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13,700 | Left atrial strain is reduced in patients with atrial fibrillation, stroke or TIA, and low risk CHADS(2) scores. | Left atrial (LA) strain as a marker for discrimination of risk for stroke and transient ischemic attack (TIA) in patients with atrial fibrillation and low-risk CHADS(2) scores (≤1) has yet to be examined.</AbstractText>Patients with atrial fibrillation, stroke or TIA, and CHADS(2) scores ≤ 1 before their events were identified retrospectively from a large single-center stroke registry and compared with age-matched and gender-matched controls. Antihypertensive use and echocardiographic parameters including chamber volumes and left ventricular mass and LA peak negative and positive strain and strain rate were compared between groups.</AbstractText>Fifty-seven patients meeting entry criteria were identified. Patients demonstrated significantly lower left ventricular ejection fractions, larger LA dimensions, and larger LA volume indexes (24.4 ± 11.9 vs 32.3 ± 13.3 mL/m(2), P = .012) compared with controls. Both peak negative LA strain (-3.2 ± 1.2% vs -6.9 ± 4.2%, P < .001) and peak positive LA strain (14 ± 11% vs 25 ± 12%, P < .001) were significantly reduced in patients compared with controls. Peak negative LA strain was significantly associated with stroke by binary logistic regression (odds ratio, 2.15; P < .001).</AbstractText>In patients with low-risk CHADS(2) scores, atrial fibrillation, and stroke or TIA, reduced LA strain is a potentially sensitive maker for increased risk for stroke or TIA. These results suggest that LA strain may have potential as a tool for helping guide the decision for or against oral anticoagulation in this group of patients.</AbstractText>Copyright © 2012 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
13,701 | Non-linear dynamical signal characterization for prediction of defibrillation success through machine learning. | Ventricular Fibrillation (VF) is a common presenting dysrhythmia in the setting of cardiac arrest whose main treatment is defibrillation through direct current countershock to achieve return of spontaneous circulation. However, often defibrillation is unsuccessful and may even lead to the transition of VF to more nefarious rhythms such as asystole or pulseless electrical activity. Multiple methods have been proposed for predicting defibrillation success based on examination of the VF waveform. To date, however, no analytical technique has been widely accepted. We developed a unique approach of computational VF waveform analysis, with and without addition of the signal of end-tidal carbon dioxide (PetCO2), using advanced machine learning algorithms. We compare these results with those obtained using the Amplitude Spectral Area (AMSA) technique.</AbstractText>A total of 90 pre-countershock ECG signals were analyzed form an accessible preshosptial cardiac arrest database. A unified predictive model, based on signal processing and machine learning, was developed with time-series and dual-tree complex wavelet transform features. Upon selection of correlated variables, a parametrically optimized support vector machine (SVM) model was trained for predicting outcomes on the test sets. Training and testing was performed with nested 10-fold cross validation and 6-10 features for each test fold.</AbstractText>The integrative model performs real-time, short-term (7.8 second) analysis of the Electrocardiogram (ECG). For a total of 90 signals, 34 successful and 56 unsuccessful defibrillations were classified with an average Accuracy and Receiver Operator Characteristic (ROC) Area Under the Curve (AUC) of 82.2% and 85%, respectively. Incorporation of the end-tidal carbon dioxide signal boosted Accuracy and ROC AUC to 83.3% and 93.8%, respectively, for a smaller dataset containing 48 signals. VF analysis using AMSA resulted in accuracy and ROC AUC of 64.6% and 60.9%, respectively.</AbstractText>We report the development and first-use of a nontraditional non-linear method of analyzing the VF ECG signal, yielding high predictive accuracies of defibrillation success. Furthermore, incorporation of features from the PetCO2 signal noticeably increased model robustness. These predictive capabilities should further improve with the availability of a larger database.</AbstractText> |
13,702 | Distribution and clinical correlates of the interleukin receptor family member soluble ST2 in the Framingham Heart Study. | Soluble ST2 (sST2) is a cardiac biomarker whose concentration rises in response to myocardial strain. Increased sST2 concentrations may predict adverse outcomes in patients with heart failure and myocardial infarction. Because sST2 was largely undetectable with first-generation assays in ambulatory individuals, there are few data regarding its distribution and correlates in community-based populations.</AbstractText>We measured sST2 using a highly sensitive ELISA in 3450 Framingham Heart Study participants who attended a routine examination. We used multivariable linear regression models to identify covariates associated with sST2 in the general sample. We obtained a reference sample (n = 1136) by excluding individuals with prevalent coronary disease, heart failure, atrial fibrillation, diabetes, hypertension, obesity, valvular disease, left ventricular systolic dysfunction, and pulmonary and renal dysfunction. We used empiric and quantile regression techniques to estimate the 2.5th, 50th, 97.5th, and 99th quantiles.</AbstractText>In the general sample (mean age 59 years, 55% women), systolic blood pressure (P = 0.006), antihypertensive medication use (P = 0.03), and diabetes (P < 0.001) were associated with sST2 concentrations. In the reference sample (mean age 55, 59% women), male sex (P < 0.0001) and older age (P = 0.004) were predictive of higher sST2 concentrations. Quantile and empirical methods were used to define the reference intervals. Using the empirical approach, upper 99% percentile values in different age groups ranged from 46.6 to 64.4 μg/L in men and 36.7 to 53.0 μg/L in women.</AbstractText>In a well-characterized, community-based cohort, values for sST2 differ between men and women, increase with age, and are associated with diabetes and hypertension.</AbstractText>© 2012 American Association for Clinical Chemistry</CopyrightInformation> |
13,703 | The effect of pinacidil on postshock activation and ventricular defibrillation threshold in canine hearts. | To determine the postshock activation patterns with both successful and failed shocks in a canine model of ventricular fibrillation, and whether piniacidil, an early after-depolarization (EAD) inhibitor, altered the defibrillation threshold (DFT) and postshock activation patterns.</AbstractText>In 6 beagles, a basket catheter with 64 unipolar electrodes was placed in the LV for global endocardial mapping, a monophasic action potential catheter was inserted into the LV apex, and a catheter with the negative electrode in the right ventricle and the positive electrode in the superior vena cava was inserted for defibrillation. The DFT, 90% action potential duration (APD(90)) and activation recovery interval (ARI) were evaluated before and after pinacidil administration (loading dosage 0.5 mg/kg and maintenance dosage 0.5 mg·kg(-1)·h(-1), iv). Electrical heterogeneities were defined with the dispersion of ARI. After successful and failed shocks with near-DFT strength, the earliest postshock activation patterns (focal or nonfocal endocardial activation), interval and location were detected.</AbstractText>Pinacidil significantly decreased APD(90) (from 178±16 ms to 168±18 ms) and ARI from (152±10 ms to 143±10 ms) at pacing cycle length of 300 ms. The drug significantly increased VF activation rate (from 10.0±1.9 Hz to 10.8±2.0 Hz). The drug did not affect the dispersion of ARI, neither it changed DFT (baseline: 480±110 V; pinacidil: 425±55 V, P>0.05). The earliest postshock activation arose locally on the LV apical endocardium before and after the drug treatment. Pinacidil significantly prolonged the postshock cycle length of cycles 2 to 5 for the successful episodes but not for the failed episodes.</AbstractText>Pinacidil increases the postshock cycle length suggesting that EAD may play a role in postshock activation, while it fails to alter DFT suggesting that EAD produced by shock does not determine a defibrillation success or failure.</AbstractText> |
13,704 | Role of microRNAs in cardiac remodelling: new insights and future perspectives. | Cardiac remodelling is a key process in the progression of cardiovascular disease, implemented in myocardial infarction, valvular heart disease, myocarditis, dilated cardiomyopathy, atrial fibrillation and heart failure. Fibroblasts, extracellular matrix proteins, coronary vasculature, cardiac myocytes and ionic channels are all involved in this remodelling process. MicroRNAs (miRNAs) represent a sizable sub-group of small non-coding RNAs, which degrade or inhibit the translation of their target mRNAs, thus regulating gene expression and play an important role in a wide range of biologic processes. Recent studies have reported that miRNAs are aberrantly expressed in the cardiovascular system under some pathological conditions. Indeed, in vitro and in vivo models have revealed that miRNAs are essential for cardiac development and remodelling. Clinically, there is increasing evidence of the potential diagnostic role of miRNAs as potential diagnostic biomarkers and they may represent a novel therapeutic target in several cardiovascular disorders. This paper provides an overview of the impact of several miRNAs in electrical and structural remodelling of the cardiac tissue, and the diagnostic and therapeutic potential of miRNA in cardiovascular disease. |
13,705 | Hemodynamic and catecholamine changes after recurrent ventricular fibrillation. | Patients with recurrent ventricular fibrillation (VF) have a high mortality rate, which may be partly due to hemodynamic instability.</AbstractText>The aim of this study was to simulate spontaneous recurrent VF by repeated induction of VF in pigs, and to evaluate the subsequent changes in heart rate (HR), blood pressure (BP), and serum catecholamine levels.</AbstractText>VF was induced four times in each of eight female pigs. Defibrillation was first attempted at 30 s after induction of each episode of VF. Circulation was allowed to stabilize for 30 min after return of spontaneous circulation (ROSC) before induction of the next episode of VF. HR and BP were measured before each induction of VF and at 1 min after each ROSC, and venous blood was drawn at the same times to measure serum catecholamine levels.</AbstractText>VF was induced a total of 32 times. Serum epinephrine (EPI) and norepinephrine (NE) levels decreased (p all < 0.05) and dopamine (DA) levels gradually increased (p < 0.05) with repeated episodes of VF. Compared with baseline values before each episode of VF, BP increased significantly at 1 min after ROSC (p all < 0.05) and then gradually returned to baseline values. HR increased significantly after the first ROSC and stayed elevated. No significant correlations were found between catecholamine levels and HR or BP.</AbstractText>With repeated episodes of VF, BP increased transiently and then gradually returned to baseline values, but HR stayed elevated. Serum DA levels increased, EPI and NE levels gradually decreased.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,706 | Echocardiographic prediction of postoperative atrial fibrillation after aortic valve replacement for aortic stenosis: a two-dimensional speckle tracking left ventricular longitudinal strain multicentre pilot study. | Postoperative atrial fibrillation (POAF) is a common complication after cardiac surgery, with increased risk of embolic events, haemodynamic instability, haemorrhagic complications and prolonged hospital stay.