduction in RVEDA with CRT-D vs ICD-only: hazard ratio = 0.55, P <.001) independent of changes in left ventricular dimensions.</AbstractText>Our findings suggest that the RV may have an important role in determining the antiarrhythmic effect of CRT independent of the effect of the device on the left ventricle.</AbstractText>© 2013 Heart Rhythm Society. All rights reserved.</CopyrightInformation> |
12,839 | Exercise increases age-related penetrance and arrhythmic risk in arrhythmogenic right ventricular dysplasia/cardiomyopathy-associated desmosomal mutation carriers. | This study sought to determine how exercise influences penetrance of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) among patients with desmosomal mutations.</AbstractText>Although animal models and anecdotal evidence suggest that exercise is a risk factor for ARVD/C, there have been no systematic human studies.</AbstractText>Eighty-seven carriers (46 male; mean age, 44 ± 18 years) were interviewed about regular physical activity from 10 years of age. The relationship of exercise with sustained ventricular arrhythmia (ventricular tachycardia/ventricular fibrillation [VT/VF]), stage C heart failure (HF), and meeting diagnostic criteria for ARVD/C (2010 Revised Task Force Criteria [TFC]) was studied.</AbstractText>Symptoms developed in endurance athletes (N = 56) at a younger age (30.1 ± 13.0 years vs. 40.6 ± 21.1 years, p = 0.05); they were more likely to meet TFC at last follow-up (82% vs. 35%, p < 0.001) and have a lower lifetime survival free of VT/VF (p = 0.013) and HF (p = 0.004). Compared with those who did the least exercise per year (lowest quartile) before presentation, those in the second (odds ratio [OR]: 6.64, p = 0.013), third (OR: 16.7, p = 0.001), and top (OR: 25.3, p < 0.0001) quartiles were increasingly likely to meet TFC. Among 61 individuals who did not present with VT/VF, the 13 subjects experiencing a first VT/VF event over a mean follow-up of 8.4 ± 6.7 years were all endurance athletes (p = 0.002). Survival from a first VT/VF event was lowest among those who exercised most (top quartile) both before (p = 0.036) and after (p = 0.005) clinical presentation. Among individuals in the top quartile, a reduction in exercise decreased VT/VF risk (p = 0.04).</AbstractText>Endurance exercise and frequent exercise increase the risk of VT/VF, HF, and ARVD/C in desmosomal mutation carriers. These findings support exercise restriction for these patients.</AbstractText>Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,840 | The prognostic value of end tidal carbon dioxide during cardiac arrest: a systematic review. | Cardiac arrest is a common presentation to the emergency care system. The decision to terminate CPR is often challenging to heath care providers. An accurate, early predictor of the outcome of resuscitation is needed. The purpose of this systematic review is to evaluate the prognostic value of ETCO2 during cardiac arrest and to explore whether ETCO2 values could be utilised as a tool to predict the outcome of resuscitation.</AbstractText>Literature search was performed using Medline and EMBASE databases to identify studies that evaluated the relationship between ETCO2 during cardiac arrest and outcome. Studies were thoroughly evaluated and appraised. Summary of evidence and conclusions were drawn from this systematic literature review.</AbstractText>23 observational studies were included. The majority of studies showed that ETCO2 values during CPR were significantly higher in patients who later developed ROSC compared to patients who did not. Several studies suggested that initial ETCO2 value of more than 1.33 kPa is 100% sensitive for predicting survival making ETCO2 value below 1.33 kPa a strong predictor of mortality. These studies however had several limitations and the 100% sensitivity for predicting survival was not consistent among all studies.</AbstractText>ETCO2 values during CPR do correlate with the likelihood of ROSC and survival and therefore have prognostic value. Although certain ETCO2 cut-off values appears to be a strong predictor of mortality, the utility of ETCO2 cut-off values during CPR to accurately predict the outcome of resuscitation is not fully established. Therefore, ETCO2 values cannot be used as a mortality predictor in isolation.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,841 | Prognostic value of N-terminal pro-brain natriuretic Peptide in outpatients with hypertrophic cardiomyopathy. | In hypertrophic cardiomyopathy, the plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) correlate with functional capacity. However, their prognostic relevance remains unresolved. We followed up 183 stable outpatients with hypertrophic cardiomyopathy (age 50 ± 17 years, 64% men) for 3.9 ± 2.8 years after NT-proBNP measurement. The primary end point included cardiovascular death, heart transplantation, resuscitated cardiac arrest, and appropriate implantable cardioverter-defibrillator intervention. The secondary end point (SE) included heart failure-related death or hospitalization, progression to end-stage disease, and stroke. The median NT-proBNP level was 615 pg/ml (intertertile range 310 to 1,025). The incidence of the primary end point in the lower, middle, and upper tertiles was 0%, 1.3%, and 2.1% annually, respectively (overall p = 0.01). On multivariate analysis, the only independent predictors of the primary end point were NT-proBNP (hazard ratio for log-transformed values 5.8, 95% confidence interval 1.07 to 31.6; p = 0.04) and a restrictive left ventricular filling pattern (hazard ratio 5.19, 95% confidence interval 1.3 to 21.9; p = 0.02). The NT-proBNP cutoff value of 810 pg/ml had the best sensitivity for the primary end point (88%), but the specificity was low (61%). The incidence of the SE in the lower, middle, and upper NT-proBNP tertiles was 4.6%, 12.0%, and 11.2% annually, respectively (overall p = 0.001). An NT-proBNP level of <310 pg/ml was associated with a 75% reduction in the rate of SE compared with a level of ≥310 pg/ml (hazard ratio 0.25, 95% confidence interval 0.11 to 0.57; p = 0.001), independent of age, left ventricular outflow tract obstruction, or atrial fibrillation. In conclusion, in stable outpatients with hypertrophic cardiomyopathy, plasma NT-proBNP proved a powerful independent predictor of death and heart failure-related events. Although the positive predictive accuracy of an elevated NT-proBNP level was modest, low values reflected true clinical stability, suggesting the possibility of avoiding or postponing aggressive treatment options. |
12,842 | Predicting defibrillation success in sudden cardiac arrest patients. | Although the importance of quality cardiopulmonary resuscitation (CPR) and its link to survival is still emphasized, there has been recent debate about the balance between CPR and defibrillation, particularly for long response times. Defibrillation shocks for ventricular fibrillation (VF) of recently perfused hearts have high success for the return of spontaneous circulation (ROSC), but hearts with depleted adenosine triphosphate (ATP) stores have low recovery rates. Since quality CPR has been shown to both slow the degradation process and restore cardiac viability, a measurement of patient condition to optimize the timing of defibrillation shocks may improve outcomes compared to time-based protocols. Researchers have proposed numerous predictive features of VF and shockable ventricular tachycardia (VT) which can be computed from the electrocardiogram (ECG) signal to distinguish between the rhythms which convert to spontaneous circulation and those which do not. We looked at the shock-success prediction performance of thirteen of these features on a single evaluation database including the recordings from 116 out-of-hospital cardiac arrest patients which were collected for a separate study using defibrillators in ambulances and medical centers in 4 European regions and the US between March 2002 and September 2004. A total of 469 shocks preceded by VF or shockable VT rhythm episodes were identified in the recordings. Based on the experts' annotation for the post-shock rhythm, the shocks were categorized to result in either pulsatile (ROSC) or non-pulsatile (no-ROSC) rhythm. The features were calculated on a 4-second ECG segment prior to the shock delivery. These features examined were: Mean Amplitude, Average Peak-Peak Amplitude, Amplitude Range, Amplitude Spectrum Analysis (AMSA), Peak Frequency, Centroid Frequency, Spectral Flatness Measure (SFM), Energy, Max Power, Centroid Power, Power Spectrum Analysis (PSA), Mean Slope, and Median Slope. Statistical hypothesis tests (two-tailed t-test and Wilcoxon with 5% significance level) were applied to determine if the means and medians of these features were significantly different between the ROSC and no-ROSC groups. The ROC curve was computed for each feature, and Area Under the Curve (AUC) was calculated. Specificity (Sp) with Sensitivity (Se) held at 90% as well as Se with Sp held at 90% was also computed. All features showed statistically different mean and median values between the ROSC and no-ROSC groups with all p-values less than 0.0001. The AUC was >76% for all features. For Sp = 90%, the Se range was 33-45%; for Se = 90%, the Sp range was 49-63%. The features showed good shock-success prediction performance. We believe that a defibrillator employing a clinical decision tool based on these features has the potential to improve overall survival from cardiac arrest. |
12,843 | Relation between preoperative renal dysfunction and cardiovascular events (stroke, myocardial infarction, or heart failure or death) within three months of isolated coronary artery bypass grafting. | Renal dysfunction is related to long-term mortality and myocardial infarction after coronary artery bypass grafting (CABG). We aimed to investigate the association between preoperative renal dysfunction and early risk of stroke, myocardial infarction, or heart failure after CABG. From the Swedish Web-system for Enhancement and Development of Evidence-based care in Heart disease Evaluated According to Recommended Therapies registry, we included all 36,284 patients who underwent primary isolated CABG from 2000 to 2008 in Sweden. The Swedish National Inpatient Registry was used to obtain the primary end point, which was rehospitalization for stroke, myocardial infarction, or heart failure ≤90 days after CABG. Logistic regression models were used to estimate the risk for the primary outcome and the secondary outcome of death from any cause, while adjusting for confounders. During 90 days of follow-up, there were 2,462 cardiovascular events and 617 deaths. In total, 17% of patients developed acute kidney injury postoperatively. Odds ratios with 95% confidence intervals for cardiovascular events after adjustment for age, gender, atrial fibrillation, left ventricular ejection fraction, diabetes mellitus, peripheral vascular disease, and history of myocardial infarction, heart failure, or stroke was 1.24 (1.06 to 1.45) in patients with an estimated glomerular filtration rate of 15 to 45 ml/min/1.73 m(2) but became nonsignificant after acute kidney injury was introduced into the statistical model. The risk of death was significantly increased in patients with estimated glomerular filtration rate of 15 to 45 ml/min/1.73 m(2) (odds ratio 1.76, 95% confidence interval 1.38 to 2.25) even after adjustment for all confounders. Renal dysfunction was associated with all-cause mortality but not with cardiovascular events during the first 3 postoperative months after primary isolated CABG. |
12,844 | Prospective randomized study to assess the efficacy of site and rate of atrial pacing on long-term progression of atrial fibrillation in sick sinus syndrome: Septal Pacing for Atrial Fibrillation Suppression Evaluation (SAFE) Study. | Atrial-based pacing is associated with lower risk of atrial fibrillation (AF) in sick sinus syndrome compared with ventricular pacing; nevertheless, the impact of site and rate of atrial pacing on progression of AF remains unclear. We evaluated whether long-term atrial pacing at the right atrial (RA) appendage versus the low RA septum with (ON) or without (OFF) a continuous atrial overdrive pacing algorithm can prevent the development of persistent AF.</AbstractText>We randomized 385 patients with paroxysmal AF and sick sinus syndrome in whom a pacemaker was indicated to pacing at RA appendage ON (n=98), RA appendage OFF (n=99), RA septum ON (n=92), or RA septum OFF (n=96). The primary outcome was the occurrence of persistent AF (AF documented at least 7 days apart or need for cardioversion). Demographic data were homogeneous across both pacing site (RA appendage/RA septum) and atrial overdrive pacing (ON/OFF). After a mean follow-up of 3.1 years, persistent AF occurred in 99 patients (25.8%; annual rate of persistent AF, 8.3%). Alternative site pacing at the RA septum versus conventional RA appendage (hazard ratio=1.18; 95% confidence interval, 0.79-1.75; P=0.65) or continuous atrial overdrive pacing ON versus OFF (hazard ratio=1.17; 95% confidence interval, 0.79-1.74; P=0.69) did not prevent the development of persistent AF.</AbstractText>In patients with paroxysmal AF and sick sinus syndrome requiring pacemaker implantation, an alternative atrial pacing site at the RA septum or continuous atrial overdrive pacing did not prevent the development of persistent AF.</AbstractText>URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT00419640.</AbstractText> |
12,845 | Amplitude spectral area: predicting the success of electric shock delivered by defibrillators with different waveforms. | Prolonged ventricular fibrillation (VF) is associated with a low rate of return of spontaneous circulation (ROSC) following electric shock. Moreover, electric shock that does not reestablish spontaneous circulation causes myocardial dysfunction even if ROSC is subsequently achieved. Amplitude spectral area (AMSA), calculated by analysis of VF waveforms immediately before electric shock, is considered to predict the outcome of electric shock. This study aimed to evaluate the prognostic value of AMSA in relation to waveforms of defibrillators in prehospital settings.</AbstractText>The AMSA values of 81 patients with VF confirmed by ambulance crews were compared according to the type of defibrillators with different waveforms and between those with and without ROSC.</AbstractText>With a biphasic defibrillator, the mean AMSA was significantly different between the 14 patients who achieved ROSC (25.3 ± 9.5 mV-Hz) and the 43 subjects who did not achieve ROSC (15.4 ± 8.1 mV-Hz; p = 0.0006). No significant difference was seen in the corresponding values when a monophasic defibrillator was used, at 19.1 ± 2.4 mV-Hz for 3 ROSC patients and 16.1 ± 7.5mV-Hz for 21 non-ROSC patients.</AbstractText>AMSA may serve as a predictive measure for ROSC following electric shock delivered by a biphasic defibrillator.</AbstractText> |
12,846 | Characterization of acute heart failure hospitalizations in a Portuguese cardiology department. | We describe the clinical characteristics, management and outcomes of patients hospitalized with acute heart failure in a south-west European cardiology department. We sought to identify the determinants of length of stay and heart failure rehospitalization or death during a 12-month follow-up period.</AbstractText>This was a retrospective cohort study including all patients admitted during 2010 with a primary or secondary diagnosis of acute heart failure. Death and readmission were followed through 2011. Of the 924 patients admitted, 201 (21%) had acute heart failure, 107 (53%) of whom had new-onset acute heart failure. The main precipitating factors were acute coronary syndrome (63%) and arrhythmia (14%). The most frequent clinical presentations were heart failure after acute coronary syndrome (63%), chronic decompensated heart failure (47%) and acute pulmonary edema (21%). On admission 73% had left ventricular ejection fraction <50%. Median length of stay was 11 days and in-hospital mortality was 5.5%. The rehospitalization rate was 21% and 24% at six and 12 months, respectively. All-cause mortality was 16% at 12 months. The independent predictors of rehospitalization or death were heart failure hospitalization during the previous year (Hazard ratio - HR - 3.177), serum sodium <135mmol/l on admission (HR 1.995) and atrial fibrillation (HR 1.791). Reduced left ventricular ejection fraction was associated with a lower risk of rehospitalization or death (HR 0.518).</AbstractText>Our patients more often presented new-onset acute heart failure, due to an acute coronary syndrome, with reduced left ventricular ejection fraction. Several predictive factors of death or rehospitalization were identified that may help to select high-risk patients to be followed in a heart failure management program after discharge.</AbstractText>Copyright © 2012 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.</CopyrightInformation> |
12,847 | J wave is associated with increased risk of sudden cardiac arrest in patients with hypertrophic cardiomyopathy. | A retrospective, case-control study to investigate the J wave, a J-point elevation on resting 12-lead electrocardiograms, as a risk factor for sudden cardiac arrest (SCA) in patients diagnosed with hypertrophic cardiomyopathy (HCM).</AbstractText>Patients with HCM and age- and sex-matched healthy control subjects were recruited, and 12-lead electrocardiograms were performed. The prevalence and related characteristics of J waves were assessed. Patients were followed-up for a mean of 47.9 months.</AbstractText>Patients with HCM (n = 345) had significantly higher prevalence of J waves than healthy controls (n = 690; 11.6% and 7.1%, respectively). During follow-up, 14 patients with HCM experienced SCA (SCA subgroup). The prevalence of J waves was significantly higher in the SCA subgroup than in the non-SCA subgroup (42.9% and 10.3%, respectively). There were no significant differences between the SCA and non-SCA subgroups in J wave morphology.</AbstractText>The J wave may be a risk factor for SCA in patients with HCM.</AbstractText> |
12,848 | Temporal evolution and implications of ventricular arrhythmias associated with acute myocardial infarction. | It is important that clinicians have a clear understanding of the significance of ventricular arrhythmias (VAs) that occur in the context of acute myocardial infarction depending on the type of VA and timing in relation to the myocardial injury. This will greatly assist in evaluating prognostic implications and tailoring optimal strategies for management. This review presents an update on the current understanding of the pathogenesis, incidence, and clinical features of postinfarction VAs, and outcomes and potential therapeutic options. |
12,849 | The role of transcription factors in the formation of an arrhythmogenic substrate in congestive human heart failure. | Human congestive heart failure is accompanied by structural and electrical alterations leading to the development of an arrhythmogenic substrate. This substrate is associated with the "sudden cardiac death" due to ventricular tachycardia or ventricular fibrillation. Multiple studies link distinct transcription factors to the transcriptional regulation of genes related to the formation of an arrhythmogenic substrate. In addition to cardiac hypertrophy the up- or downregulation of ion channels, calcium-handling proteins, and proteins forming gap junctions play a pivotal role in the progression of heart failure. This review summarizes the transcriptional regulation of selected genes implicated in the formation of an arrhythmogenic substrate. In this context we provide an overview of relevant transcription factors, activating stimuli and pathways, the evidence of binding to respective elements in the promoter of target genes and the associated mRNA regulation in animal models. Finally, possible therapeutic consequences are discussed. |
12,850 | Use and associated risks of concomitant aspirin therapy with oral anticoagulation in patients with atrial fibrillation: insights from the Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) Registry. | The role of concomitant aspirin (ASA) therapy in patients with atrial fibrillation (AF) receiving oral anticoagulation (OAC) is unclear. We assessed concomitant ASA use and its association with clinical outcomes among AF patients treated with OAC.</AbstractText>The Outcomes Registry for Better Informed Treatment of Atrial Fibrillation (ORBIT-AF) registry enrolled 10 126 AF patients from 176 US practices from June 2010 through August 2011. The study population was limited to those on OAC (n=7347). Hierarchical multivariable logistic regression models were used to assess factors associated with concomitant ASA therapy. Primary outcomes were 6-month bleeding, hospitalization, ischemic events, and mortality. Overall, 35% of AF patients (n=2543) on OAC also received ASA (OAC+ASA). Patients receiving OAC+ASA were more likely to be male (66% versus 53%; P<0.0001) and had more comorbid illness than those on OAC alone. More than one third of patients (39%) receiving OAC+ASA did not have a history of atherosclerotic disease, yet 17% had elevated Anticoagulation and Risk Factors in Atrial Fibrillation (ATRIA) bleeding risk scores (≥5). Major bleeding (adjusted hazard ratio, 1.53; 95% confidence interval, 1.20-1.96) and bleeding hospitalizations (adjusted hazard ratio, 1.52; 95% confidence interval, 1.17-1.97) were significantly higher in those on OAC+ASA compared with those on OAC alone. Rates of ischemic events were low.</AbstractText>Patients with AF receiving OAC are often treated with concomitant ASA, even when they do not have cardiovascular disease. Use of OAC+ASA was associated with significantly increased risk for bleeding, emphasizing the need to carefully determine if and when the benefits of concomitant ASA outweigh the risks in AF patients already on OAC.</AbstractText>URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT01165710.</AbstractText> |
12,851 | [Recommendations for the treatment of heart failure : What's new?]. | Treatment escalation of chronic systolic heart failure depends on left ventricular function and symptoms of the patients. In symptomatic patients with severely reduced left ventricular function (ejection fraction ≤ 30 %), the following therapeutic approaches are recommended: (1) angiotensin-converting enzyme (ACE) inhibitors (angiotensin receptor blocker in case of ACE inhibitor intolerance); (2) β-blockers; (3) mineralocorticoid receptor antagonists; (4) diuretics in case of signs and symptoms of congestion; (5) digitalis, in particular in patients with atrial fibrillation; (6) ivabradine in patients with sinus rhythm and a heart rate ≥ 75/min; (7) an implantable cardioverter defibrillator (ICD); (8) in case of left bundle branch block or wide QRS complex, cardiac resynchronization therapy (CRT; in most cases in combination with an implantable cardioverter defibrillator); (9) intravenous administration of iron in case of iron deficiency; (10) exercise training should be strongly recommended in patients with stable heart failure. |
12,852 | Left atrial function by two-dimensional speckle-tracking echocardiography in patients with severe organic mitral regurgitation: association with guidelines-based surgical indication and postoperative (long-term) survival. | Left atrial (LA) mechanics in patients with severe mitral regurgitation (MR) remain largely unexplored. The aim of the present evaluation was to assess the effect of severe MR on LA function, its potential relation with conventional surgical indications, and long-term postoperative survival.</AbstractText>Two-dimensional speckle-tracking strain and volumetric indices of LA reservoir, conduit, and contractile function were assessed in 121 patients with severe MR and 70 controls. Patients were divided according to the presence (n = 46) or absence (n = 75) of one or more guidelines-based criteria for mitral surgery (symptoms, left ventricular ejection fraction ≤ 60%, left ventricular end-systolic diameter ≥ 40 mm, atrial fibrillation, or systolic pulmonary arterial pressure >50 mm Hg).</AbstractText>In patients with severe MR compared with controls, significant LA reservoir and contractile dysfunction was observed, which was more pronounced in patients with mitral surgery indication (P < .05 for all strain and volumetric indices). Of all indices of LA function, LA reservoir strain was an independent predictor (odds ratio, 0.88; 95% confidence interval, 0.82-0.94; P < .001) and had the highest accuracy to identify patients with indications for mitral surgery (area under the receiver operating characteristic curve, 0.8; 95% confidence interval, 0.72-0.87). A total of 117 patients underwent mitral valve surgery. Patients with LA reservoir strain ≤24% showed worse survival at a median of 6.4 years (interquartile range, 4.7-8.7 years) after mitral surgery (P = .02), regardless the symptomatic status before surgery. LA reservoir strain, on top of mitral surgery indications, provided incremental predictive value for postoperative survival.</AbstractText>Impaired LA reservoir strain in patients with severe organic MR relates to long-term survival after mitral valve surgery, independently of and incremental to current guidelines-based indications for mitral surgery.</AbstractText>Copyright © 2013 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
12,853 | Inappropriate use of antiarrhythmic drugs in paroxysmal and persistent atrial fibrillation in a large contemporary international survey: insights from RealiseAF. | International atrial fibrillation (AF) guidelines have defined optimal drugs for patients with various underlying diseases, but the extent to which real-life practice complies with these guidelines is unknown. This study aimed to evaluate the appropriate use of antiarrhythmic drugs (AADs) in patients with paroxysmal and persistent AF from the RealiseAF survey, according to the 2006 American College of Cardiology/American Heart Association/European Society of Cardiology AF guidelines.</AbstractText>RealiseAF was an international cross-sectional, observational survey of 10 523 eligible patients from 26 countries on 4 continents, with ≥1 AF episode documented by standard electrocardiogram or by Holter monitoring in the last 12 months. Participating physicians were randomly selected during 2009-10 from lists of office-based or hospital-based cardiologists and internists. Overall, 4947 patients with paroxysmal (n = 2606) or persistent AF (n = 2341) were included; mean (standard deviation) age was 64.7 (12.4) and 66.0 (11.8) years, respectively. Class Ic drugs were prescribed in 589 patients (11.9%); however, in 20.0% of these patients, the indication was not consistent with published guidelines. Similarly, for the 219 patients prescribed sotalol (4.4%), 16.0% received treatment for an indication that deviated from the published guidelines. Amiodarone was prescribed as first-line therapy in 1268 patients (25.6%), but 49.9% of these did not have heart failure or hypertension with significant left ventricular hypertrophy.</AbstractText>The use of AADs for persistent or paroxysmal AF in this large contemporary international survey showed some deviations from international guidelines. The highest discordance came with the use of amiodarone in first line. Clearly, there is a large discrepancy between published guidelines and current practice.</AbstractText> |