</AbstractText>We sought to assess the value of preoperative left ventricular global longitudinal strain (GLS) for the prediction of POAF in a series of patients with severe symptomatic aortic stenosis who underwent aortic valve replacement (AVR).</AbstractText>Fifty-eight consecutive patients (52% men) aged 73±9 years, with severe symptomatic aortic stenosis (aortic valve area<1cm(2) or<0.5cm(2)/m(2)), in sinus rhythm, who underwent AVR were prospectively included in three centres between 2009 and 2010. Complete preoperative echocardiography was performed in all patients, including global and segmental longitudinal strain using two-dimensional speckle tracking.</AbstractText>The POAF incidence was 28/58 (48%). On univariate analysis, aortic valve area (P=0.04), preoperative E/e' ratio (P=0.04) and GLS (P=0.005) were associated with the occurrence of POAF. Chronic obstructive pulmonary disease (P=0.05), preoperative statin treatment (P=0.09), age≥80 years (P=0.09), left ventricular ejection fraction (P=0.09) and systolic pulmonary artery pressure (P=0.06) tended to increase the risk of POAF. The best GLS cut-off value for the prediction of POAF was -15% (82% sensitivity, 53% specificity, area under the curve 0.72). On multivariable analysis, GLS>-15% was the only independent predictor of POAF (odds ratio 7.74, 95% confidence interval [1.15-52.03]; P=0.035).</AbstractText>Incidence of POAF is high after AVR for severe aortic stenosis. Our results suggest an additive value of the study of left ventricular myocardial deformation to classical clinical and echocardiographic variables for the prediction of POAF in this setting.</AbstractText>Copyright © 2012. Published by Elsevier Masson SAS.</CopyrightInformation> |
13,707 | Tissue Doppler imaging and prognosis in asymptomatic or mildly symptomatic patients with hypertrophic cardiomyopathy. | Assessment of left ventricular (LV) systolic and diastolic functions by tissue Doppler imaging (TDI) has been reported to be useful for predicting the prognosis in patients with hypertrophic cardiomyopathy (HCM). The purpose of this study was to evaluate the clinical significance of TDI parameters for the prediction of cardiovascular events in asymptomatic or mildly symptomatic patients with HCM.</AbstractText>Eighty-five HCM patients (52 males, 55.6 ± 14.8 years.) belonging to the New York Heart Association (NYHA) functional class I or II were enrolled in this study. Patients with the LV systolic dysfunction or a clinically documented history of atrial fibrillation were excluded. The combined endpoints were HCM-related death; admission for heart failure or stroke; new episode of atrial fibrillation; and worsening of heart failure symptoms (NYHA class III). During a follow-up period of 4.5 ± 1.7 years, 11 patients achieved the combined endpoints. Patients who experienced cardiovascular events had a larger LV size and left atrial volume compared with those who did not. Peak systolic, early diastolic (e'), and late diastolic TDI velocities at the septal corner were lower in patients who experienced cardiovascular events; moreover, the septal E/e' value was higher in these patients. Multivariate forward regression analysis revealed the deceleration times of E and the septal E/e' to be independent predictors of cardiovascular events.</AbstractText>Assessment of the diastolic function by TDI is useful for risk stratification in HCM patients with no or mild symptoms. TDI measurements should be incorporated into the clinical management of HCM.</AbstractText> |
13,708 | MK-0448, a specific Kv1.5 inhibitor: safety, pharmacokinetics, and pharmacodynamic electrophysiology in experimental animal models and humans. | We evaluated the viability of I(Kur) as a target for maintenance of sinus rhythm in patients with a history of atrial fibrillation through the testing of MK-0448, a novel I(Kur) inhibitor.</AbstractText>In vitro MK-0448 studies demonstrated strong inhibition of I(Kur) with minimal off-target activity. In vivo MK-0448 studies in normal anesthetized dogs demonstrated significant prolongation of the atrial refractory period compared with vehicle controls without affecting the ventricular refractory period. In studies of a conscious dog heart failure model, sustained atrial fibrillation was terminated with bolus intravenous MK-0448 doses of 0.03 and 0.1 mg/kg. These data led to a 2-part first-in-human study: Part I evaluated safety and pharmacokinetics, and part II was an invasive electrophysiological study in healthy subjects. MK-0448 was well-tolerated with mild adverse experiences, most commonly irritation at the injection site. During the electrophysiological study, ascending doses of MK-0448 were administered, but no increases in atrial or ventricular refractoriness were detected, despite achieving plasma concentrations in excess of 2 μmol/L. Follow-up studies in normal anesthetized dogs designed to assess the influence of autonomic tone demonstrated that prolongation of atrial refractoriness with MK-0448 was markedly attenuated in the presence of vagal nerve simulation, suggesting that the effects of I(Kur) blockade on atrial repolarization may be negated by enhanced parasympathetic neural tone.</AbstractText>The contribution of I(Kur) to human atrial electrophysiology is less prominent than in preclinical models and therefore is likely to be of limited therapeutic value for the prevention of atrial fibrillation.</AbstractText> |
13,709 | CaMKII inhibition rescues proarrhythmic phenotypes in the model of human ankyrin-B syndrome. | Cardiovascular disease is a leading cause of death worldwide. Arrhythmias are associated with significant morbidity and mortality related to cardiovascular disease. Recent work illustrates that many cardiac arrhythmias are initiated by a pathologic imbalance between kinase and phosphatase activities in excitable cardiomyocytes.</AbstractText>To test the relationship between myocyte kinase/phosphatase imbalance and cellular and whole animal arrhythmia phenotypes associated with ankyrin-B cardiac syndrome.</AbstractText>By using a combination of biochemical, electrophysiological, and in vivo approaches, we tested the ability of calcium/calmodulin-dependent kinase (CaMKII) inhibition to rescue imbalance in kinase/phosphatase pathways associated with human ankyrin-B-associated cardiac arrhythmia.</AbstractText>The cardiac ryanodine receptor (RyR(2)), a validated target of kinase/phosphatase regulation in myocytes, displays abnormal CaMKII-dependent phosphorylation (pS2814 hyperphosphorylation) in ankyrin-B(+/-) heart. Notably, RyR(2) dysregulation is rescued in myocytes from ankyrin-B(+/-) mice overexpressing a potent CaMKII-inhibitory peptide (AC3I), and aberrant RyR(2) open probability observed in ankyrin-B(+/-) hearts is normalized by treatment with the CaMKII inhibitor KN-93. CaMKII inhibition is sufficient to rescue abnormalities in ankyrin-B(+/-) myocyte electrical dysfunction including cellular afterdepolarizations, and significantly blunts whole animal cardiac arrhythmias and sudden death in response to elevated sympathetic tone.</AbstractText>These findings illustrate the complexity of the molecular components involved in human arrhythmia and define regulatory elements of the ankyrin-B pathway in pathophysiology. Furthermore, the findings illustrate the potential impact of CaMKII inhibition in the treatment of a congenital form of human cardiac arrhythmia.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,710 | [Stroke and Takotsubo syndrome: a reciprocal relationship]. | Takotsubo syndrome is a transient stress cardiomyopathy associated with a distinctive left ventricular contraction pattern. It has been described as a cardioembolic source or as a consequence of stroke. Two patients are reported that illustrate the reciprocal relationship between Takotsubo syndrome and stroke and the physiopathological mechanisms implicated are analyzed.</AbstractText>Two women aged 70 and 78 years respectively are described. The first one was admitted with electro-cardiogram ST-segment elevation, slight troponin elevation and stroke symptoms. Ecocardiography and cardiac magnetic resonance findings were consistent with Takotsubo syndrome that was the probable source of cardioembolic stroke. The second patient suffered a Takotsubo syndrome 72 hours after a brain infarction involving the insular cortex that was considered the trigger of Takotsubo syndrome.</AbstractText>Takotsubo syndrome and stroke may have a reciprocal etiological relationship that is suggested by the temporal profile between the two processes. Cardiac magnetic resonance may aid in the establishment of the diagnosis of Takotsubo syndrome.</AbstractText> |
13,711 | Left ventricular lead location and the risk of ventricular arrhythmias in the MADIT-CRT trial. | We aimed to evaluate the influence of left ventricular (LV) lead position on the risk of ventricular tachyarrhythmias in cardiac resynchronization therapy (CRT) patients.</AbstractText>Left ventricular (LV) lead position was evaluated by biplane coronary venograms and anterior/posterior, lateral chest X-rays in patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial - Cardiac Resynchronization Therapy (MADIT-CRT). The LV lead location could be defined in 797 of 1089 patients (73%). The LV lead was placed at the LV apex in 110 (14%) patients, in the anterior position in 146 (18%), in the lateral position in 448 (56%), and in the posterior position in 93 (12%) patients. After adjustment for clinical covariates, lateral or posterior lead location was associated with significantly lower risk of ventricular tachycardia (VT)/ventricular fibrillation (VF) [hazard ratio (HR) = 0.57, 95% confidence interval (CI): 0.38-0.85; P = 0.006] when compared with an anterior lead location. Patients with anterior lead position had similar risk of VT/VF as patients with implantable cardioverter defibrillator (ICD)-only (HR = 1.04, 95% CI: 0.72-1.81; P = 0.837). There was no difference in the risk of mortality between posterior or lateral and anterior LV lead locations.</AbstractText>Cardiac resynchronization therapy with posterior or lateral LV lead position is associated with decreased risk of arrhythmic events in comparison with anterior lead location and ICD-only patients. There is no evidence for increased risk of VT/VF episodes associated with CRT.</AbstractText> |
13,712 | Triphasic mitral and tricuspid flows: a sign of diastolic dysfunction in a young patient with severely dilated atria and giant pulmonary veins. | This report presents a case with severe dilation of both atria and giant pulmonary veins manifested with atrial fibrillation. The following cardiac magnetic resonance findings are highly suggestive of restrictive physiology: E/A ratio greater than two, prominent A wave across the pulmonary veins and inferior vena cava, and more interestingly, a triphasic flow across the mitral and tricuspid valves. |