12,854 | Urgent catheter ablation for sustained ventricular tachyarrhythmias in patients with acute heart failure decompensation. | Ventricular tachycardia (VT) and ventricular fibrillation (VF) are not uncommon in patients hospitalized with acute heart failure (AHF). We sought to evaluate the efficacy of urgent radiofrequency catheter ablation (RFCA) for recurrent VT/VF during AHF decompensations.</AbstractText>The present study retrospectively analysed the data of 15 consecutive patients (69 ± 9 years, ischaemic heart disease in 10), who underwent urgent RFCA for frequent drug-refractory VT/VF episodes during an AHF decompensation with pulmonary congestion. The target arrhythmias were clinically documented monomorphic VTs in 10 patients, frequent premature ventricular contractions (PVCs) triggering VF in 4, and both in 1. The mean left ventricular ejection fraction was 26 ± 8%. The maximum number of arrhythmia episodes over 24 h was 9.1 ± 11.7. All RFCA sessions were completed without any major complications except for a temporary deterioration of pulmonary congestion in three patients (20%). Elimination and non-inducibility of the target arrhythmias were achieved in 13 patients (87%). Successful ablation site electrograms showed Purkinje potentials for all 5 PVCs triggering VF and 4 of 14 clinically documented monomorphic VTs (29%). Five patients (33%) underwent second sessions 10 ± 4 days after the first session for acute recurrences. Sustained VT/VF was completely suppressed during admission in 12 patients (80%), and the AHF ameliorated in 13 patients (93%). Twelve patients (80%) were discharged alive.</AbstractText>Urgent RFCA for drug-resistant sustained ventricular tachyarrhythmias during AHF decompensations would be an appropriate therapeutic option. Purkinje fibres can be ablation targets not only in those with PVCs triggering VF, but also in those with monomorphic VT.</AbstractText> |
12,855 | Two rings too tight: sequential emergency PCI for hemodynamic and arrhythmic complications of mitral and tricuspid valve repair. | New intra-operative mitral regurgitation is an unusual complication of tricuspid annuloplasty and maybe ischemic in etiology as a consequence of right coronary artery distortion. We report the case of a woman in whom this was treated by mitral valve annuloplasty with ensuing hemodynamic instability and ventricular arrhythmia secondary to a new left circumflex occlusion. Injury/distortion to either of the coronary arteries running in the atrio-ventricular groove is rare, and described only several times. To our knowledge, concurrent right coronary artery and circumflex artery injury/distortion has not been reported previously. |
12,856 | Genetic mutation in Korean patients of sudden cardiac arrest as a surrogating marker of idiopathic ventricular arrhythmia. | Mutation or common intronic variants in cardiac ion channel genes have been suggested to be associated with sudden cardiac death caused by idiopathic ventricular tachyarrhythmia. This study aimed to find mutations in cardiac ion channel genes of Korean sudden cardiac arrest patients with structurally normal heart and to verify association between common genetic variation in cardiac ion channel and sudden cardiac arrest by idiopathic ventricular tachyarrhythmia in Koreans. Study participants were Korean survivors of sudden cardiac arrest caused by idiopathic ventricular tachycardia or fibrillation. All coding exons of the SCN5A, KCNQ1, and KCNH2 genes were analyzed by Sanger sequencing. Fifteen survivors of sudden cardiac arrest were included. Three male patients had mutations in SCN5A gene and none in KCNQ1 and KCNH2 genes. Intronic variant (rs2283222) in KCNQ1 gene showed significant association with sudden cardiac arrest (OR 4.05). Four male sudden cardiac arrest survivors had intronic variant (rs11720524) in SCN5A gene. None of female survivors of sudden cardiac arrest had SCN5A gene mutations despite similar frequencies of intronic variants between males and females in 55 normal controls. Common intronic variant in KCNQ1 gene is associated with sudden cardiac arrest caused by idiopathic ventricular tachyarrhythmia in Koreans. |
12,857 | Impact of ageing on presentation and outcome of mitral regurgitation due to flail leaflet: a multicentre international study. | Define the impact of age at diagnosis on degenerative mitral regurgitation (MR) prognosis.</AbstractText>The Mitral regurgitation International DAtabase (MIDA) is a multicentre registry of MR due to flail leaflets including 862 patients (65 ± 12 years) diagnosed by echocardiography. The 498 older patients (≥65 years at diagnosis) were compared with the 364 younger (<65) with regard to presentation and the outcome was compared with that expected in the general population. Older vs. younger patients had MR of similar severity and ventricular overload but presented with more MR consequences and incurred higher mortality [risk ratio (rr) 95% confidence interval (95% CI) 4.7 (2.5-10.0), P < 0.001] independently of co-morbidity. Compared with expected survival [relative risk (95% confidence interval)], excess mortality, non-significant in younger patients [1.1 (0.6-2.0), P = 0.65], was prominent in older patients [1.4 (1.2-1.7), P < 0.001]. Compared with expected, excess heart failure (HF) occurred in younger [9.3 (6.5-13.3), P < 0.0001) and in older patients [6.7 (5.6-8.1), P < 0.0001]. Excess atrial fibrillation (AF) was even higher in younger [6.9 (4.5-10.6), P < 0.0001] than in older patients [3.5 (2.6-4.7), P < 0.0001; P < 0.001 for comparison between age groups]. Subsequent excess mortality [rr (95% CI)] was associated with occurrence of HF and/or AF in both age groups [13.5 (7.4-24.6), P < 0.001]. Mitral surgery was associated with reduced long-term mortality in older patients and lower rate of HF in both the age groups (all P < 0.01).</AbstractText>Both older and younger patients incurred excess risk of complications. Older patients suffered excess mortality, AF, and HF, whereas younger incurred excess morbidity linked to subsequent long-term excess mortality. The excess risks of uncorrected degenerative MR should be considered in deliberating surgical management, which significantly reduced mortality in older patients and HF in younger patients.</AbstractText> |
12,858 | Outcomes among athletes with arrhythmias and electrocardiographic abnormalities: implications for ECG interpretation. | Electrocardiographic (ECG) aberrations and arrhythmias occur frequently among athletes due to normal variants, subclinical cardiac disease or structural and electrical remodeling in response to training. It is unclear whether these changes are associated with adverse clinical outcomes over time among otherwise asymptomatic, healthy athletes. Consensus guidelines have been developed to guide the clinician regarding further management of these arrhythmias. The purpose of this review is to summarize prospective data regarding cardiovascular outcomes related to ECG changes among athletes and compare these findings with current guidelines. A review of the literature was conducted using the PubMed database (1966--present). Outcomes of interest included documented cardiac symptoms or events, such as episodes of cardiac or cerebral hypoperfusion, sudden death or prophylactic procedural interventions. Studies were included for analysis if they involved (1) athletes with documented, baseline arrhythmias and/or abnormal ECG variations; (2) a study design with longitudinal follow-up (designated as >1 month, to exclude short-term Holter studies); and (3) outcomes that include documented cardiac symptoms or events. A total of 33 studies met the above criteria, encompassing over 4,200 athletes, with follow-up ranging from 2 months to 14.6 years. There were few adverse outcomes among cases of sinus bradycardia >30 bpm, sinus pauses <3 s, first-degree atrioventricular (AV) block, second-degree type I AV block and incomplete right bundle branch block. Results among these studies are concordant with guidelines that recommend work-up in the setting of cardiac symptoms, history or physical examination indicative of cardiac disease, severe sinus bradycardia or AV block that does not resolve with exercise or hyperventilation. Outcomes among prospective studies also support guidelines that recommend further evaluation for repolarization abnormalities and supraventricular tachycardias, including atrial fibrillation, atrial flutter and Wolff-Parkinson-White syndrome. Ventricular arrhythmias in the setting of structural cardiac disease are associated with an increased risk of adverse events, including sudden cardiac death, and warrant special consideration with regards to sports eligibility. Findings in this review are limited by a lack of control groups, limited assessment of confounding factors (such as performance-enhancing drugs), and under-representation of women and certain ethnicities. Further prospective studies are needed to better characterize the long-term outcome of ECG abnormalities among athletes and provide evidence for ECG interpretation guidelines. |
12,859 | A prospective evaluation of haemodynamics, functional status, and quality of life after radiofrequency catheter ablation of long-standing persistent atrial fibrillation. | Clinical benefit from ablation for long-standing persistent atrial fibrillation has remained unknown. We hypothesized that successful ablation of long-standing persistent atrial fibrillation would improve haemodynamics, functional status, and quality of life.</AbstractText>A total of 160 patients (aged 59 ± 9 years, 23% females) undergoing ablation of long-standing (median of 28 months) persistent atrial were enrolled in this prospective study. Morphological and functional echocardiographic parameters, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), maximum oxygen consumption during exercise test (VO2 max), and quality of life were assessed at baseline and 1 year after the ablation.  At the 1-year follow-up visit, 81% patients were examined in sinus rhythm (after repeat ablation in 38% patients). Left atrial appendage outflow velocity increased from 44 ± 20 to 58 ± 23 cm/s, left ventricular ejection fraction from 54 ± 9 to 59 ± 5%, and VO2 max from 20.4 ± 6.4 to 23.7 ± 8.1 mL/kg/min; NT-proBNP decreased from median 897 (interquartile range 603-1424) to 230 (interquartile range 120-420) pg/mL (all P < 0.0001). These beneficial effects of ablation were predominantly associated with the presence of sinus rhythm. Quality of life (range 0-100) increased significantly (EQ-5D index: from 68.8 ± 12.5 to 75.4 ± 14.4; EQ-VAS score: from 62.8 ± 13.2 to 70.6 ± 13.8; both P < 0.0001).</AbstractText>Ablation of long-standing persistent atrial fibrillation was associated with significant recovery of haemodynamics and exercise capacity that projected onto the long-term improvement in quality of life.</AbstractText> |
12,860 | Atrial-based pacing has no benefit over ventricular pacing in preventing atrial arrhythmias in adults with congenital heart disease. | To determine whether atrial-based pacing prevents atrial arrhythmias in adults with congenital heart disease (CHD) compared with ventricular pacing.</AbstractText>All adult CHD patients from four participating centres with a permanent pacemaker were identified. Patients with permanent atrial arrhythmias at pacemaker implantation and patients who received a pacemaker for treatment of drug-refractory atrial arrhythmias were excluded. The final study population consisted of 211 patients (52% male, 36% complex CHD) who received a first pacemaker for sick sinus dysfunction (n = 82) or atrioventricular block (n = 129) at a median age of 24 years [interquartile range (IQR), 12-34]. A history of atrial arrhythmias at implantation was present in 49 patients (23%). Atrial-based pacing was the initial pacing mode in 139 patients (66%) while the others (34%) received ventricular pacing. During a median follow-up of 13 years (IQR, 7-21), 90 patients (43%) developed an atrial arrhythmia. Multivariate analysis demonstrated no significant effect of atrial-based pacing on subsequent atrial arrhythmias [hazard ratio (HR), 1.53; 95% confidence interval (CI), 0.91-2.56; P = 0.1]. Independent predictors of atrial arrhythmia were history of atrial arrhythmias (HR, 5.55; 95% CI, 3.47-8.89; P< 0.0001), older age (≥18 years) at pacemaker implantation (HR, 2.29; 95% CI, 1.29-4.04; P = 0.005), and complex CHD (HR, 1.57; 95% CI, 1.01-2.45; P = 0.04).</AbstractText>In contrast to the general population, atrial-based pacing was not associated with a lower incidence of atrial arrhythmia in adults with CHD.</AbstractText> |