13,713 | Direct comparison of percutaneous circulatory support systems in specific hemodynamic conditions in a porcine model. | Several percutaneous circulatory support systems have been recently introduced into clinical practice for the treatment of cardiogenic shock or refractory nontolerated ventricular tachycardia, in support of high-risk catheter interventions and, occasionally, cardiopulmonary resuscitation. To date, however, a direct comparison of the available systems has not been performed.</AbstractText>Adult female pigs (weight 50-60 kg) were used throughout the experiment. Under deep anesthesia and mechanical ventilation, 3 percutaneous circulatory support systems were compared: (1) right atrium-aorta, extracorporeal membrane oxygenation (n=4); (2) left atrium-aorta, TandemHeart system (n=4); (3) left ventricle-aorta, Impella 2.5 system (n=4), and (4) left ventricle-aorta with norepinephrine at 0.1 µg/kg per minute (n=4). Hemodynamic efficacy (mean arterial pressure) was measured at 3 specific conditions: ventricular pacing at 200 and 300 beats per minute, and ventricular fibrillation. Although no or only nonsignificant differences were found among the systems at ventricular pacing of 200 and 300 beats per minute, under ventricular fibrillation, the right atrium-aorta system was significantly the most efficacious, followed by the left atrium-aorta system and the left ventricle-aorta system (P<0.001). However, the left ventricle-aorta system with norepinephrine still maintained mean arterial pressure comparable with the left atrium-aorta system.</AbstractText>Differences were seen in the hemodynamic efficacy of available percutaneous circulatory support systems, particularly under the most severe hemodynamic condition, ventricular fibrillation.</AbstractText> |
13,714 | Automated vulnerability testing identifies patients with inadequate defibrillation safety margin. | Implantable cardioverter-defibrillator system efficacy is tested at implant by induction of ventricular fibrillation (VF). Defibrillation safety margin can be assessed without VF induction using upper limit of vulnerability methods, but these methods have required manual determination of T-wave timing.</AbstractText>To test the feasibility of an inductionless system of implant testing, a multicenter prospective study of an automated vulnerability safety margin system was conducted, which measured T-wave timing using an intracardiac electrogram during a ventricular pacing train. The system delivered up to 4 T-wave shocks of 18 J. Lack of VF induction by all 4 shocks was considered evidence of defibrillation adequacy. Patients subsequently underwent conventional defibrillation testing to meet a standard implant criterion. The 95% lower CI for defibrillation success at 25 J for noninduced patients was found using Bayesian statistics. Sixty patients were enrolled at 6 centers. Vulnerability testing and defibrillation success results were obtained from 54 patients. Vulnerability testing induced VF in 10 (19%) patients, of whom 2 required system revision. All patients not induced by vulnerability testing were successfully defibrillated twice at ≤25 J. The Bayesian credible interval was 97% to 100% for the population success rate of defibrillation at 25 J for automated vulnerability safety margin noninduced patients.</AbstractText>An automated system identified all patients who failed conventional safety margin testing, while inducing only 19% of patients. Although limited by sample size, this study suggests the feasibility of automated implant testing that substantially reduces the need for VF induction in patients receiving implantable cardioverter-defibrillators.</AbstractText> |
13,715 | Mortality and morbidity in cardiac resynchronization patients: impact of lead position, paced left ventricular QRS morphology and other characteristics on long-term outcome. | To investigate the effect of implantation-related characteristics, especially lead position and left ventricular (LV)-paced QRS morphology, on long-term mortality and morbidity in cardiac resynchronization therapy (CRT) patients.</AbstractText>The study retrospectively analysed 362 consecutive patients who underwent CRT device implantation over a 6 year period. Pre-implantation, LV-only paced, and biventricularly paced 12-lead electrocardiograms were obtained. Left ventricular and right ventricular (RV) lead positions were determined using biplane fluoroscopy and roentgenograms. The Kaplan-Meier method was used to estimate the survival function for all-cause death/hospitalization and cardiovascular death/hospitalization. Univariate and multivariate Cox proportional hazards models were also applied. The mean follow-up time was 24.7 ± 16.9 months. There were 79 deaths (62 cardiovascular) and 99 unplanned hospitalizations (72 cardiovascular). One year and 2 year all-cause mortality rates were 8.5 and 18.0%, respectively. Electrocardiographic and fluoroscopic descriptors of the LV lead position were found to be predictors of mortality/morbidity (as were functional class, heart failure aetiology, hyponatremia, and chronic atrial fibrillation). In particular, the antero-apical pattern of LV-only paced QRS showed a hazard ratio (HR) of 1.8 in univariate and 1.7 in multivariate analysis for predicting all-cause death/hospitalization (P = 0.006). The apical/paraseptal LV lead position showed an HR of 2.1 in univariate and 1.9 in multivariate analysis for predicting cardiovascular death/hospitalization (P = 0.018).</AbstractText>To achieve better long-term outcomes in CRT patients the antero-apical pattern of LV QRS complexes and apical or paraseptal LV lead position should be avoided.</AbstractText> |
13,716 | Atrial fibrillation following autologous stem cell transplantation in patients with multiple myeloma: incidence and risk factors. | Atrial fibrillation (AF) often develops in patients with multiple myeloma following autologous stem cell transplantation (ASCT), but the exact incidence of, and the risk factors for AF have not been described. In this study, we sought to determine the incidence of AF in patients with multiple myeloma undergoing ASCT.</AbstractText>Patients who received ASCT for multiple myeloma between January 2000 and December 2009 were identified using the ICD-9 codes for multiple myeloma and ASCT, and formed the basis of this report.</AbstractText>The study included 278 patients (mean age, 63 ± 9.5 years). A total of 75 (27%) patients developed AF at a mean duration of 14.8 days following ASCT. On multiple regression analysis, baseline renal dysfunction (odds ratio 15.2 [confidence interval 5.08-45.6]), left ventricular systolic dysfunction (9.55 [2.78-32.79]), dilated left atrium on echocardiogram (4.97 [1.8-13.78]), and hypertension (3.6 [1.36-9.52]) were significantly associated with the development of AF after ASCT. The presence of light-chain secretion (0.21 [0.07-0.6]) was associated with a lower incidence of AF. Age, gender, and race were not significantly associated with the development of AF after ASCT.</AbstractText>AF is very frequent in patients with multiple myeloma when they receive ASCT. The presence of abnormal renal function, left ventricular systolic dysfunction, dilated left atrium, or hypertension at baseline identifies patients at high risk of developing AF following ASCT.</AbstractText> |
13,717 | Serum and dietary magnesium and incidence of atrial fibrillation in whites and in African Americans--Atherosclerosis Risk in Communities (ARIC) study. | Low serum magnesium (Mg) has been associated with an increased risk of cardiovascular disease (CVD), including ventricular arrhythmias, but the association between serum or dietary Mg and atrial fibrillation (AF) has not been investigated.</AbstractText>A total of 14,290 men and women (75% white; 53% female; mean age, 54 years) free of AF at baseline participating in the Atherosclerosis Risk in Communities study in the United States, were studied. Incident AF cases through 2009 were ascertained from electrocardiograms, hospital discharge codes, and death certificates. Multivariate Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for AF associated with serum and dietary Mg quintiles. Over a median follow-up time of 20.6 years, 1,755 incident AF cases were identified. In multivariate models, lower serum Mg was associated with higher AF risk: compared to individuals in the middle quintile (≥ 0.80-0.83 mmol/L), the HR (95% CI) of AF in quintiles 1, 2, 4, and 5 were 1.34 (1.16-1.54), 0.99 (0.85-1.16), 1.04 (0.90-1.22), and 1.06 (0.91-1.23), respectively. There was no evidence of significant interactions between serum Mg and sex or race. No association between dietary Mg and AF risk was observed.</AbstractText>Lower serum Mg was associated with a higher AF risk, and this association was not different between whites and African Americans. Dietary Mg was not associated with AF risk.</AbstractText> |
13,718 | Obstructive sleep apnea and hypertrophic cardiomyopathy: a common and potential harmful combination. | Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiac disease and is characterized by large and asymmetric septal and left ventricle hypertrophy. HCM is a cause of disability, including heart failure, atrial fibrillation, and sudden death, with an annual mortality varying from 1% to 6%. Obstructive sleep apnea (OSA) is extremely common among patients with established cardiovascular disease, including hypertension and atrial fibrillation and when present may contribute to worse cardiovascular outcome. Although patients with HCM do not necessarily have typical characteristics of patients with OSA, such as obesity and increasing age, there is recent evidence that OSA is extremely common among patients with HCM, with a prevalence ranging from 32% to 71%. The presence of OSA among patients with HCM is independently associated with worse structural and functional impairment of the heart, including atrial and aorta enlargement, worse New York Heart Association functional class, and worse quality of life. The prevalence of atria fibrillation, an independent marker of mortality among patients with HCM, is significantly higher (∼four times) in the presence of OSA. Therefore, the recognition of OSA is a new area of research that may impact the management of patients with HCM. |
13,719 | Effect of ranolazine on ventricular repolarization in class III antiarrhythmic drug-treated rabbits. | Ranolazine exhibits a synergistic effect in combination with class III drugs to suppress atrial fibrillation.</AbstractText>To investigate whether a combination therapy affects repolarization and provokes ventricular tachyarrhythmias (VT) in a sensitive model of proarrhythmia.</AbstractText>Thirty-seven rabbits were assigned to 3 groups and fed with amiodarone (50 mg/kg/d; n = 10) or dronedarone (50 mg/kg/d; n = 10) over a period of 6 weeks. A third group was used as control (n = 17). After obtaining baseline data in Langendorff-perfused control hearts, sotalol (100 μM) was administered in this group. Thereafter, ranolazine (10 μM) was additionally infused on top of amiodarone, dronedarone, or sotalol.</AbstractText>Chronic treatment with amiodarone or dronedarone as well as sotalol significantly increased action potential duration at 90% repolarization (APD(90)). Additional treatment with ranolazine further increased APD(90) in amiodarone- and dronedarone-pretreated hearts but not in sotalol-treated hearts. Ranolazine increased postrepolarization refractoriness as compared with amiodarone or dronedarone alone owing to a marked effect on the refractory period. In contrast to amiodarone and dronedarone, acute application of sotalol increased dispersion of repolarization (P < .05). Additional treatment with ranolazine did not further increase spatial or temporal dispersion. After lowering extracellular [K(+)] in bradycardic hearts, no proarrhythmia occurred in amiodarone- or dronedarone-treated hearts whereas 11 of 17 sotalol-treated hearts showed early afterdepolarizations and subsequent polymorphic VT. Additional treatment with ranolazine reduced the number of VT episodes in sotalol-treated hearts and did not cause proarrhythmia in combination with amiodarone or dronedarone.