12,861 | The effects of adenocaine (adenosine and lidocaine) on early post-resuscitation cardiac and neurological dysfunction in a porcine model of cardiac arrest. | Return of spontaneous circulation (ROSC) elicits ischaemia/reperfusion injury and myocardial dysfunction. The combination of adenosine and lidocaine (AL, adenocaine) has been shown to (1) inhibit neutrophil inflammatory activation and (2) improve left ventricular function after ischaemia. We hypothesized that resuscitation with adenocaine during early moments of cardiopulmonary resuscitation (CPR) attenuates leucocyte oxidant generation and myocardial dysfunction.</AbstractText>Pigs were randomized to: (1) sham (n=7), (2) cardiac arrest (CA; n=16), or 3) cardiac arrest+adenocaine (CA+AL; n=12). After 7 min of electrically induced ventricular fibrillation, start of CPR was followed by infusion of saline (CA) or adenocaine (CA+AL) for 6 min. Haemodynamics, cardiodynamics (pressure-volume loops) and leucocyte superoxide anion generation were assessed. Neurological function was evaluated after 24h by histology and neurological deficit score (0=normal; 500=brain dead).</AbstractText>Rate of ROSC was comparable between groups: CA group 11/16 and CA+AL group 7/12 p=0.57). Cardiac index transiently increased after ROSC in both groups. Left ventricular dysfunction demonstrated by a rightward shift of the intercept of end-systolic pressure-volume relations in CA was avoided in the CA+AL group. Leucocyte superoxide anion generation 2h after ROSC was significantly attenuated in the CA+AL group compared to the CA group. Neurological deficit scores [CA: median: 17.5(IQR:0-75) and CA+AL: 35(IQR:15-150)] and histopathological damage were comparable in both groups (p=0.37).</AbstractText>Infusion of adenocaine during early resuscitation from CA significantly improved early post-resuscitation cardiac function and attenuated leucocyte superoxide anion generation, without a change in post-ROSC neurological function. (IACUC protocol number 023-2009).</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,862 | A new method to estimate the amplitude spectrum analysis of ventricular fibrillation during cardiopulmonary resuscitation. | Accurate ventricular fibrillation (VF) waveform analysis usually requires rescuers to discontinue cardiopulmonary resuscitation (CPR). However, prolonged "hands-off" time has a deleterious impact on the outcome. We developed a new filter technique that could clean the CPR artifacts and help preserve the shockability index of VF METHODS: We analyzed corrupted ECGs, which were constructed by randomly adding different scaled CPR artifacts to the VF waveforms. A newly developed algorithm was used to identify the CPR fluctuations. The algorithm contained two steps. First, decomposing the raw data by empirical mode decomposition (EMD) into several intrinsic mode fluctuations (IMFs) and combining the dominant IMFs to reconstruct a new signal. Second, calculating each CPR cycle frequency from the new signal and fitting the new signal to the original corrupted ECG by least square mean (LSM) method to derive the CPR artifacts. The estimated VF waveform was derived by subtraction of the CPR artifacts from the corrupted ECG. We then performed amplitude spectrum analysis (AMSA) for original VF, corrupted ECG and estimated VF.</AbstractText>A total of 150 OHCA subjects with initial VF rhythm were included for analysis. Ten CPR artifacts signals were used to construct corrupted ECG. Even though the correlations of AMSA between the corrupted ECG vs. the original VF and the estimated VF vs. the original VF are all high (all p<0.001), the values of AMSA were obviously biased in corrupted ECG with wide limits of agreement in Bland-Altman mean-difference plot. ROC analysis of the AMSA in the prediction of defibrillation success showed that the new algorithm could preserve the cut-off AMSA value for CPR artifacts with power ratio to VF from 0 to 6 dB.</AbstractText>The new algorithm could efficiently filter the CPR-related artifacts of the VF ECG and preserve the shockability index of the original VF waveform.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
12,863 | Renal denervation suppresses ventricular arrhythmias during acute ventricular ischemia in pigs. | Increased sympathetic activation during acute ventricular ischemia is involved in the occurrence of life-threatening arrhythmias.</AbstractText>To test the effect of sympathetic inhibition by renal denervation (RDN) on ventricular ischemia/reperfusion arrhythmias.</AbstractText>Anesthetized pigs, randomized to RDN or SHAM treatment, were subjected to 20 minutes of left anterior descending coronary artery (LAD) occlusion followed by reperfusion. Infarct size, hemodynamics, premature ventricular contractions, and spontaneous ventricular tachyarrhythmias were analyzed. Monophasic action potentials were recorded with an epicardial probe at the ischemic area.</AbstractText>Ventricular ischemia resulted in an acute reduction of blood pressure (-29%) and peak left ventricular pressure rise (-40%), which were not significantly affected by RDN. However, elevation of left ventricular end-diastolic pressure (LVEDP) during LAD ligation was attenuated by RDN (ΔLVEDP: +1.8 ± 0.6 mm Hg vs +9.7 ± 1 mm Hg in the SHAM group; P = .046). Infarct size was not affected by RDN compared to SHAM. RDN significantly reduced spontaneous ventricular extrabeats (160 ± 15/10 min in the RDN group vs 422 ± 36/10 min in the SHAM group; P = .021) without affecting coupling intervals. In 5 of 6 SHAM-treated animals, ventricular fibrillation (VF) occurred during LAD occlusion. By contrast, only 1 of 7 RDN-treated animals experienced VF (P = .029). Beta-receptor blockade by atenolol showed comparable effects. Neither VF nor transient shortening of monophasic action potential duration during reperfusion was inhibited by RDN.</AbstractText>RDN reduced the occurrence of ventricular arrhythmias/fibrillation and attenuated the rise in LVEDP during left ventricular ischemia without affecting infarct size, changes in ventricular contractility, blood pressure, and reperfusion arrhythmias. Therefore, RDN may protect from ventricular arrhythmias during ischemic events.</AbstractText>© 2013 Heart Rhythm Society. All rights reserved.</CopyrightInformation> |
12,864 | Significance of non-type 1 anterior early repolarization in patients with inferolateral early repolarization syndrome. | The aim of this study was to investigate the significance of non-type 1 anterior early repolarization (NT1-AER) combined with inferolateral early repolarization syndrome (ERS).</AbstractText>Inferolateral ERS might be a heterogeneous entity, although it excludes type 1 Brugada syndrome (BS).</AbstractText>Of 84 patients with spontaneous ventricular fibrillation, 31 ERS patients were divided into 2 groups. The ERS(A)-group consisted of inferolateral ER and NT1-AER--that is, notching or slurring with J-wave ≥ 1 mm at the end of QRS to early ST segment in any of V1 to V3 leads, in which the ST-T segment did not change to a coved pattern in the standard and high costal (second and third) electrocardiographic recordings even after drug provocation tests (n = 12). The other, ERS(B)-group, showed only inferolateral ER (n = 19). Clinical characteristics and outcomes were compared between the ERS groups, 40 patients with type-1 BS (BS-group), and 13 patients with idiopathic ventricular fibrillation lacking J-wave (IVF-group).</AbstractText>Ventricular fibrillation occurred during sleep or near sleep in 10 of 12 patients in ERS(A)-group and in 22 of 40 patients in BS-group but in 2 of 19 patients in ERS(B)-group and in 1 of 13 patients in IVF-group (ERS[A] vs. ERS[B], p < 0.0001). Ventricular fibrillation recurrence was significantly higher in ERS(A)-group (58%), particularly in patients with J waves in the high lateral lead, and BS-group (55%), compared with ERS(B)-group (11%) and IVF-group (15%) (ERS[A] vs. ERS[B], p = 0.012).</AbstractText>Inferolateral ERS comprises heterogeneous ER subtypes with and without NT1-AER. Coexistence of NT1-AER was a key predictor of poor outcome in patients with ERS.</AbstractText>Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,865 | Transesophageal echocardiographic screening before atrial flutter ablation: is it necessary for patient safety? | Transesophageal echocardiography (TEE) is commonly used before atrial flutter (AFl) ablation to detect atrial thrombus (AT) and thereby identify a heightened risk for systemic embolism both in patients with their initial episodes of AFl and in those with prior episodes whose anticoagulation has been inadequate. This treatment strategy has been extrapolated from guidelines for atrial fibrillation. In fact, limited data exist regarding the prevalence or clinical associations of AT and spontaneous echocardiographic contrast (SEC) in patients with AFl. Both AT and SEC are believed to represent risk factors for systemic embolization. This study was designed to provide further insight into the prevalence of these and their associated clinical findings.</AbstractText>The results of transesophageal echocardiographic examinations in 347 consecutive patients with AFl in whom radiofrequency ablation procedures were planned were reviewed. In each case, specific care was taken to identify AT and SEC. The presence of either AT or more than mild SEC was considered to reflect a thrombogenic milieu (TM). Clinical and echocardiographic data were analyzed to determine the frequency and relevant clinical associations of these two markers of increased thromboembolic risk. In addition to determining the prevalence of AT and TM, the study sought to identify predictors of their presence short of TEE that might allow that procedure to be avoided.</AbstractText>AT were found in 19 of the 347 patients (5.4%). TM was present in 39 patients (11.2%). SEC was associated with reduced left atrial appendage emptying velocity (P < .001). History of myocardial infarction (P = .02) was associated with AT. Reduced left ventricular ejection fraction (P = .01), reduced left atrial appendage emptying velocity (P < .001), diabetes mellitus (P = .02), congestive heart failure (P = .04), and chronic renal insufficiency (P = .05) were associated with a TM.</AbstractText>Allowing for multiple comparisons, the significant markers of the risk for systemic embolization could be obtained only from TEE. Although there are several interesting clinical and echocardiographic associations with AT and a TM, none were strong enough to obviate the need for TEE.</AbstractText>Published by Mosby, Inc.</CopyrightInformation> |
12,866 | Focus on right ventricular outflow tract septal pacing. | Experimental and clinical studies have shown that right ventricular apical pacing may result in long-term deleterious effects on account of its negative impact on left ventricular remodeling through desynchronization. This risk appears more pronounced in patients with even moderate left ventricular dysfunction and generally occurs after at least 1 year of pacing. As right ventricular apical pacing may be associated with the development of organic mitral insufficiency, other sites that allow for more physiological stimulation, such as right ventricular outflow tract septal pacing, have been developed, with good feasibility and reproducibility. However, the prospective randomized studies and meta-analyses to date have only demonstrated a modest effect on ejection fraction in the medium term, without any significant effect on quality of life and morbimortality. However, the absence of a favorable effect for right ventricular outflow tract septal pacing compared with right ventricular apical pacing in terms of clinical manifestations and patient prognosis appears to be more associated with the designs of these studies, which were not homogeneous with regard to methodology used, judgment criteria, follow-up and, especially, statistical power. Two randomized prospective multicentre studies are currently ongoing in order to evaluate the favorable effect of infundibular septal pacing, when considering the indirect negative effects of right ventricular apical pacing as reported in the literature. |
12,867 | Effect of continuous compression and 30:2 cardiopulmonary resuscitation on cerebral microcirculation in a porcine model of cardiac arrest. | The effect of rescue breathing on neurologic prognosis after cardiopulmonary resuscitation (CPR) is controversial. Therefore, we investigated the cerebral microcirculatory and oxygen metabolism during continuous compression (CC) and 30:2 CPR (VC) in a porcine model of cardiac arrest to determine which is better for neurologic prognosis after CPR.</AbstractText>After 4 min of ventricular fibrillation, 20 pigs were randomised into two groups (n=10/group) receiving CC-CPR or VC-CPR. Cerebral oxygen metabolism and blood flow were measured continuously using laser Doppler flowmetry. Haemodynamic data were recorded at baseline and 5 min, 30 min, 2 h and 4 h after restoration of spontaneous circulation (ROSC).</AbstractText>Compared with the VC group, the mean cortical cerebral blood flow was significantly higher at 5 min ROSC in the CC group (P<0.05), but the difference disappeared after that time point. Brain percutaneous oxygen partial pressures were higher, and brain percutaneous carbon dioxide partial pressures were lower, in the VC group from 30 min to 4 h after ROSC; significant differences were found between the two groups (P<0.05). However, no significant difference of the cerebral oxygen extraction fraction existed between the two groups.</AbstractText>Inconsistency of systemic circulation and cerebral microcirculation with regard to blood perfusion and oxygen metabolism is common after CPR. No significant differences in cortical blood flow and oxygen metabolism were found between the CC-CPR and VC-CPR groups after ROSC.</AbstractText> |