</AbstractText>Application of ranolazine on top of class III drugs does not cause proarrhythmia despite a marked effect on ventricular repolarization. The effect of ranolazine on the repolarization reserve is associated with the lack of effect on early afterdepolarizations and dispersion of repolarization.</AbstractText>Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,720 | Sevoflurane postconditioning alleviates action potential duration shortening and L-type calcium current suppression induced by ischemia/reperfusion injury in rat epicardial myocytes. | It has been proved that sevoflurane postconditioning (SpostC) could protect the heart against myocardial ischemia/reperfusion injury, however, there has been few research focused on the electrophysiological effects of SpostC. The objective of the study was to investigate the effects of SpostC on action potential duration (APD) and L-type calcium current (I(Ca, L)) in isolated cardiomyocytes.</AbstractText>Langendorff perfused SD rat hearts were randomly assigned to one of the time control (TC), ischemia/reperfusion (I/R, 25 minutes of ischemia followed by 30 minutes of reperfusion), and SpostC (postconditioned with 3% sevoflurane) groups. At the end of reperfusion, epicardial myocytes were dissociated enzymatically for patch clamp studies.</AbstractText>Sevoflurane directly prolonged APD and decreased peak I(Ca, L) densities in epicardial myocytes of the TC group (P < 0.05). I/R injury shortened APD and decreased peak I(Ca, L) densities in epicardial myocytes of the I/R group (P < 0.05). SpostC prolonged APD and increased peak I(Ca, L) densities in epicardial myocytes exposed to I/R injury (P < 0.05). SpostC decreased intracellular reactive oxygen species (ROS) levels, reduced the incidence of ventricular tachycardia and ventricular fibrillation, and decreased reperfusion arrhythmia scores compared with the I/R group (all P < 0.05).</AbstractText>SpostC attenuates APD shortening and I(Ca, L) suppression induced by I/R injury. The regulation of APD and I(Ca, L) by SpostC might be related with intracellular ROS modulation, which contributes to the alleviation of reperfusion ventricular arrhythmia.</AbstractText> |
13,721 | Efficacy of catheter ablation of atrial fibrillation beyond HATCH score. | HATCH score is an established predictor of progression from paroxysmal to persistent atrial fibrillation (AF). The purpose of this study was to determine if HATCH score could predict recurrence after catheter ablation of AF.</AbstractText>The data of 488 consecutive paroxysmal AF patients who underwent an index circumferential pulmonary veins (PV) ablation were retrospectively analyzed. Of these patients, 250 (51.2%) patients had HATCH score = 0, 185 (37.9%) patients had HATCH score = 1, and 53 (10.9%) patients had HATCH score ≥ 2 (28 patients had HATCH score = 2, 23 patients had HATCH score = 3, and 2 patients had HATCH score = 4).</AbstractText>The patients with HATCH score ≥ 2 had significantly larger left atrium size, the largest left ventricular end systolic diameter, and the lowest ejection fraction. After a mean follow-up of (823 ± 532) days, the recurrence rates were 36.4%, 37.8% and 28.3% from the HATCH score = 0, HATCH score = 1 to HATCH score ≥ 2 categories (P = 0.498). Univariate analysis revealed that left atrium size, body mass index, and failure of PV isolation were predictors of AF recurrence. After adjustment for body mass index, left atrial size and PV isolation, the HATCH score was not an independent predictor of recurrence (HR = 0.92, 95% confidence interval = 0.76 - 1.12, P = 0.406) in multivariate analysis.</AbstractText>HATCH score has no value in prediction of AF recurrence after catheter ablation.</AbstractText> |
13,722 | Home monitoring system improves the detection of ventricular arrhythmia and inappropriate shock. | The impact of home monitoring system in the early detection of ventricular arrhythmia and inappropriate shock in daily work is not clear. The aim of this study was to investigate the impact of home monitoring system on the early detection of ventricular arrhythmia and inappropriate shock in daily clinical practice.</AbstractText>Cases of implantable cardioverter defibrillator (ICD) implantation with or without the home monitoring system from June 2010 to October 2011 at our center were reviewed. Follow-up was scheduled after implantation. Data relating to the home monitoring ICD were retrieved using a remote transmitter system. Data relating to the other devices were obtained during scheduled follow-up or unscheduled visits.</AbstractText>Our study involved 69 patients (mean age (68.4 ± 17.6) years, 64.3% males, 26 in the home monitoring group vs. 43 in the non-home monitoring group). In all, 561 ventricular arrhythmia episodes were detected in 17 patients (39.5%) in the non-home monitoring group: 495 episodes were ventricular tachycardia and 66 episodes were ventricular fibrillation; among these, 476 episodes of ventricular tachycardia and 45 episodes of ventricular fibrillation were appropriately diagnosed (96.1% and 68.2%, respectively). In the home monitoring group, 389 ventricular arrhythmia episodes were transmitted by the home monitoring system in nine patients (34.6%): 348 ventricular tachycardia episodes and 41 ventricular fibrillation episodes. Device detection was appropriate in 348 ventricular tachycardia episodes (100.0%) and 36 ventricular fibrillation episodes (87.8%). The home monitoring group showed a higher appropriate detection rate of ventricular tachycardia (P < 0.01) and ventricular fibrillation (P = 0.02). The proportion of inappropriate shock was comparable in the two groups (6/11 in the non-home monitoring group vs. 1/7 in the home monitoring group; P = 0.08).</AbstractText>The home monitoring ICD was able to provide information relating to inappropriate detection and shock earlier than conventional devices. It proved to be a reliable tool and has a strong potential to provide greater reaction time in the case of inappropriate shock.</AbstractText> |
13,723 | Endurance exercise training normalizes repolarization and calcium-handling abnormalities, preventing ventricular fibrillation in a model of sudden cardiac death. | The risk of sudden cardiac death is increased following myocardial infarction. Exercise training reduces arrhythmia susceptibility, but the mechanism is unknown. We used a canine model of sudden cardiac death (healed infarction, with ventricular tachyarrhythmias induced by an exercise plus ischemia test, VF+); we previously reported that endurance exercise training was antiarrhythmic in this model (Billman GE. Am J Physiol Heart Circ Physiol 297: H1171-H1193, 2009). A total of 41 VF+ animals were studied, after random assignment to 10 wk of endurance exercise training (EET; n = 21) or a matched sedentary period (n = 20). Following (>1 wk) the final attempted arrhythmia induction, isolated myocytes were used to test the hypotheses that the endurance exercise-induced antiarrhythmic effects resulted from normalization of cellular electrophysiology and/or normalization of calcium handling. EET prevented VF and shortened in vivo repolarization (P < 0.05). EET normalized action potential duration and variability compared with the sedentary group. EET resulted in a further decrement in transient outward current compared with the sedentary VF+ group (P < 0.05). Sedentary VF+ dogs had a significant reduction in repolarizing K(+) current, which was restored by exercise training (P < 0.05). Compared with controls, myocytes from the sedentary VF+ group displayed calcium alternans, increased calcium spark frequency, and increased phosphorylation of S2814 on ryanodine receptor 2. These abnormalities in intracellular calcium handling were attenuated by exercise training (P < 0.05). Exercise training prevented ischemically induced VF, in association with a combination of beneficial effects on cellular electrophysiology and calcium handling. |
13,724 | Ventricular tachycardia/fibrillation early after defibrillator implantation in patients with hypertrophic cardiomyopathy is explained by a high-risk subgroup of patients. | Implantable cardioverter-defibrillator (ICD) studies in patients with coronary artery disease report higher risk of ventricular tachycardia/fibrillation (VT/VF) early post-implant, potentially related to local proarrhythmic effects of ICD leads.</AbstractText>To characterize early and long-term risk of ICD discharge for VT/VF in a large hypertrophic cardiomyopathy (HCM) cohort.</AbstractText>By using HCM multicenter registry data, we compared long-term risk of VT/VF subsequent to an early post-implant period (a priori defined as within 3 months of implant) between patients with or without VT/VF within 3 months after ICD implantation.</AbstractText>Over a median follow-up of 4.3 years, 109 of 506 (22%) patients with HCM who received ICDs received at least 1 ICD discharge for VT/VF. Risk of first ICD discharge for VT/VF was highest in the first year post-implant (10.8% per person-year; 95% confidence interval 7.9-13.8) and particularly in the first 3 months (17.0% per person-year; 95% confidence interval 9.8-24.3). Patients with early VT/VF (≤3 months post-implant) were older, and more commonly had secondary prevention ICDs following cardiac arrest or systolic dysfunction (end-stage HCM with ejection fraction<50%). Only 2 of 247 (0.7%) patients with primary prevention ICDs and preserved systolic function had early VT/VF. Patients with VT/VF early post-implant (≤3 months) had more than 5-fold higher risk for future VT/VF during long-term follow-up compared with patients without early VT/VF (adjusted hazard ratio 5.4; 95% confidence interval 2.3-12.6).</AbstractText>High-risk patients with HCM and VT/VF early after ICD implantation are particularly prone to subsequent VT/VF throughout follow-up. Early ICD interventions for VT/VF are largely confined to patients with prior cardiac arrest or systolic dysfunction and therefore more likely driven by higher arrhythmic risk rather than lead-related proarrhythmia.</AbstractText>Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,725 | Gender-related differences in patients with acute heart failure: management and predictors of in-hospital mortality. | Gender-related differences in clinical phenotype, in-hospital management and prognosis of acute heart failure (AHF) patients have been previously reported in European and US registries. The ALARM-HF survey is the first to include a cohort of 4953 patients hospitalized for AHF in 666 hospitals in 6 European countries, Mexico and Australia.</AbstractText>Women accounted for 37% of the study population, were older and had higher rates of de novo heart failure (45% vs 36%, p<0.001) than men. An acute coronary syndrome (ACS) was the predominant precipitating factor in both genders, but to a lesser extent in females (30% vs 42%, p<0.001). Between genders comparison showed higher incidence of atrial fibrillation, valvular heart disease, diabetes, obesity, anemia and depression in women (p<0.05). Similarly, women had higher left ventricular ejection fraction (LVEF) on admission (42 ± 15% vs 36 ± 13%, p<0.001) and systolic blood pressure (135 ± 40 mm Hg vs 131 ± 39 mm Hg, p=0.001) than men. On the other hand, men had more often coronary artery disease, renal failure and chronic obstructive pulmonary disease (p<0.05). Importantly, in-hospital mortality was similar in both genders (11.1% in females vs 10.5% in males, p=0.475), and its common predictors were: systolic blood pressure at admission, creatinine>1.5mg/dL and diabetes. Furthermore, recent ACS, valvular heart disease and dementia contributed to prognosis in women, while LVEF, hypertension and anemia were independent predictors in men.