12,868 | Myocardial fibrosis detected by cardiac CT predicts ventricular fibrillation/ventricular tachycardia events in patients with hypertrophic cardiomyopathy. | Myocardial fibrosis (MF) occurs in up to 80% of subjects with asymptomatic or mildly symptomatic hypertrophic cardiomyopathy (HCM) and can constitute an arrhythmogenic substrate for re-entrant, life-threatening ventricular arrhythmias in predisposed persons.</AbstractText>The aim was to investigate whether MF detected by delayed enhancement cardiac CT is predictive of ventricular tachycardia (VT) and fibrillation (VF) that require appropriate therapy by an implantable cardioverter defibrillator (ICD) in patients with HCM.</AbstractText>Twenty-six patients with HCM with previously (for at least 1 year) implanted ICD underwent MF evaluation by cardiac CT. MF was quantified by myocardial delayed enhanced cardiac CT. Data on ICD firing were recorded every 3 months after ICD implantation. Risk factors for sudden cardiac death in patients with HCM were evaluated in all patients.</AbstractText>MF was present in 25 of 26 patients (96%) with mean fibrosis mass of 20.5 ± 15.8 g. Patients with appropriate ICD shocks for VF/VT had significantly greater MF mass than patients without (29.10 ± 19.13 g vs 13.57 ± 8.31 g; P = .01). For a MF mass of at least 18 g, sensitivity and specificity for appropriate ICD firing were 73% (95% CI, 49%-88%) and 71% (95% CI, 56%-81%), respectively. Kaplan-Meier curves indicated a significantly greater VF/VT event rate in patients with MF mass ≥18 g than in patients with MF <18 g (P = .02). In the Cox regression analysis, the amount of MF was independently associated with VF/VT in ICD-stored electrograms.</AbstractText>The mass of MF detected by cardiac CT in patients with HCM at high risk of sudden death was associated with appropriate ICD firings.</AbstractText>Copyright © 2013 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
12,869 | Benefits of standardizing the treatment of arrhythmias in the sheep (Ovis aries) model of chronic heart failure after myocardial infarction. | Large animal models of heart failure are essential in preclinical device testing. In sheep, catheter-based coil embolization of the left anterior descending and diagonal artery provides a minimally invasive and reproducible model of myocardial infarction (MI). Although widely used, this model has historically been plagued with a 30% mortality rate, both in the literature and in our own experience. Our study endeavored to decrease the mortality rate by targeting the most common cause of death, intractable arrhythmias, during creation of the ovine MI model. To this end, we evaluated 2 methods of managing perioperative antiarrhythmic therapy and cardiopulmonary resuscitation during model creation. The first group of sheep was managed at the discretion of the individual operator, whereas the second group was treated according to a standardized protocol that included mandatory pretreatment with amiodarone. Sheep experiencing life-threatening arrhythmias, most commonly ventricular fibrillation, were either resuscitated according to operator-driven instructions or the standardized protocol. By comparing these 2 treatment groups, we have shown that using a standardized protocol is advantageous in reducing mortality associated with the ovine MI model. Since implementing the standardized protocol, our laboratory has lowered the expected mortality rate to 10% during catheter-based induction of ovine MI and has greatly reduced the number of animals required for study needs. In addition, the standardized protocol has proven beneficial in training new staff members. By implementing this standardized method of model management, the outcomes of model creation have been optimized. |
12,870 | Mechanisms of drug-induced proarrhythmia in clinical practice. | Drug-induced proarrhythmia represents a great challenge for those involved in the development of novel pharmaceuticals and in the regulatory bodies for drug approval as well as for the prescribing clinicians. Our understanding of the mechanisms that underlie drug-induced proarrhythmia has grown dramatically over the last two decades. A growing number of cardiac and non-cardiac agents have been shown to alter cardiac repolarization predisposing to fatal cardiac arrhythmias such as ventricular tachycardia or ventricular fibrillation and sudden cardiac death. These agents may induce the phenotype of long QT syndrome and less commonly of short QT syndrome and Brugada syndrome (BS). Although, genetic susceptibility underlie drug-induced proarrhythmia in certain cases, current data are limited regarding this topic. The present review surveys the current published literature on the mechanisms and the offending medical agents that predispose to drug-induced long QT syndrome, short QT syndrome and BS. Drug-induced proarrhythmia should be considered as a predictor of sudden cardiac death and should prompt critical re-evaluation of the risks and benefits of the suspicious medication. Survivors of drug-induced proarrhythmia and family members require careful examination and possibly genetic testing for the presence of a channelopathy. Treating physicians are advised to follow the lists of agents implicated in drug-induced proarrhythmia in order to minimize the risk of arrhythmia and sudden cardiac death. |
12,871 | The transverse-axial tubular system of cardiomyocytes. | A characteristic histological feature of striated muscle cells is the presence of deep invaginations of the plasma membrane (sarcolemma), most commonly referred to as T-tubules or the transverse-axial tubular system (TATS). TATS mediates the rapid spread of the electrical signal (action potential) to the cell core triggering Ca(2+) release from the sarcoplasmic reticulum, ultimately inducing myofilament contraction (excitation-contraction coupling). T-tubules, first described in vertebrate skeletal muscle cells, have also been recognized for a long time in mammalian cardiac ventricular myocytes, with a structure and a function that in recent years have been shown to be far more complex and pivotal for cardiac function than initially thought. Renewed interest in T-tubule function stems from the loss and disorganization of T-tubules found in a number of pathological conditions including human heart failure (HF) and dilated and hypertrophic cardiomyopathies, as well as in animal models of HF, chronic ischemia and atrial fibrillation. Disease-related remodeling of the TATS leads to asynchronous and inhomogeneous Ca(2+)-release, due to the presence of orphan ryanodine receptors that have lost their coupling with the dihydropyridine receptors and are either not activated or activated with a delay. Here, we review the physiology of the TATS, focusing first on the relationship between function and structure, and then describing T-tubular remodeling and its reversal in disease settings and following effective therapeutic approaches. |
12,872 | Neurological recovery after out-of-hospital cardiac arrest: hospital admission predictors and one-year survival in an urban cardiac network experience. | The aim of the study was to detect early predictors of neurological recovery and evaluate one year survival related to neurological status at discharge in patients (pts) admitted after out of hospital cardiac arrest (OHCA).</AbstractText>Sixty-three consecutive pts with OHCA from any cardiac cause, admitted to our cardiac intensive care unit, were classified according to survival and cerebral performance category (CPC) scale from 1 to 4 at hospital discharge. Pre-hospital and emergency room (ER) variables were analyzed to identify early predictors of neurological recovery as defined CPC=1-2.</AbstractText>Overall in-hospital survival was 60%. Sixty-eight and 32% of survivors were classified as CPC 1-2 and CPC 3-4 respectively. During one year follow-up 96% of patients classified as CPC 1-2 survived and 100% of CPC 3-4 died. Emergency crew witnessing, performance of cardio pulmonary resuscitation (CPR) by witnesses, the call for chest pain, no history of heart disease and a Glasgow coma scale (GCS) of ≥9 on arrival to the ER, were more frequent in patients classified as CPC 1-2 and times from "OHCA to return of spontaneous circulation (ROSC)", from "emergency medical system (EMS) arrival to ROSC" and "first DC shock to ROSC" were also significantly shorter in these patients. The time of first DC shock to ROSC in pts who presented with rhythm in ventricular fibrillation and the time from OHCA to ROSC in pts with witnessed OHCA were an independent predictors of neurological recovery.</AbstractText>Forty-one percent of pts admitted to our tertiary centre after OHCA were discharged with CPC 1-2 and at one year follow-up 96% of these were alive, while all pts classified as CPC 3-4 died. Easily documented information such as the time from OHCA to ROSC and the time of first shock to ROSC are early independent predictors of neurological recovery.</AbstractText> |
12,873 | Complete atrioventricular block does not reduce long-term mortality in patients with permanent atrial fibrillation treated with cardiac resynchronization therapy. | A maximum percentage of ventricular pacing is mandatory to obtain a good response to CRT. Atrioventricular junction (AVJ) ablation has been recommended to attain this objective in patients with AF.</AbstractText>(i) to determine whether the presence of complete AVJ block (induced or spontaneous) improves survival in patients with permanent AF treated with CRT and (ii) to analyse the predictors of mortality in AF patients treated with CRT.</AbstractText>From a series of 608 patients treated with CRT in our centre from 2000 to 2011, a cohort of 155 patients with permanent AF was analysed. Patients in AF were divided into two groups, AF + AVJ block [76 (49%)] and AF non-AVJ block [79 (51%)]. Mean follow-up was 30 months (interquartile range 13-51 months). During the follow-up, 62 patients died. Overall and cardiovascular mortality were similar between both groups: hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.51-1.39, P = 0.51 and HR 0.94, 95% CI 0.52-1.68, P = 0.82. Multivariate analysis identified three independent predictors of mortality: basal NYHA functional class IV (HR 2.25, 95% CI 1.12-4.22, P = 0.03), glomerular filtration rate (HR 0.98, 95% CI 0.96-0.99, P = 0.03), and LVEF (HR 0.94, 95% CI 0.89-0.99, P = 0.02).</AbstractText>AVJ block did not improve survival for patients in AF treated with CRT. Basal NYHA functional class IV, poor renal function, and LVEF were the independent predictors of mortality.</AbstractText> |
12,874 | Fragmented QRS complex predicts the arrhythmic events in patients with arrhythmogenic right ventricular cardiomyopathy/dysplasia. | Fragmented QRS (frQRS) complex, with various morphology, has been recently described as a diagnostic criterion of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D). However, there are little data regarding the prognostic role of frQRS in these patients. Therefore, we aimed to investigate the association of frQRS with arrhythmic events in patients with ARVC/D.</AbstractText>Seventy-eight patients (51 men, 65.4%; mean age: 31.25 ± 11.5 years) with the diagnosis of ARVC/D according to 2010 modified Task Force Criteria were analyzed retrospectively. Baseline ECG evaluation revealed frQRS complex in 46 patients (59%). Eleven patients with complete/incomplete right bundle branch block were excluded from the study. The phenomenon of frQRS was defined as deflections at the beginning of the QRS complex, on top of the R-wave, or in the nadir of the S-wave similar to the definition in CAD in either one right precordial lead or in more than one lead including all standard ECG leads.</AbstractText>During 38 ± 14 months follow-up period, 3 patients (3.8%) died suddenly, 36 patients (46.1%) experienced arrhythmic events (32 ventricular tachycardias [VTs] and 4 ventricular fibrillation [VF], 30 in the ICD group). The frQRS was significantly associated with arrhythmic events (P < 0.001). Also, the number of ECG leads with frQRS complex was higher in patients with arrhythmic events (5.08 ± 2.5 vs 1.14 ± 1.7, P < 0.001, respectively).</AbstractText>The frQRS complex on standard 12-lead ECG predicts fatal and nonfatal arrhythmic events in patients with ARVC/D. Therefore, large scale and prospective studies are needed to confirm those findings.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,875 | Spatiotemporal evolution and prediction of [Ca(2+) ]i and APD alternans in isolated rabbit hearts. | Action potential duration (APD) alternans can be accompanied by alternans in intracellular calcium transients ([Ca(2+) ]i ), leading to electromechanical alternans. Electromechanical alternans is considered a substrate for ventricular fibrillation. Although some techniques have been developed to predict APD alternans, the onset of [Ca(2+) ]i alternans has never been predicted.</AbstractText>Simultaneous mapping of voltage and calcium was performed in 8 Langendorff-perfused rabbit hearts. APD, [Ca(2+) ]i amplitude (CaA) and duration (CaD) alternans were induced using a perturbed downsweep protocol. Local onset of alternans (B(onset) ) was defined as the cycle length (BCL) at which at least 10% of the RV exhibited alternans. We observed that the local onset of CaA alternans always occurred first, followed by APD and then CaD alternans. We constructed APD, CaD, and CaA restitution portraits for 2 regions of the heart defined at B(onset) : the 1:1alt region, which developed alternans, and the 1:1 region, which did not. Our results also show that the slopes S12 Max and SDyn were higher in 1:1alt region (SDyn  = 0.99 ± 0.04 vs 0.73 ± 0.06; S12 Max  = 0.95 ± 0.13 vs 0.65 ± 0.1, P < 0.05) prior to onset of CaD alternans, while S12 and S12 Max were significantly higher in the 1:1alt region (S12  = 0.59 ± 0.19 vs 0.19 ± 0.02; S12 Max  = 1.09 ± 0.1 vs 0.61 ± 0.08, P < 0.05) prior to onset of CaA alternans.</AbstractText>We successfully applied the restitution portrait technique to the prediction of [Ca(2+) ]i (both CaA and CaD) alternans. The slopes of the APD/CaD/CaA restitution portrait are definitive indicators of APD, CaD, and CaA alternans.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
12,876 | Cardiac sarcoidosis. | Cardiac sarcoidosis is a rare entity and may be difficult to diagnose prior to cardiac surgery. We review the imaging and diagnostic studies necessary to make the diagnosis and discuss therapeutic algorithms to manage this disease. |
12,877 | Predictors of survival from perioperative cardiopulmonary arrests: a retrospective analysis of 2,524 events from the Get With The Guidelines-Resuscitation registry. | Perioperative cardiopulmonary arrests are uncommon and little is known about rates and predictors of in-hospital survival.</AbstractText>Using the Get With The Guidelines®-Resuscitation national in-hospital resuscitation registry, we identified all patients aged 18 yr or older who experienced an index, pulseless cardiac arrest in the operating room or within 24 h postoperatively. The primary outcome was survival to hospital discharge, and the secondary outcome was neurologically intact recovery among survivors. Multivariable logistic regression models using generalized estimating equation models were used to identify independent predictors of survival and neurologically intact survival.</AbstractText>A total of 2,524 perioperative cardiopulmonary arrests were identified from 234 hospitals. The overall rate of survival to discharge was 31.7% (799/2,524), including 41.8% (254/608) for ventricular tachycardia and ventricular fibrillation, 30.5% (296/972) for asystole, and 26.4% (249/944) for pulseless electrical activity. Ventricular fibrillation and pulseless ventricular tachycardia were independently associated with improved survival. Asystolic arrests occurring in the operating room and postanesthesia care unit were associated with improved survival when compared to other perioperative locations. Among patients with neurological status assessment at discharge, the rate of neurologically intact survival was 64.0% (473/739). Prearrest neurological status at admission, patient age, inadequate natural airway, prearrest ventilatory support, duration of event, and event location were significant predictors of neurological status at discharge.</AbstractText>Among patients with a perioperative cardiac arrest, one in three survived to hospital discharge, and good neurological outcome was noted in two of three survivors.</AbstractText> |
12,878 | Ventricular ectopy and QTc-interval prolongation associated with dronedarone therapy. | Amiodarone is an effective treatment for atrial and ventricular arrhythmias, but its use is limited by a toxic adverse-effect profile. Although dronedarone has been touted as an antiarrhythmic agent devoid of both solid organ toxicity and proarrhythmic properties, its potential for prolonging ventricular repolarization may augment triggered ectopy. We describe a 66-year-old man who began dronedarone 400 mg twice/day for new-onset paroxysmal atrial fibrillation; he had no left ventricular dysfunction or clinical heart failure. Three months after starting the drug, he complained of malaise, fatigue, and rare palpitations. Twenty four-hour Holter monitoring revealed increased premature ventricular complexes, and the rate-corrected QT (QTc) interval was prolonged (range 525-760 msec). Dronedarone was discontinued and the patient's symptoms gradually resolved over the next 3 weeks. Holter monitoring revealed a marked reduction in ventricular ectopy burden, and the QTc interval decreased to his baseline values. Even in the absence of documented symptomatic torsade de pointes, this case suggests that caution should be exercised when prescribing dronedarone and that serial QTc interval monitoring may be appropriate. In addition, clinicians should have a low threshold to perform Holter monitoring if symptoms develop during dronedarone therapy. |
12,879 | Outcome prediction in heart failure with atrial fibrillation: relative role of left ventricular ejection fraction and neurohormonal measures. | Since atrial fibrillation (AF) impacts the measurement and interpretation of left ventricular ejection fraction (LVEF), we hypothesized that the outcome in heart failure (HF) with AF and LVEF ≤ 35% would be more strongly associated with neurohormonal measures than LVEF.</AbstractText>Cardiac adverse events [CAE; HF progression (HFP), life-threatening arrhythmia (ARR), and cardiac death (CD)] and all-cause mortality (ACM) were recorded prospectively in 954 patients with HF and LVEF ≤ 35%: 852 in sinus rhythm (SR) and 102 in AF. Cox proportional hazard models found that the univariate hazard ratios (HR) for LVEF and the first CAE (primary outcome), HFP, ARR, CD, and ACM were significant in SR (0.933, P < .001, 0.933, P < .001, 0.929, P < .001, 0.916, P < .001, 0.945, P = .001, respectively), but not in AF (1.002, P = .95, 1.060, P = .24, 0.922, P = .15, 0.885, P = .09, 0.932, P = .25). HRs for CAEs and ACM and one or more neurohormonal measures (iodine 123 m-iodobenzylguanidine cardiac parameters, B-type natriuretic peptide, and plasma norepinephrine) were significant in SR and AF. The multivariate models for the first CAE and HFP included neurohormonal measures and LVEF in SR and neurohormonal measures in AF.</AbstractText>In HF with LVEF ≤ 35% with AF, neurohormonal measures, but not LVEF, were related to outcomes.</AbstractText> |
12,880 | Lower preoperative fluctuation of heart rate variability is an independent risk factor for postoperative atrial fibrillation in patients undergoing major pulmonary resection. | The following study presents a special independent atrial fibrillation (AF) risk factor-preoperative fluctuation of heart rate variability (HRV), as well as other perioperative AF risk factors in patients qualified for pneumonectomy and undergoing pneumonectomy or lobectomy for lung cancer.</AbstractText>The prospective study was performed in patients who had undergone anatomical resection for non-small-cell lung cancer. A total of 117 patients (92 men and 25 women) qualified for statistical research. In order to determine the risk factors, all patients were divided into two groups: Group A-98 patients without AF and Group B-19 patients with AF during the perioperative time. A number of different risk factors of AF have been analysed and further divided into preoperative, operative and postoperative.</AbstractText>Postoperative AF occurred in 19 patients (16%), all of them were male. The patients with higher short-term HRV parameters (SD1, RMSSD), slower mean heart rate and those with a lower fluctuation of HRV-related parameters (HRV Afternoon, Night, Day (A/N/D)) before the operation, were more prone to AF. Postoperative risk of AF was higher in patients with a higher number of ventricular ectopic beats before the operation, a higher number of supraventricular and ventricular ectopic beats and a higher maximal heart rate after the operation. Statistical analysis revealed that male gender and the extent of pulmonary resection, particularly left pneumonectomy, constituted significant risk factors. AF was more often observed in patients who had ASA physical status score of III, in comparison with ASAI and ASAII patients.</AbstractText>Along with other concomitant AF risk factors presented in this work, the evaluation of the fluctuation tendencies of HRV parameters should be taken into consideration before any major lung resection. The balance disturbance between the sympathetic and parasympathetic nervous systems is responsible for AF.</AbstractText> |
12,881 | Impact of left atrial volume on outcomes of pulmonary vein isolation in patients with non-paroxysmal (persistent) and paroxysmal atrial fibrillation. | Using a novel graded outcomes scale, the investigators evaluated whether left atrial (LA) volume measured by cardiac computed tomographic angiography is a predictor of pulmonary vein isolation success in patients with nonparoxysmal atrial fibrillation (AF) and paroxysmal AF (PAF). Data from 45 patients who underwent electrocardiographically gated computed tomographic angiography before pulmonary vein isolation for AF were used. LA volume was measured in the ventricular systolic and diastolic phases, defined as 40% and 75% of the interval between consecutive R waves. Outcomes were graded at 0 to 3, 3 to 6, 6 to 12, and 12 to 24 months after pulmonary vein isolation and scored on a 5-point scale: 1 = no AF recurrence off antiarrhythmic drug, 2 = no AF recurrence on antiarrhythmic drug, 3 = rare AF (<1 episode in 3 months), 4 = asymptomatic recurrent AF, and 5 = no reductions in AF frequency or severity. LA volumes were significantly larger in the nonparoxysmal AF group compared with the PAF group in systole (159.2 vs 128.2 ml, p <0.001) and diastole (137.1 vs 104.0 ml, p <0.001). In patients with PAF, larger LA volume was correlated with worse clinical outcomes in the first 12 months, but the results did not reach statistical significance (systole r = 0.25 to 0.41, diastole r = 0.20 to 0.34). In conclusion, these results show a significant difference in LA volume in patients with nonparoxysmal AF and PAF in systole and diastole. Additionally, there was a correlation between LA volume and clinical outcomes in patients with PAF, although this did not reach statistical significance. |
12,882 | CHADS2 and CHA2DS2-VASc scores to predict morbidity and mortality in heart failure patients candidates to cardiac resynchronization therapy. | CHADS2 and CHA2DS2-VASc scores are pivotal in assessing the risk of stroke in atrial fibrillation patients, and were recently proved to predict hospitalizations and mortality in specific clinical settings. Aim of this study was to evaluate whether these scores could predict clinical outcomes [first hospitalization for heart failure (HF) and a combined event of HF hospitalization and death for any cause] in patients candidates to cardiac resynchronization therapy and implantable defibrillator (CRT-D).</AbstractText>In a retrospective multicentre Italian study, we enrolled 559 consecutive HF patients candidates to CRT-D, and we grouped them in three pre-specified risk classes: low (CHADS2/CHA2DS2-VASc 1-2), moderate (CHADS2/CHA2DS2-VASc 3-4), and high (CHADS2 5-6/CHA2DS2-VASc 5-8). All patients underwent regular follow-up at implanting centres every 6 months; data collection was extended till the 72th month of follow-up. At a median FU of 30 months, 143 patients (25.4%) were hospitalized for HF and 110 (19.5%) died. Event-free survival analysis showed a significant difference according to baseline CHADS2 and CHA2DS2-VASc scores (Log-Rank for HF P < 0.001 for CHADS2 and CHA2DS2-VASc; Log-Rank for combined end-point P = 0.001 for CHADS2, P < 0.001 for CHA2DS2-VASc). At multivariate analysis, independent predictors of endpoints were: previous atrial fibrillation (AF) or AF at implant, NYHA class, QRS duration and the CHA2DS2-VASc score (for HF hospitalization P = 0.013; for the combined event, P = 0.007), while the CHADS2 score was not independently associated with either the end-points.</AbstractText>In CRT-D patients, pre-implant CHA2DS2-VASc score is an independent predictor of major clinical events at 30-month follow-up.</AbstractText> |
12,883 | Electrophysiology procedures: weighing the factors affecting choice of anesthesia. | Invasive electrophysiologic procedures have evolved and increased in frequency significantly over the past 2 decades. The complexity and nature of the various procedures offered have also changed, and complex ablations for atrial fibrillation and ventricular tachycardia have become commonplace. These procedures often require the services of an anesthesiologist. An understanding of the specific nature and challenges of these procedures may be helpful in planning the optimal anesthetic and patient management. A paired review of these issues has been written from the standpoint of a practicing anesthesiologist. This review is written from the viewpoint of a cardiac electrophysiologist and will focus on the intra-procedural management of patients undergoing both cardiac implantable device implantation as well as catheter-based ablations, with a specific focus on the catheter ablation of atrial fibrillation. Ultimately, the proper management of these patients will facilitate successful procedural outcomes while maintaining a high degree of patient safety. |
12,884 | Effects of atrial natriuretic peptide after prolonged hypothermic storage of the isolated rat heart. | Primary graft failure (PGF) caused by ischemia-reperfusion injury (IRI) is the strongest determinant of perioperative mortality after heart transplantation. Atrial natriuretic peptide (ANP) has been found to reduce the IRI of cardiomyocytes and may be beneficial in alleviating PGF after heart transplantation, although there is a lack of evidence to support this issue. The purpose of this study was to investigate the cardioprotective effects of ANP after prolonged hypothermic storage. For this purpose, an isolated working-heart rat model was used. After the preparation, the hearts were arrested with and stored in an extracellular-based cardioplegic solution at 3-4°C for 6 h and followed by 25 min of reperfusion. The hearts were divided into four groups (n = 7 in each group) according to the timing of ANP administration: Group 1 (in perfusate before storage), Group 2 (in cardioplegia), Group 3 (in reperfusate), and control (no administration of ANP). Left ventricular functional recovery and the incidence of ventricular fibrillation (VF) were compared. ANP administration at the time of reperfusion improved the percent recovery of left ventricular developed pressure (control, 45.5 ± 10.2; Group 1, 47.4 ± 8.8; Group 2, 45.3 ± 12 vs. Group 3, 76.3 ± 7; P < 0.05) and maximum first derivative of the left ventricular pressure (control, 47.9 ± 8.7; Group 1, 46.7 ± 8.8; Group 2, 49.6 ± 10.8 vs. Group 3, 76.6 ± 7.5; P < 0.05). The incidence of VF after reperfusion did not differ significantly among these four groups (71.4, 85.7, 57.1, and 85.7% in Groups 1, 2, 3, and control, respectively). This result suggests that the administration of ANP at the time of reperfusion may have the potential to decrease the incidence of PGF after heart transplantation. |