</AbstractText>Among patients with AHF, there are significant differences in co-morbidities, precipitating factors and predictors of in-hospital mortality between genders. Nevertheless, in-hospital mortality remains similar between genders.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,726 | Effects of ganglionated plexi ablation on ventricular electrophysiological properties in normal hearts and after acute myocardial ischemia. | Ganglionated plexi (GP) ablation has been shown to play an important role in atrial fibrillation (AF) initiation and maintenance. Also, GP ablation increases chances for prevention of AF recurrence. This study investigated the effects of GP ablation on ventricular electrophysiological properties in normal dog hearts and after acute myocardial ischemia (AMI).</AbstractText>Fifty anesthetized dogs were assigned into normal heart group (n=16) and AMI heart group (n=34). Ventricular dynamic restitution, effective refractory period (ERP), electrical alternans and ventricular fibrillation threshold (VFT) were measured before and after GP ablation in the normal heart group. In the AMI heart group, the incidence of ventricular arrhythmias and VFT were determined.</AbstractText>In the normal heart group, GP ablation significantly prolonged ERP, facilitated electrical alternans but did not increase ERP dispersion, the slope of restitution curves and its spatial dispersion. Also, GP ablation did not cause significant change of VFT. In the AMI heart group, the incidence of ventricular arrhythmias after GP ablation was significantly higher than that in the control group or the GP plus stellate ganglion (SG) ablation group (P<0.05). Spontaneous VF occurred in 8/12, 1/10 and 2/12 dogs in the GP ablation group, the GP plus SG ablation group and the control group, respectively (P<0.05). VFT in the GP ablation group showed a decreased trend though a significant difference was not achieved compared with the control or the GP plus SG ablation group.</AbstractText>GP ablation increases the risk of ventricular arrhythmias in the AMI heart compared to the normal heart.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,727 | Development of a method to risk stratify patients with heart failure for 30-day readmission using implantable device diagnostics. | The aim of the present study was to evaluate whether diagnostic data collected after a heart failure (HF) hospitalization can identify patients with HF at risk of early readmission. The diagnostic data from cardiac resynchronization therapy defibrillator (CRT-D) devices can identify outpatient HF patients at risk of future HF events. In the present retrospective analysis of 4 studies, we identified patients with CRT-D devices, with a HF admission, and 30-day postdischarge follow-up data. The evaluation of the diagnostic data for impedance, atrial fibrillation, ventricular heart rate during atrial fibrillation, loss of CRT-D pacing, night heart rate, and heart rate variability was modeled to simulate a review of the first 7 days after discharge on the seventh day. Using a combined score created from the device parameters that were significant univariate predictors of 30-day HF readmission, 3 risk groups were created. A Cox proportional hazards model adjusting for age, gender, New York Heart Association class, and length of stay during the index hospitalization was used to compare the groups. The study cohort of 166 patients experienced a total of 254 HF hospitalizations, with 34 readmissions within 30 days. Daily impedance, high atrial fibrillation burden with poor rate control (>90 beat/min) or reduced CRT-D pacing (<90% pacing), and night heart rate >80 beats/min were significant univariate predictors of 30-day HF readmission. Patients in the "high"-risk group for the combined diagnostic had a significantly greater risk (hazard ratio 25.4, 95% confidence interval 3.6 to 179.0, p = 0.001) compared to the "low"-risk group for 30-day readmission for HF. In conclusion, device-derived HF diagnostic criteria evaluated 7 days after discharge identified patients at significantly greater risk of a HF event within 30 days after discharge. |
13,728 | Genetic variants of the renin-angiotensin-aldosterone system and reverse remodeling after cardiac resynchronization therapy. | Reverse remodeling (RR) after cardiac resynchronization therapy (CRT) is associated with favorable clinical outcomes in heart failure (HF). The renin-angiotensin-aldosterone system (RAAS) is involved in the remodeling process.</AbstractText>We assessed the association between RR and 8 common RAAS gene variants, which were determined by TaqMan assays, in 156 outpatients with chronic HF. RR was defined as a >15% decrease in left ventricular end systolic volume (LVESV) at 9 (interquartile range 7-12) months after CRT. We matched 76 patients who did not show RR (RR-) to 80 RR+ control subjects by age, sex, HF etiology, New York Heart Association (NYHA) functional class and left ventricular ejection fraction (LVEF). The frequency of the minor allele of the NR3C2 gene (rs5522 C/T), encoding the mineralocorticoid receptor, was higher in RR- than in RR (24/126 vs 10/150; P value after false discovery rate correction: <.0193). Conversely, LVESV decreased significantly less after CRT in carriers of the NR3C2 minor C allele (P = .02). After adjustment for age, sex, NYHA functional class, previous myocardial infarction, atrial fibrillation, and LVEF, RR- remained independently associated with NR3C2 C allele carriage (odds ratio 3.093, 95% confidence interval 1.253-7.632).</AbstractText>The association of RR- after CRT with a common polymorphism in the mineralocorticoid receptor gene involved in aldosterone signaling suggests a possible role for variants in RAAS genes in progressive LV function decline, despite apparently effective CRT.</AbstractText>Copyright © 2012 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,729 | Abnormal Left Ventricular Filling and Postoperative Atrial Fibrillation After Cardiac Surgery. | <b>Objective:</b> Diastolic dysfunction has been associated with the development of atrial fibrillation (AF) in the community and recently in the postoperative setting. We hypothesized that abnormal left ventricular filling predicts AF after cardiac surgery, a common marker of poor outcomes. <b>Methods:</b> Cohort study of 233 consecutive patients, who underwent coronary artery bypass grafting (CABG) and/or valve surgery. Early and late mitral inflow velocity (E, A) and deceleration time (DT) and early mitral annular velocity (e?) were obtained from echo within 6 months prior to cardiac surgery. Associations with postoperative AF were studied with multivariable logistic regression. <b>Results:</b> Postoperative AF occurred in 65 (28%) of patients, who were on average older, more likely to have had prior episodes of AF, had larger inferior vena cava diameter and shorter DT (189 ± 62ms vs. 214 ± 63ms, p=0.007). Multivariable adjusted analyses demonstrated only DT (odds ratio [OR] 0.65 (95% confidence interval [CI] 0.40-0.97), older age (OR 2.62 (95% CI 1.68 - 4.10) and prior episodes of atrial fibrillation (OR 7.20, CI 1.41-36.8) to be independent predictors of postoperative AF. Patients with a DT ≤ 200ms (n=117) had a significantly longer length of hospital stay compared with those who had DT > 200ms (n=116) (median 7 days (interquartile range [IQR] 5-10) vs. 6 days (IQR 5-7, p=0.0002). <b>Conclusion:</b> In patients who undergo cardiac surgery, a shorter DT of early mitral inflow identified greater risk for postoperative AF and a longer hospital stay. These results provide useful information for preoperative risk assessment and mechanistic understanding of postoperative AF. |
13,730 | Impact of Atrial Fibrillation on Coronary Blood Flow: A Systematic Review. | Patients with atrial fibrillation (AF) frequently present with symptoms suggestive of myocardial isch- aemia, even in the absence of significant CAD, that seem to be attributable to abnormalities of myocardial perfusion and perfusion reserve. According to the results of recent human and previous experimen- tal studies the increase in coronary artery blood flow during AF is smaller, while the coronary vascular resistance during the arrhythmia does not decrease as much as we would expect, suggesting a mismatch between coronary blood flow and myocardial metabolic demand. AF itself diminishes coronary flow reserve, especially in the subendocardial layer, partly as a result of the increase in the myocardial com- ponent of coronary vascular resistance, and it is possible that irregular ventricular rhythm may play an important role. The mismatch of coronary blood flow and myocardial metabolic demand, especially in view of the severe reduction in coronary flow reserve, may have deleterious consequences that are not limited to patients with CAD. |
13,731 | Acute myocardial infarction with a left main trunk lesion and documented lambda-like J waves. | We herein describe a case of a myocardial infarction, in which Lambda-like J waves were documented. The patient was referred to our hospital due to ventricular fibrillation. The twelve-lead electrocardiogram (ECG) on admission showed prominent J waves in the lateral and precordial leads. Coronary angiography revealed 99% stenosis with a delay in the left anterior descending artery, 75% stenosis in the left main trunk, and possible ischemia in the conus branch. Our report addresses the possibility that ischemic J waves can be used as an important marker for lethal arrhythmias in patients with acute myocardial infarction. |
13,732 | Use of cardiocerebral resuscitation or AHA/ERC 2005 Guidelines is associated with improved survival from out-of-hospital cardiac arrest: a systematic review and meta-analysis. | To determine whether the use of cardiocerebral resuscitation (CCR) or AHA/ERC 2005 Resuscitation Guidelines improved patient outcomes from out-of-hospital cardiac arrest (OHCA) compared to older guidelines.</AbstractText>Systematic review and meta-analysis.</AbstractText>MEDLINE, EMBASE, Web of Science and the Cochrane Library databases. We also hand-searched study references and consulted experts.</AbstractText>Design: randomised controlled trials and observational studies.</AbstractText>OHCA patients, age >17 years.</AbstractText>'Control' protocol versus 'Study' protocol. 'Control' protocol defined as AHA/ERC 2000 Guidelines for cardiopulmonary resuscitation (CPR). 'Study' protocol defined as AHA/ERC 2005 Guidelines for CPR, or a CCR protocol.</AbstractText>Survival to hospital discharge.</AbstractText>High-quality or medium-quality studies, as measured by the Newcastle Ottawa Scale using predefined categories.</AbstractText>Twelve observational studies met inclusion criteria. All the three studies using CCR demonstrated significantly improved survival compared to use of AHA 2000 Guidelines, as did five of the nine studies using AHA/ERC 2005 Guidelines. Pooled data demonstrate that use of a CCR protocol has an unadjusted OR of 2.26 (95% CI 1.64 to 3.12) for survival to hospital discharge among all cardiac arrest patients. Among witnessed ventricular fibrillation/ventricular tachycardia (VF/VT) patients, CCR increased survival by an OR of 2.98 (95% CI 1.92 to 4.62). Studies using AHA/ERC 2005 Guidelines showed an overall trend towards increased survival, but significant heterogeneity existed among these studies.</AbstractText>We demonstrate an association with improved survival from OHCA when CCR protocols or AHA/ERC 2005 Guidelines are compared to use of older guidelines. In the subgroup of patients with witnessed VF/VT, there was a threefold increase in OHCA survival when CCR was used. CCR appears to be a promising resuscitation protocol for Emergency Medical Services providers in increasing survival from OHCA. Future research will need to be conducted to directly compare AHA/ERC 2010 Guidelines with the CCR approach.</AbstractText> |
13,733 | Nationwide improvements in survival from out-of-hospital cardiac arrest in Japan. | Little is known about the nationwide trend in the survival of out-of-hospital cardiac arrest (OHCA) in Japan and the differences in incidence and survival by age group and origin of arrest.</AbstractText>A nationwide, prospective, population-based observation covering the whole population of Japan and involving consecutive OHCA patients with resuscitation attempts was conducted from January 2005 to December 2009. The main outcome measure was 1-month survival with favorable neurological outcome. The nationwide trends in OHCA incidence and outcome by age and origin of arrest were assessed. Multiple logistic regression analysis for bystander-witnessed OHCA was used to adjust for factors that were potentially associated with favorable neurological outcome. During 5 years, 547 153 overall OHCAs and 169 360 bystander-witnessed OHCAs were enrolled. The annual incidence significantly increased among overall OHCAs and bystander-witnessed OHCAs. Neurologically favorable survival significantly increased from 1.6% (1676/102 737) in 2005 to 2.8% (3280/115 250) in 2009 (P<0.001), from 2.1% (638/30 556) to 4.3% (1558/36 361) (P<0.001), and from 9.8% (437/4461) to 20.6% (1215/5906) (P<0.001) among overall OHCA, bystander-witnessed OHCA, and bystander-witnessed ventricular fibrillation OHCA, respectively. Public-access automated external defibrillator use, either bystander-initiated chest compression-only cardiopulmonary resuscitation or conventional cardiopulmonary resuscitation, and earlier emergency medical services response time were associated with a better neurological outcome. Favorable neurological outcome among adult OHCA subjects significantly improved, but the outcome among younger children and very elderly subjects did not improve and was poor irrespective of origin of OHCA.</AbstractText>Nationwide improvements of favorable neurological outcome from OHCA were observed in Japan and differed by age group and origin of OHCA.</AbstractText> |
13,734 | Implantation and follow-up of totally subcutaneous versus conventional implantable cardioverter-defibrillators: a multicenter case-control study. | The approval of an entirely subcutaneous implantable-cardioverter defibrillator (ICD) system (S-ICD) has raised attention about this promising technology. It was developed to overcome lead failure and infection problems of conventional transvenous ICD systems. Nevertheless, lead migration of the initial design and inappropriate shock rates have raised concerns regarding its reliability and safety.</AbstractText>The purpose of this study was to report the largest multicenter series to date of patients with the new device in comparison with a matched conventional transvenous ICD collective with focus on perioperative complications, conversion of induced ventricular fibrillation (VF), and short-term follow-up.</AbstractText><AbstractText Label="METHODS/RESULTS" NlmCategory="RESULTS">Sixty-nine patients (50 male and 19 female; mean age 45.7 ± 15.7 years) received an S-ICD in three German centers and were randomly assigned to 69 sex- and age-matched conventional ICD patients. The indication was primary prevention in 41 patients (59.4%) without difference between groups (34 control patients; P = .268). The predominant underlying heart disease was ischemic cardiomyopathy in 11 (15.9%), dilated cardiomyopathy in 25 (36.2%), and hypertrophic cardiomyopathy in 10 (14.5%) in the S-ICD group. Mean implantation time was 70.8 ± 27.9 minutes (P = .398). Conversion rates of induced VF were 89.5% for 65 J (15-J safety margin) and 95.5% including reversed shock polarity (15-J safety margin) in the study group. Termination of induced VF was successful in 90.8% (10-J safety margin, device dependent) of the control patients (P = .815). Procedural complications were similar between the 2 groups. Mean follow-up was 217 ± 138 days. During follow-up, 3 patients with S-ICD were appropriately treated for ventricular arrhythmias. Three inappropriate episodes (5.2%) occurred in 3 S-ICD patients due to T-wave oversensing, whereas atrial fibrillation with rapid conduction was the predominant reason for inappropriate therapy in conventional devices (P = .745).</AbstractText>The novel S-ICD system can be implanted safely with similar perioperative adverse events compared with standard transvenous devices. Our case-control study demonstrates a 10.4% failure of conversion of induced VF with the S-ICD set to standard polarity and 15-J safety margin and comparable inappropriate shock rates during short-term follow-up.</AbstractText>Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,735 | Current is better than energy as predictor of success for biphasic defibrillatory shocks in a porcine model of ventricular fibrillation. | The evidence that monophasic defibrillation success is mainly determined by current is secure. However, modern defibrillators use biphasic waveforms. The aim of this study was to compare energy, peak voltage and peak current in predicting biphasic shock success in a porcine model of ventricular fibrillation (VF) where the impedance varies within a wide of ranges.</AbstractText>In 14 domestic male pigs weighing between 27 and 38 kg, VF was electrically induced and untreated for 15 s. Animals were randomized to receive defibrillation attempts from one of two defibrillators with different impedance compensation methods. A grouped up-and-down defibrillation threshold testing protocol was used to maintain the average success rate in the neighborhood of 50%. After a recovery interval of 5 min, the testing sequence was repeated for a total of 60 test shocks for each animal.</AbstractText>A high defibrillation success was observed when high peak current was delivered. The area under ROC curve for predicting shock success was 0.681 for peak current, 0.585 for peak voltage and 0.562 for energy. The odds ratio revealed that peak current was a better predictor (OR=1.321, p<0.001) for defibrillation outcome compared with energy (OR=0.979, p<0.001) and peak voltage (OR=1.000, p=0.69) when multivariable logistic regression was conducted.</AbstractText>In this porcine model of VF within a wide range of transthoracic impedance, peak current was a better indicator for shock success than the currently used energy for biphasic defibrillatory shocks. This finding may encourage design of new current-based biphasic defibrillators.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,736 | ECG manifestations in acute organophosphorus poisoning. | A cross-sectional study was conducted to evaluate the electrocardiographic changes in 107 patients of acute organophosphorus poisoning admitted at casuality ward of MGM Medical College, Kisanganj from June 2007 to June 2010. Electrocardiographic changes were recorded before the administration of atropine. Prolonged Q-Tc interval was the commonest ECG abnormality, found in 67 patients (62.6%), followed by sinus tachycardia in 36 patients (33.6%). Sinus bradycardia was found in 33 patients (30.8%). Elevation of ST segment was seen in 27 patients (25.2%). T wave inversion was seen in 21 patients (19.6%). First-degree heart block (P-R interval >0.20 seconds) occurred in 9 cases (8.4%). Atrial fibrillation was seen in 5 patients (4.6%). Ventricular tachycardia was seen in 6 cases (5.6%) and ventricular premature complexes in 3 patients (2.8%). Of these 6 cases of ventricular tachycardia 1 responded to intravenous lignocaine, and the other 5 developed ventricular fibrillation leading to death despite other resuscitative measures. All the electrocardiographical abnormalities returned to normal before the patients were discharged. Seventeen patients died. The cause of death was ventricular fibrillation in 5 patients and non-cardiogenic pulmonary oedema in others. In conclusion it can be said that ECG should be carefully recorded and analysed in all patients of acute organophosphorus poisoning, and depending upon these changes and other clinical and biochemical parameters, the patients should immediately be shifted to well equipped ICU for better care which will reduce the mortality rate caused by these highly lethal poisons. |
13,737 | Different types of long-duration ventricular fibrillation: can they be identified by electrocardiography. | We tested the hypothesis that after 2 minutes of ventricular fibrillation (VF), periods of highly organized activations occur on the endocardium, arising from an intramural mother rotor or triggered activity originating in the Purkinje fibers. In 6 anesthetized dogs, we recorded electrically induced VF from two-thirds of the endocardium with a 64-electrode basket catheter. In another 12 dogs, the study was repeated with the addition of the early afterdepolarization blocker pinacidil in 6 animals and the delayed afterdepolarization blocker flunarizine in the other 6 animals. We found that, in addition to periods of disorganized chaotic activation (type I pattern), at between 3 and 7 minutes of VF, 2 highly organized patterns were observed (type II pattern, regular activity and type III pattern, triggered activity). When present, these patterns were observed in all 64 electrodes simultaneously. Type II arises from the apex and may be an intramural mother rotor and type III arises focally in Purkinje fibers and may be caused by early afterdepolarizations. The optimal defibrillation strategy may be different for the 3 different VF patterns. Therefore, it is important to determine if these 3 patterns can be differentiated from the body surface electrocardiogram. |
13,738 | Defibrillation threshold varies during different stages of ventricular fibrillation in canine hearts. | Recent studies have shown that short duration ventricular fibrillation (SDVF) and long duration ventricular fibrillation (LDVF) are maintained by different mechanisms. The objective of this study is to evaluate how the defibrillation threshold (DFT) varies over the duration of fibrillation since the mechanism of VF maintenance changes as VF progresses.</AbstractText>Twelve canines were randomly divided into two groups (Group A and B, n=6 each). DFTs were measured three times in each group: SDVF (20s), LDVF (3min in Group A and 7min in Group B) and the first episode of refibrillation after successful defibrillation for LDVF. Two 64-electrode baskets used to globally map the endocardium were deployed into the left ventricle and right ventricle, respectively.</AbstractText>LDVF-DFT in Group A was significantly higher than that of Group B (628±98V vs 313±81V, P<0.001). In Group B, the DFT of refibrillation was significantly increased compared with the LDVF-DFT (570±199V vs 313±81V, P=0.035) but did not differ from the DFT of refibrillation in Group A (570±199V vs 638±116V, P=0.39). Highly synchronised activation patterns on the left ventricular endocardium were observed between 3 and 7min of LDVF in Group B but not within 3min-LDVF in Group A or during refibrillation in each group.</AbstractText>DFT varied during different stages of VF. The highly synchronised activation patterns exhibiting after 3min VF might contribute to the decreased LDVF-DFT.</AbstractText>Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.</CopyrightInformation> |