12,885 | Reduced Ventricular Arrhythmogeneity and Increased Electrical Complexity in Normal Exercised Rats. | The mechanisms whereby aerobic training reduces the occurrence of sudden cardiac death in humans are not clear. We test the hypothesis that exercise-induced increased resistance to ventricular tachycardia and fibrillation (VT/VF) involve an intrinsic remodeling in healthy hearts.</AbstractText>Thirty rats were divided into a sedentary (CTRL, n = 16) and two exercise groups: short- (4 weeks, ST, n = 7) and long-term (8 weeks, LT, n = 7) trained groups. Following the exercise program hearts were isolated and studied in a Langendorff perfusion system. An S1-S2 pacing protocol was applied at the right ventricle to determine inducibility of VT/VF. Fast Fourier transforms were applied on ECG time-series. In-vivo measurements showed training-induced increase in aerobic capacity, heart-to-body weight ratio and a 50% low-to-high frequency ratio reduction in the heart rate variability (p<0.05). In isolated hearts the probability for VF decreased from 26.1±14.4 in CTRL to 13.9±14.1 and 6.7±8.5% in the ST and LT, respectively (p<0.05). Duration of VF also decreased from 19.0±5.7 in CTRL to 8.8±7.1 and 6.0±5.8 sec in ST and LT respectively (p<0.05). Moreover, the pacing current required for VF induction increased following exercise (2.9±1.7 vs. 5.4±2.1 and 8.5±0.9 mA, respectively; p<0.05). Frequency analysis of ECG revealed an exercise-induced VF transition from a narrow single peak spectrum at 17 Hz in CTRL to a broader range of peaks ranging between 8.8 and 22.5 Hz in the LT group (p<0.05).</AbstractText>Exercise in rats leads to reduced VF propensity associated with an intrinsic cardiac remodeling related to a broader spectral range and faster frequency components in the ECG.</AbstractText> |
12,886 | Determinants of myocardial conduction velocity: implications for arrhythmogenesis. | Slowed myocardial conduction velocity (θ) is associated with an increased risk of re-entrant excitation, predisposing to cardiac arrhythmia. θ is determined by the ion channel and physical properties of cardiac myocytes and by their interconnections. Thus, θ is closely related to the maximum rate of action potential (AP) depolarization [(dV/dt)max], as determined by the fast Na(+) current (I Na); the axial resistance (r a) to local circuit current flow between cells; their membrane capacitances (c m); and to the geometrical relationship between successive myocytes within cardiac tissue. These determinants are altered by a wide range of pathophysiological conditions. Firstly, I Na is reduced by the impaired Na(+) channel function that arises clinically during heart failure, ischemia, tachycardia, and following treatment with class I antiarrhythmic drugs. Such reductions also arise as a consequence of mutations in SCN5A such as those occurring in Lenègre disease, Brugada syndrome (BrS), sick sinus syndrome, and atrial fibrillation (AF). Secondly, r a, may be increased due to gap junction decoupling following ischemia, ventricular hypertrophy, and heart failure, or as a result of mutations in CJA5 found in idiopathic AF and atrial standstill. Finally, either r a or c m could potentially be altered by fibrotic change through the resultant decoupling of myocyte-myocyte connections and coupling of myocytes with fibroblasts. Such changes are observed in myocardial infarction and cardiomyopathy or following mutations in MHC403 and SCN5A resulting in hypertrophic cardiomyopathy (HCM) or Lenègre disease, respectively. This review defines and quantifies the determinants of θ and summarizes experimental evidence that links changes in these determinants with reduced myocardial θ and arrhythmogenesis. It thereby identifies the diverse pathophysiological conditions in which abnormal θ may contribute to arrhythmia. |
12,887 | Electrical shock survival after prolonged cardiopulmonary resuscitation. | Electrical shock is typically an untoward exposure of human body to any source of electricity that causes a sufficient current to pass through the skin, muscles or hair causing undesirable effects ranging from simple burns to death. Ventricular fibrillation is believed to be the most common cause of death following electrical shock. The case under discussion is of a young man who survived following electrical shock after prolonged cardiopulmonary resuscitation (CPR), multiple defibrillations and artificial ventilation due to poor respiratory effort. Early start of chest compressions played a vital role in successful CPR. |
12,888 | Left atrial responses to acute right ventricular apical pacing in patients with sick sinus syndrome. | Chronic right ventricular apical (RVA) pacing can lead to an increased risk of heart failure and atrial fibrillation, but the acute effects of RVA pacing on left atrial (LA) function are not well known. Twenty-four patients with sick sinus syndrome and intact intrinsic atrioventricular conduction were included. All patients received dual-chamber pacemaker implants with the atrial lead in the right atrial appendage and the ventricular lead in the right ventricular (RV) apex. Transthoracic standard and strain echocardiography (measured by tissue Doppler imaging and speckle tracking image) were performed to identify functional changes in the left ventricle (LV) and LA before and after 1 hour of RVA pacing. The LA volume index did not change after pacing; however, the ratio of peak early diastolic mitral flow velocity (E) to peak early diastolic mitral annular velocity (Ea) was significantly increased and peak systolic LA strain (Sm), mean peak systolic LA strain rate (SmSR), peak early diastolic LA strain rate (EmSR), and peak late diastolic LA strain rate (AmSR) were significantly reduced after RV pacing. LV dyssynchrony, induced by RV pacing, had a significant correlation with E/Ea, Sm, and SmSR after pacing. E/Ea also had a negative correlation with Sm and SmSR after pacing. Multivariate regression analysis identified LV dyssynchrony and E/Ea as important factors that affect Sm, SmSR, EmSR, and AmSR after acute RVA pacing. Acute RVA pacing results in LA functional change and LV dyssynchrony and higher LV filling pressures reflected by E/Ea are important causes of LA dysfunction after acute RVA pacing. |
12,889 | Recurrent ventricular fibrillation under sufficient medical treatment in patient with coronary artery spasm. | In cases of coronary artery spasm, life-threatening ventricular arrhythmias are possible and can lead to sudden cardiac death. Treatment for this condition includes implantable cardioverter defibrillators, but their effectiveness in patients who present with ventricular fibrillation is debated. Our patient presented with intractable ventricular fibrillation episodes that triggered shocks from her implanted defibrillator. At 2 years of follow-up, we placed her on 200 mg/day of oral amiodarone, after identifying short-coupled premature contractions as the trigger for the ventricular fibrillation. In the 2 years following initiation of this drug therapy, the patient had no further fibrillation episodes. |
12,890 | Effect of mild hypothermia on the coagulation-fibrinolysis system and physiological anticoagulants after cardiopulmonary resuscitation in a porcine model. | The aim of this study was to evaluate the effect of mild hypothermia on the coagulation-fibrinolysis system and physiological anticoagulants after cardiopulmonary resuscitation (CPR). A total of 20 male Wuzhishan miniature pigs underwent 8 min of untreated ventricular fibrillation and CPR. Of these, 16 were successfully resuscitated and were randomized into the mild hypothermia group (MH, n = 8) or the control normothermia group (CN, n = 8). Mild hypothermia (33°C) was induced intravascularly, and this temperature was maintained for 12 h before pigs were actively rewarmed. The CN group received normothermic post-cardiac arrest (CA) care for 72 h. Four animals were in the sham operation group (SO). Blood samples were taken at baseline, and 0.5, 6, 12, 24, and 72 h after ROSC. Whole-body mild hypothermia impaired blood coagulation during cooling, but attenuated blood coagulation impairment at 72 h after ROSC. Mild hypothermia also increased serum levels of physiological anticoagulants, such as PRO C and AT-III during cooling and after rewarming, decreased EPCR and TFPI levels during cooling but not after rewarming, and inhibited fibrinolysis and platelet activation during cooling and after rewarming. Finally, mild hypothermia did not affect coagulation-fibrinolysis, physiological anticoagulants, or platelet activation during rewarming. Thus, our findings indicate that mild hypothermia exerted an anticoagulant effect during cooling, which may have inhibitory effects on microthrombus formation. Furthermore, mild hypothermia inhibited fibrinolysis and platelet activation during cooling and attenuated blood coagulation impairment after rewarming. Slow rewarming had no obvious adverse effects on blood coagulation. |
12,891 | Network interactions within the canine intrinsic cardiac nervous system: implications for reflex control of regional cardiac function. |   The aims of the study were to determine how aggregates of intrinsic cardiac (IC) neurons transduce the cardiovascular milieu versus responding to changes in central neuronal drive and to determine IC network interactions subsequent to induced neural imbalances in the genesis of atrial fibrillation (AF). Activity from multiple IC neurons in the right atrial ganglionated plexus was recorded in eight anaesthetized canines using a 16-channel linear microelectrode array. Induced changes in IC neuronal activity were evaluated in response to: (1) focal cardiac mechanical distortion; (2) electrical activation of cervical vagi or stellate ganglia; (3) occlusion of the inferior vena cava or thoracic aorta; (4) transient ventricular ischaemia, and (5) neurally induced AF. Low level activity (ranging from 0 to 2.7 Hz) generated by 92 neurons was identified in basal states, activities that displayed functional interconnectivity. The majority (56%) of IC neurons so identified received indirect central inputs (vagus alone: 25%; stellate ganglion alone: 27%; both: 48%). Fifty per cent transduced the cardiac milieu responding to multimodal stressors applied to the great vessels or heart. Fifty per cent of IC neurons exhibited cardiac cycle periodicity, with activity occurring primarily in late diastole into isovolumetric contraction. Cardiac-related activity in IC neurons was primarily related to direct cardiac mechano-sensory inputs and indirect autonomic efferent inputs. In response to mediastinal nerve stimulation, most IC neurons became excessively activated; such network behaviour preceded and persisted throughout AF. It was concluded that stochastic interactions occur among IC local circuit neuronal populations in the control of regional cardiac function. Modulation of IC local circuit neuronal recruitment may represent a novel approach for the treatment of cardiac disease, including atrial arrhythmias. |
12,892 | Computed tomography and echocardiography together reveal more high-risk findings than echocardiography alone in the diagnostics of stroke etiology. | Cardioembolic stroke carries a major risk of stroke recurrence, which can be markedly reduced by early initiation of appropriate secondary prevention. We investigate whether combined examination of the heart, aorta, and cervicocranial arteries with computed tomography (CACC-CT) may improve the diagnosis of stroke etiology.</AbstractText>Patients with suspected cardiogenic ischemic stroke or transient ischemic attack (n = 140; mean age 60 ± 10 years; 95 males) underwent CACC-CT and standard diagnostics including transthoracic and transesophageal echocardiography (TTE/TEE). Patients with atrial fibrillation were excluded because cardiac imaging will not affect to anticoagulant treatment. Imaging findings with a potential cardioembolic source were analyzed. Aortic and cardiac risk findings were evaluated independently. Consensus reading of 2 experts using the findings of both approaches and complemented by cardiac MRI when needed served as the reference standard.</AbstractText>In 101 patients (72%) the clinical diagnosis was stroke, and transient ischemic attack was confirmed in the remaining patients. Imaging findings associated with highly increased cardioembolic risk were detected in 22 patients (16%). Nine high-risk findings in 140 patients were found by TTE/TEE and this number rose to 25 high after performing both echocardiography and CACC-CT. No difference was found between CACC-CT and TTE/TEE in detecting patients with of at least one high-risk findings (sensitivity 68 vs. 41%, p = 0.052; specificity 98 vs. 99%; overall accuracy 94 vs. 90%). Combined use of CACC-CT and TTE/TEE was more sensitive than TTE/TEE alone for detecting patients with at least one cardiac or aortic high-risk finding (sensitivity 91 vs. 41%, p < 0.001; specificity 98 vs. 99%; overall accuracy 97 vs. 90%). TTE/TEE was insufficient for diagnosing myocardial infarction with left ventricular aneurysm, whereas the accuracy of CACC-CT was high. In 9 patients (6%) with normal or mild hypokinesia in TTE/TEE, CACC-CT and MRI showed myocardial infarction large enough to indicate anticoagulant therapy. In contrast, CACC-CT was not suitable for diagnosing small left artrial thrombi, patent foramen ovale or to measure left ventricular ejection fraction.</AbstractText>CACC-CT and TTE/TEE alone show limited accuracy for the diagnostics of stroke etiology. Therefore, CACC-CT could be a valuable tool in patients with cryptogenic stroke despite standard stroke diagnostics.</AbstractText>Copyright © 2013 S. Karger AG, Basel.</CopyrightInformation> |