13,739 | [Totally subcutaneous defibrillator]. | The implantable cardioverter-defibrillators (ICD) is a therapy for the prevention of sudden cardiac death. Complications with implant have been associated mainly with transvenous lead insertion. Difficulties in achieving venous access can occasionally result in failed ICD implantation. Lead failures remains a major limitation and often require removal. This procedure is associated with important morbidity and mortality. To eliminate the need for venous access, Bardy et al. designed an entirely subcutaneous ICD system. The subcutaneous ICD consists of a 3-mm tripolar parasternal electrode positioned parallel to the left of the sternal midline and guided exclusively by anatomical landmarks without fluoroscopy. The pulse generator is positioned over the sixth rib between the midaxillary line and the anterior axillary line. The device delivers a maximum of only 80-J shocks. Ventricular fibrillation was converted twice in 58 of 59 patients (98%) with the delivery of 65-J shocks in two tests to ensure a margin of safety. A demand pacing at 50 beats per minute is available for 30 seconds after a shock. These studies are preliminary but the system will need to be employ in a long-term, randomized, prospective, multicenter clinical trials. |
13,740 | Prediction of mortality in clinical practice for medicare patients undergoing defibrillator implantation for primary prevention of sudden cardiac death. | The aim of this study was to derive and validate a practical risk model to predict death within 4 years of primary prevention implantable cardioverter-defibrillator (ICD) implantation.</AbstractText>ICDs for the primary prevention of sudden cardiac death improve survival, but recent data suggest that a patient subset with high mortality and minimal ICD benefit may be identified.</AbstractText>Data from a development cohort (n = 17,991) and validation cohort (n = 27,893) of Medicare beneficiaries receiving primary prevention ICDs from 2005 to 2007 were merged with outcomes data through mid-2010 to construct and validate complete and abbreviated risk models for all-cause mortality using Cox proportional hazards regression.</AbstractText>Over a median follow-up period of 4 years, 6,741 (37.5%) development and 8,595 (30.8%) validation cohort patients died. The abbreviated model was based on 7 clinically relevant predictors of mortality identified from complete model results, referred to as the "SHOCKED" predictors: 75 years of age or older (hazard ratio [HR]: 1.70; 95% confidence interval [CI]: 1.62 to 1.79), heart failure (New York Heart Association functional class III) (HR: 1.35; 95% CI: 1.29 to 1.42), out of rhythm because of atrial fibrillation (HR: 1.26; 95% CI: 1.19 to 1.33), chronic obstructive pulmonary disease (HR: 1.70; 95% CI: 1.61 to 1.80), kidney disease (chronic) (HR: 2.33; 95% CI: 2.20 to 2.47), ejection fraction (left ventricular) ≤ 20% (HR: 1.26; 95% CI: 1.20 to 1.33), and diabetes mellitus (HR: 1.43; 95% CI: 1.36 to 1.50). This model had C-statistics of 0.75 (95% CI: 0.75 to 0.76) and 0.74 (95% CI: 0.74 to 0.75) in the development and validation cohorts, respectively. Validation patients in the highest risk decile on the basis of the SHOCKED predictors had a 65% 3-year mortality rate. A nomogram is provided for survival probabilities 1 to 4 years after ICD implantation.</AbstractText>This useful model, based on more than 45,000 primary prevention ICD patients, accurately identifies patients at highest risk for death after device implantation and may significantly influence clinical decision making.</AbstractText>Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,741 | Left ventricular midwall fibrosis as a predictor of mortality and morbidity after cardiac resynchronization therapy in patients with nonischemic cardiomyopathy. | The aim of this study was to determine whether left ventricular (LV) midwall fibrosis, detected by midwall hyperenhancement (MWHE) on late gadolinium enhancement cardiovascular magnetic resonance (CMR) imaging, predicts mortality and morbidity in patients with dilated cardiomyopathy (DCM) undergoing cardiac resynchronization therapy (CRT).</AbstractText>Midwall fibrosis predicts mortality and morbidity in patients with DCM.</AbstractText>Patients with DCM with (+) or without (-) MWHE (n = 20 and n = 77, respectively) as well as 161 patients with ischemic cardiomyopathy (ICM) undergoing CRT (n = 258) were followed up for a maximum of 8.7 years.</AbstractText>Among patients with DCM, +MWHE predicted cardiovascular mortality (hazard ratio [HR]: 18.6; 95% confidence intervals [CI]: 3.51 to 98.5; p = 0.0008), total mortality or hospitalization for major adverse cardiovascular events (HR: 7.57; 95% CI: 2.71 to 21.2; p < 0.0001), and cardiovascular mortality or heart failure hospitalizations (HR: 9.56; 95% CI: 2.72 to 33.6; p = 0.0004), independent of New York Heart Association class, QRS duration, atrial fibrillation, LV volumes, LV ejection fraction, and a CMR-derived measure of dyssynchrony. Among patients with DCM and ICM, the risk of cardiovascular mortality for DCM +MWHE (adjusted HR: 18.5; 95% CI: 3.93 to 87.3; p = 0.0002) was similar to that for ICM (adjusted HR: 21.0; 95% CI: 5.06 to 87.2; p < 0.0001). Both DCM +MWHE and ICM were predictors of pump failure death as well as sudden cardiac death. LV reverse remodeling was observed in DCM -MWHE and in ICM but not in DCM +MWHE.</AbstractText>Midwall fibrosis is an independent predictor of mortality and morbidity in patients with DCM undergoing CRT. The outcome of DCM with midwall fibrosis is similar to that of ICM. This relationship is mediated by both pump failure and sudden cardiac death.</AbstractText>Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,742 | Association of KCNE1 genetic polymorphisms with atrial fibrillation in a Chinese Han population. | The purpose of this study was to investigate the association of the polymorphisms of the KCNE1 gene with atrial fibrillation (AF) in a Chinese Han population.</AbstractText>Three hundred seven AF patients and 330 age- and sex-matched controls were genotyped using the polymerase chain reaction-restriction fragment length polymorphism method for two single-nucleotide polymorphisms (rs1805127 and rs1892593) of the human KCNE1 gene.</AbstractText>The frequencies of the AA, AG, and GG genotypes of rs1805127 were 11.7%, 50.0%, and 43.3%, respectively, in the AF group, whereas the ones in the control group had frequencies of 19.4%, 44.9%, and 35.8%, respectively. There were significant differences in frequencies of these three genotypes (χ(2)=7.820, p=0.016) and G allele (65.8% vs. 58.2%; χ(2)=8.266, p=0.005). The frequencies of AA, AG, and GG of rs1892593 were 38.4%, 47.9%, and 13.7% in the AF group, whereas the ones in the control group had frequencies of 37.8%, 48.5%, and 14.0%, respectively. There was no difference in distributions of frequencies of these three genotypes and allele (χ(2)=0.051, p=0.978; χ(2)=1.024, p=0.837, respectively) between AF patients and control subjects. We also found that rs1805127 was associated with left atrial diameter and left ventricular end diastolic diameter in AF patients (χ(2)=24.883, p<0.001; χ(2)=34.901, p<0.001, respectively). Logistic regression analysis showed that rs1805127 was an independent risk factor of AF in a Chinese Han population (odds ratio [OR]=1.66, 95% confidence interval [CI]: 1.02-2.68 for AG; OR=2.03, 95% CI: 1.24-3.31 for GG).</AbstractText>The genetic polymorphism of KCNE1 was associated with increased risk of AF in a Chinese Han population.</AbstractText> |
13,743 | Should we use automated external defibrillators in hospital wards? | Automated external defibrillators (AEDs) have shown to improve survival after cardiopulmonary arrest (CPA) in many, but not all clinical settings. A recent study reported that the use of AEDs in-hospital did not improve survival. The current retrospective study reports the results of an in-hospital AED programme in a university hospital, and focuses on the quality of AED use. At Ghent University Hospital 30 AEDs were placed in non-monitored hospital wards and outpatient clinics treating patients with non-cardiac problems. Nurses were trained to use these devices. From November 2006 until March 2011, the AEDs were used in 23 of 39 CPA cases, in only one patient the presenting heart rhythm was ventricular fibrillation and this patient survived. Pulseless electrical activity was present in 14 patients (four survived) and asystole in eight patients (one survived). AEDs were attached to eight patients without CPA, and in 16 patients with CPA AED was not used. The quality of AED use was often suboptimal as illustrated by external artifacts during the first rhythm analysis by the AED in 30% (7/23) and more than 20 seconds delay before restart of chest compressions after the AED rhythm analysis in 50% (9/18). The literature data, supported by our results, indicate that in-hospital AED programmes are unlikely to improve survival after CPA. Moreover, their use is often suboptimal. Therefore, if AEDs are introduced in a hospital, initial training, frequent retraining and close follow-up are essential. |
13,744 | Permanent left atrial pacing therapy may improve symptoms in heart failure patients with preserved ejection fraction and atrial dyssynchrony: a pilot study prior to a national clinical research programme. | Our group has recently shown that in some patients, heart failure with preserved ejection fraction (HFPEF) may be explained by 'atrial dyssynchrony syndrome' (ADS) due to interatrial conduction delay (IACD), a short left atrioventricular interval (LAVI), and increased left atrial (LA) stiffness. Our primary objective was to evaluate LA pacing therapy as a new treatment to restore left ventricular active filling in patients with no other known causes for HF than ADS.</AbstractText>Six patients with severe HFPEF with IACD (P wave duration >120 ms in lead II), short LAVI during electrophysiological studies (<70 ms), a restrictive filling pattern (E/e' >15), and no standard indication for a pacemaker were implanted with a lead screwed inside the coronary sinus for active LA pacing. After 3 months of active pacing, a 2 week randomized double-blind crossover phase compared active vs. inactive LA pacing. After 3 months of pacing, the mean distance walked in 6 min (6MWD) was 21% greater (240 ± 25 m vs. 190 ± 15m, P < 0.05), mitral A wave duration was longer (104 ± 8 vs. 158 ± 25 ms, P = 0.002), and E/A and E/e' ratios were smaller (3.4 ± 1.3 vs. 1.8 ± 0.9, P = 0.009, and 22.6 ± 4.6 vs. 15.3 ± 4.3, P = 0.006, respectively). Inactivation of pacing for 1 week led to a significant reduction in the 6MWD, with an on/off response.</AbstractText>The beneficial effects of LA pacing observed in this pilot study will have to be confirmed by the randomized, controlled crossover 'LEAD' study.</AbstractText> |