12,893 | A unique access for the ablation catheter to treat electrical storm in a patient with extracorporeal life support. | Extracorporeal membrane oxygenation (ECMO) is a very effective bridging therapy in patients with cardiogenic shock. To perform coronary angiography in these patients our group developed an unique system to get urgent vascular access with minimal additional vascular complication risk. The 6 Fr coronary catheters are introduced through a standard Y-connector, which is inserted into the arterial cannula of the ECMO-line close to the patient, the blind end of which is then equipped with a haemostatic valve (Check-Flo Performer accessory adapter, Cook Medical, USA). To the best of our knowledge, we here present the first patient, in whom this system had been used to insert an 8 Fr radiofrequency ablation catheter to treat incessant ventricular fibrillation.</AbstractText>A 66-year-old patient had been transferred with electrical storm 5 days after an acute MI. After failed interventional and medical therapies an ECMO system had been inserted (right femoral artery cannula 15 Fr, left femoral vein cannula 21 Fr) and an electrophysiological study had been performed because of incessant ventricular fibrillation episodes, which always were induced by the same ventricular premature beat (VPB). During this first EP study over the left femoral artery the VPB could be targeted and successfully ablated. Unfortunately the VPB recovered again after some days so a second EP study had to be performed. This time the left femoral artery could not be used because of a postinterventional complication so we used the arterial cannula of the ECMO system as the access for the ablation catheter using a Y-connector. Using this way again a successful ablation procedure could be performed, after getting familiar with manipulation the ablation catheter over the ECMO cannula and with the help of different curved ablation catheters. The issue of compromising of the effective lumen of the arterial cannula by the ablation catheter`s cross sectional area could be overcome with increasing the rotational speed of the V-A ECMO.</AbstractText>Ablation of ventricular arrhythmias using a Y-connector to insert the ablation catheter into the arterial cannula is feasible in patients with a V-A ECMO system avoiding additional arterial puncture with potentially major vascular complications in critically ill patients. Manipulation of the catheter is not as easy as using a standard sheath but can well be performed after a short habituation.</AbstractText> |
12,894 | Malignant arrhythmogenic right ventricular dysplasia/cardiomyopathy with a normal 12-lead electrocardiogram: a rare but underrecognized clinical entity. | In Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C), a normal electrocardiogram (ECG) is considered reassuring. However, some patients with ARVD/C experiencing ventricular arrhythmias have a normal ECG.</AbstractText>To estimate how often patients with ARVD/C experiencing ventricular arrhythmias have a normal ECG during sinus rhythm, and to provide a clinical profile of these patients.</AbstractText>We included 145 patients with ARVD/C experiencing a documented sustained ventricular arrhythmia. Conventional 12-lead sinus rhythm ECGs within 6 months of the event were reviewed for diagnostic Task Force Criteria (TFC). ECGs were classified as abnormal (≥1 TFC), nonspecific (abnormal, no TFC), or normal. Cardiologic investigations within 6 months of the event were evaluated as per TFC in those with a nonspecific or normal ECG.</AbstractText>The ECG was nonspecific or normal in 17 of 145 (12%) subjects. Mean age of these patients was 41.3 ± 12.4 years and 14 (82%) were men, comparable to those with an abnormal ECG. Most patients with a nonspecific or normal ECG showed ≥1 TFC on Holter monitoring (n = 9 of 10) and signal-averaged ECG (n = 4 of 5), and all had nonsustained ventricular tachycardia recorded. Among 15 patients who underwent structural evaluation, 11 (73%) showed structural TFC (9 major and 2 minor).</AbstractText>Although most patients with ARVD/C experiencing arrhythmias have an abnormal ECG, a nonspecific or normal ECG does not preclude ARVD/C diagnosis. All patients with a nonspecific or normal ECG had alternative evidence of disease expression. These results alert the physician not to rely exclusively on ECG in ARVD/C, but to assess arrhythmic risk by comprehensive clinical evaluation.</AbstractText>© 2013 Heart Rhythm Society. All rights reserved.</CopyrightInformation> |
12,895 | [A case of late drug-eluting stent thrombosis during postoperative period after 5 years of stent implantation]. | Stent thrombosis during perioperative period is a critical complication for patients treated with drug-eluting stent (DES). We experienced a case of late DES thrombosis 5 years after initial implantation. A 48-year-old man with familial hyperlipidemia, angina pectoris and chronic pulmonary emphysema, was diagnosed with esophageal carcinoma, and scheduled for esophagectomy. He was first treated with DES 5 years ago, and he underwent repeated revascularization for re-stenosis. He had received anti-platelet therapy up to 1 week prior to the current operation, which was replaced by heparin administration. The surgical procedure was uneventful, and he tolerated it well. Immediately after his admission to ICU, sporadic premature ventricular contraction and ST-elevation occurred, leading to ventricular fibrillation. Emergent coronary angiography revealed re-stenosis of the right coronary artery treated with DES 5 years ago. At present, there was no definite guideline, on the management of DES during perioperative period. It is important for us to decide continuing antiplatelet therapy balancing the risk of stent thrombosis with surgical bleeding in each patient. |
12,896 | ECG Changes in Smokers and Non Smokers-A Comparative Study. | Tobacco consumption is the single most cause of the preventable deaths globally. Tobacco is consumed in the form of cigarettes. It contains nicotine which causes physical and psychological dependencies. Cigarette smoking increases the blood coagulability. Nicotine facilitates conduction block, re-entry and it increases the vulnerability to ventricular fibrillation. Hence, Nicotine and other components of cigarette can produce profound changes in the heart, which can be assessed by doing an ECG, which is the, cheapest and the most reliable method for assessing cardiovascular abnormalities.</AbstractText>To compare the ECG changes between smokers and non- smokers.</AbstractText>Eighty eight healthy male volunteers who were in the age group of 18-30 years, who attended the outpatients department of SBMCH were recruited for the study. Among the volunteers, 44 were smokers as per the ICD-10 criteria for substance abuse and the rest of the 44 were non-smoker subjects without any systemic illnesses and a drug and alcohol intake.</AbstractText>After a thorough examination, all the subjects were asked to abstain from smoking and caffeine beverages, 2 hours prior to the taking of the ECG recording. The ECG was recorded in the lab of the Department of Physiology of SBMCH. The following parameters were assessed, namely, the heart rate, the p- wave, the PR interval and the QRS complex. The QTc (corrected QT interval) was calculated by using Bazet's formula. The QT interval, the ST segment and the T wave duration were evaluated in seconds. The results which were obtained were statistically analyzed by using the Students 't' test.</AbstractText>The analysis showed that QTc interval was shortened and that the QRS complex duration was widened in the smokers, although the values did not show any statistical significance. The heart rate was increased in the smokers, which was statistically significant. The RR interval, the QT interval and the ST segment were shortened in the smokers as compared to those in the non smokers, which was highly significant statistically.</AbstractText>All the above changes in our study were either a result of the acute effects or the chronic effects of smoking, which led to cardiovascular disorders which could be easily identified by the wave duration in electrocardiography. This may be used by physicians as a tool for counselling the smokers to stop smoking as early as possible. Smoking even a sin.</AbstractText> |
12,897 | Chronic atrial fibrillation causes left ventricular dysfunction in dogs but not goats: experience with dogs, goats, and pigs. | Structural remodeling in chronic atrial fibrillation (AF) occurs over weeks to months. To study the electrophysiological, structural, and functional changes that occur in chronic AF, the selection of the best animal model is critical. AF was induced by rapid atrial pacing (50-Hz stimulation every other second) in pigs (n = 4), dogs (n = 8), and goats (n = 9). Animals underwent MRIs at baseline and 6 mo to evaluate left ventricular (LV) ejection fraction (EF). Dogs were given metoprolol (50-100 mg po bid) and digoxin (0.0625-0.125 mg po bid) to limit the ventricular response rate to <180 beats/min and to mitigate the effects of heart failure. The pacing leads in pigs became entirely encapsulated and lost the ability to excite the heart, often before the onset of sustained AF. LV EF in dogs dropped from 54 ± 11% at baseline to 33 ± 7% at 6 mo (P < 0.05), whereas LV EF in goats did not drop significantly (69 ± 8% at baseline vs. 60 ± 9% at 6 mo, P = not significant). After 6 mo of AF, fibrosis levels in dog atria and ventricles increased, whereas only atrial fibrosis levels increased in goats compared with control animals. In our experience, the pig model is not appropriate for chronic rapid atrial pacing-induced AF studies. Rate-controlled chronic AF in the dog model developed HF and LV fibrosis, whereas the goat model developed only atrial fibrosis without ventricular dysfunction and fibrosis. Both the dog and goat models are representative of segments of the patient population with chronic AF. |
12,898 | Prolonged preconditioning with natural honey against myocardial infarction injuries. | Potential protective effects of prolonged preconditioning with natural honey against myocardial infarction were investigated. Male Wistar rats were pre-treated with honey (1%, 2% and 4%) for 45 days then their hearts were isolated and mounted on a Langendorff apparatus and perfused with a modified Krebs-Henseleit solution during 30 min regional ischemia fallowed by 120 min reperfusion. Two important indexes of ischemia-induced damage (infarction size and arrhythmias) were determined by computerized planimetry and ECG analysis, respectively. Honey (1% and 2%) reduced infarct size from 23±3.1% (control) to 9.7±2.4 and 9.5±2.3%, respectively (P<0.001). At the ischemia, honey (1%) significantly reduced (P<0.05) the number and duration of ventricular tachycardia (VT). Honey (1% and 2%) also significantly decreased number of ventricular ectopic beats (VEBs). In addition, incidence and duration of reversible ventricular fibrillation (Rev VF) were lowered by honey 2% (P<0.05). During reperfusion, honey produced significant reduction in the incidences of VT, total and Rev VF, duration and number of VT. The results showed cardioprotective effects of prolonged pre-treatment of rats with honey following myocardial infarction. Maybe, the existence of antioxidants and energy sources (glucose and fructose) in honey composition and improvement of hemodynamic functions may involve in those protective effects. |
12,899 | Sinus rhythm restores ventricular function in patients with cardiomyopathy and no late gadolinium enhancement on cardiac magnetic resonance imaging who undergo catheter ablation for atrial fibrillation. | Atrial fibrillation (AF) and systolic heart failure (HF) frequently coexist. Restoration of sinus rhythm by catheter ablation may result in a variable improvement in left ventricular (LV) function. Late-gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) imaging identifies irreversible structural change and may predict incomplete recovery of LV function.</AbstractText>To prospectively select patients with AF and symptomatic HF but without LV LGE and report the impact of AF ablation on LV function.</AbstractText>Patients with AF and symptomatic HF (LV ejection fraction <50%) resistant to at least 1 antiarrhythmic drug and prior electrical cardioversion underwent contrast-enhanced CMR. LGE-negative patients underwent pulmonary vein isolation and left atrial roof line with continued antiarrhythmic medications until follow-up CMR 6 months postablation. Sixteen patients (aged 52 ± 11 years; mean AF duration 37 ± 39 months; left atrial size 44 ± 13 mL/m(2)) underwent AF ablation.</AbstractText>At 6 months, 15 of the 16 patients maintained sinus rhythm and underwent CMR. LV ejection fraction increased from 40% ± 10% at baseline to 60% ± 6% (P < .001) and LV end-systolic volume index decreased from 52 ± 12 to 36 ± 9 mL/m(2) (P < .001). Left atrial size decreased from 44 ± 13 to 36 ± 11 mL/m(2) (P < .01).</AbstractText>In patients with AF and LV dysfunction in the absence of LGE on CMR, ventricular function normalizes following the restoration of sinus rhythm. CMR may assist in the selection of patients with combined AF and systolic HF most likely to benefit from catheter ablation.</AbstractText>Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
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