13,745 | Can dexmedetomidine be a safe and efficacious sedative agent in post-cardiac surgery patients? a meta-analysis. | The aim of this study was to explore the use of dexmedetomidine as a safe and efficacious sedative agent in post-cardiac surgery patients.</AbstractText>A systematic literature search of MEDLINE, EMBASE, the Cochrane Library and Science Citation Index until January 2012 and review of studies was conducted. Eligible studies were of randomized controlled trials or cohort studies, comparing dexmedetomidine with a placebo or an alternative sedative agent in elective cardiac surgery, using dexmedetomidine for postoperative sedation and available in full text. Two reviewers independently performed study selection, quality assessment, and data extraction.</AbstractText>The search identified 530 potentially relevant publications; 11 met selection criteria in this meta-analysis. Our results revealed that dexmedetomidine was associated with a shorter length of mechanical ventilation (mean difference -2.70 [-5.05, -0.35]), a lower risk of delirium (risk ratio 0.36 [0.21, 0.64]), ventricular tachycardia (risk ratio 0.27 [0.08, 0.97]) and hyperglycemia (risk ratio 0.78 [0.61, 0.99]), but may increase the risk of bradycardia (risk ratio 2.08 [1.16, 3.74]). But there was no significant difference in ICU stay, hospital stay, and morphine equivalents between the included studies. Dexmedetomidine may not increase the risk of hypotension, atrial fibrillation, postoperative nausea and vomiting, reintubation within 5 days, cardiovascular complications, postoperative infection or hospital mortality.</AbstractText>Dexmedetomidine was associated with shorter length of mechanical ventilation and lower risk of delirium following cardiac surgery. Although the risk of bradycardia was significantly higher compared with traditional sedatives, it may not increase length of hospital stay and hospital mortality. Moreover, dexmedetomidine may decrease the risk of ventricular tachycardia and hyperglycemia. Thus, dexmedetomidine could be a safe and efficacious sedative agent in cardiac surgical patients.</AbstractText> |
13,746 | [Effects and the mechanisms of cardiac short-term memory on cellular electrical excitability]. | Electrical instability easily induces a unidirectional conduction block, resulting in ventricular tachycardia (VT) or even fibrillation (VF). Cardiac memory affects dynamic electrical characteristics through previous pacing so that it makes the memory important in arrhythmia study. This paper investigates the impact of the rapid pacing duration on cellular excitability and its mechanism. Based on the canine endocardial single cell, a one-dimensional tissue model was developed. Simulations were realized with OpenMP parallel programming method. The results showed that with repetitive pacing, the cellular excitability became low while the conduction velocity decreased. Accumulation of intracellular [Ca2+]i and [Na+]i and depletion of [K+]i led to the shift of membrane current-voltage curves, changing the membrane resistance. Excitability determined by the resistance at the large width of stimulus pulse, therefore, it suggested that [Ca2+]i and [K+]i-induced memory formed the ionic substrates for the alteration of excitability. |
13,747 | Realities of biomedical product liability suits and the role of junk science: from breast implants to TASER weapons. | In the summer of 2006, manufacturers of a simple respirator mask costing US$1 told the U.S. Congress that Americans would find a shortage of these masks if there was another flu pandemic. The reason for this was that suing the makers of these dust masks became a major business for trial lawyers. By 2006, there had been more than 326,000 lawsuits filed. It has been reported in many cases that the law firms worked with cooperative physicians and contracted with X-ray labs to screen individuals for lung problems. If an individual had an abnormal lung X-ray and claimed that they had used a certain brand of respirator and the manufacturer was still in business and had economic resourcesa lawsuit was filed. Some manufacturers went out of business while others simply stopped making the masks. |
13,748 | Irregular rhythm adversely influences calcium handling in ventricular myocardium: implications for the interaction between heart failure and atrial fibrillation. | Despite adequate rate control, the combination of atrial fibrillation with heart failure (HF) has been shown, in a number of studies, to hasten HF progression. In this context, we aimed to test the hypothesis that an irregular ventricular rhythm causes an alteration in ventricular cardiomyocyte excitation-contraction coupling which contributes to the progression of HF.</AbstractText>We investigated the effects of electrical field stimulation (average frequency 2 Hz) in an irregular versus regular drive train pattern on the expression of calcium-handling genes and proteins in rat ventricular myocytes. The effect of rhythm on intracellular calcium transients was examined using Fura-2AM fluorescence spectroscopy. In conjunction, calcium-handling protein expression was examined in left ventricular samples obtained from end-stage HF patients, in patients with either persistent atrial fibrillation or sinus rhythm. Compared with regularly paced ventricular cardiomyocytes, in cells paced irregularly for 24 hours, there was a significant reduction in the expression of sarcoplasmic reticulum calcium (Ca(2+)) ATPase together with reduced serine-16 phosphorylation of phospholamban. These findings were accompanied by a 59% reduction (P<0.01) in the peak Ca2+ transient in irregulary paced myocytes compared with those with regular pacing. Consistent with these observations, we observed a 54% (P<0.05) decrease in sarcoplasmic reticulum Ca(2+)ATPase protein expression and an 85% (P<0.01) reduction in the extent of phosphorylation of phospholamban in the left ventricular myocardium of HF patients in atrial fibrillation compared with those in sinus rhythm.</AbstractText>Together, these data demonstrate that ventricular rhythmicity contributes significantly to excitation-contraction coupling by altering the expression and activity of key calcium-handling proteins. These data suggest that control of rhythm may be of benefit in patients with HF.</AbstractText> |
13,749 | Cardiac arrhythmias in adult patients with asthma. | The pathogenesis of cardiac arrhythmias in asthma patients has not been fully elucidated. Adverse drug effects, particularly those of β2-mimetics, may play a role. The aim of this study was to determine whether asthma is associated with the risk of cardiac arrhythmias and electrocardiographic characteristics of arrhythmogenicity (ECG) and to explore the role of β2-mimetics.</AbstractText>A cross-sectional study was conducted among 158 adult patients with a diagnosis of asthma and 6303 participants without asthma from the cohort of the Utrecht Health Project-an ongoing, longitudinal, primary care-based study. All patients underwent extensive examinations, including resting 12-lead electrocardiogram (ECG) and pulmonary function tests. The primary outcome was "any arrhythmia on the ECG" (including tachycardia, bradycardia, premature ventricular contraction (PVC), and atrial fibrillation or flutter). Secondary outcomes were tachycardia, bradycardia, PVC, atrial fibrillation or flutter, mean heart rate, mean corrected QT (QTc) interval length, and prolonged QTc interval.</AbstractText>Tachycardia and PVCs were more prevalent in patients with asthma (3% and 4%, respectively) than those without asthma (0.6%, p < .001; 2%, p = .03, respectively). The prevalence of QTc interval prolongation was similar in participants with (2%) and without asthma (3%, odds ratio [OR]: 0.6 and 95% confidence interval [95% CI]: 0.2-2.0). In 74 asthma patients, who received β2-mimetics, tachycardia and PVCs were more common (OR: 12.4 [95% CI: 4.7-32.8] and 3.7 [95% CI: 1.3-10.5], respectively).</AbstractText>The adult patients with asthma more commonly show tachycardia and PVCs on the ECG than those without asthma. The patients with asthma received β2-mimetics; the risk of tachycardia and PVCs is even more pronounced.</AbstractText> |
13,750 | [The clinical usefulness of RAAS inhibitors in hypertensive patients]. | Many kinds of antihypertensive drugs have been used recently. JSH2009 supported that we should prescribe one of these drugs [calcium channel blockers, angiotensin receptor blockers (ARBs), angiotensin-converting enzyme (ACE) inhibitors, diuretics and beta-adrenergic blockers] for hypertensive patients at first. In this review, we provide a brief overview of the ARBs and ACE inhibitors and discuss the clinical evidence related to the use of ACE inhibitors and ARBs. In accordance with JSH2009, we summarize the clinical backgrounds which we should use ARB or ACE inhibitors for hypertensive patients with: left ventricular hypertrophy, heart failure, atrial fibrillation, old myocardial infarction, protein urea, renal disturbance, chronic cerebral stroke, diabetes mellitus, metabolic syndromes and the elderly. |
13,751 | Arrhythmias in pulmonary arterial hypertension. | Cardiac arrhythmias are important contributors to morbidity and mortality in patients with pulmonary arterial hypertension (PAH). Such patients manifest a substrate resulting from altered autonomics, repolarization abnormalities, and ischemia. Supraventricular arrhythmias such as atrial fibrillation and flutter are associated with worsened outcomes, and maintenance of sinus rhythm is a goal. Sudden death is a relatively common issue, though the contribution of malignant ventricular arrhythmias versus bradyarrhythmias differs from non-PAH patients. Congenital heart disease patients with PAH benefit from catheter ablation of medically refractory arrhythmias. Clinical studies of defibrillator/pacemaker therapy for primary prevention against sudden death in PAH patients are lacking. |
13,752 | [Isolated noncompaction cardiomyopathy with special emphasis on arrhythmia complications]. | Isolated noncompaction cardiomyopathy (NCCM) is a rare genetically determined myocardial disease caused by abnormal fetal development of the myocardium resulting in a thin compacted and a thicker noncompacted layer of the affected left ventricular (LV) wall. The genetic basis of NCCM is heterogenous. Diagnosis can be made using echocardiography or magnetic resonance imaging. The diagnostic criteria for NCCM are still under discussion. Afflicted patients may present with various symptoms caused by arrhythmias, heart failure and cardioembolic events. Severely reduced LV function as well as left bundle branch block and atrial fibrillation were shown to be linked to worse outcomes. Treatment in patients with NCCM should be targeted at individual symptoms and clinical findings. Therapy includes pharmacological treatment, and in individual cases ablation or device therapy, as well as consideration for heart transplantation in selected cases. Aside from regular clinical follow-up of patients with NCCM screening of first degree family members with assessment of medical history, physical examination, ECG recording, and echocardiography are recommended. |
13,753 | Intracardiac echocardiographic diagnosis of thrombus formation in the left atrial appendage: a complementary role to transesophageal echocardiography. | We sought to develop and validate an intracardiac echocardiography (ICE) imaging strategy for evaluation of left atrial (LA) appendage (LAA) anatomy and function to clarify equivocal findings of LAA thrombus with transesophageal echocardiography (TEE).</AbstractText>A total of 56 patients with ICE imaging of the LAA for thrombus evaluation before atrial fibrillation (AF) or ventricular tachycardia (VT) ablation were included for analysis. Serial views of the LAA were obtained for evaluating anatomic structures and flow as the ICE transducer was advanced from the right ventricular outflow tract to the pulmonary artery. ICE imaging of the LAA was selectively performed in 9 of 56 patients following equivocal findings of thrombus on TEE in order to evaluate the complementary role of ICE to TEE in the diagnosis of LAA thrombus.</AbstractText>ICE imaging of the LAA in 56 patients with AF (n = 42) or VT (n = 14) measured the long-(5.0 ± 1.0 cm) and short-axis dimension (1.8 ± 0.5 cm), and peak emptying flow velocity (50 ± 23 cm/s). Of 56 patients, 47 had ICE imaging of LAA with no thrombus. In the remaining 9 patients, 6 had "equivocal" LAA thrombus on TEE, with 3 of these 6 showing marked spontaneous echo contrast (SEC), whereas ICE detected one patient with LAA thrombus and the other 5 without thrombus (two with severe SEC/sluggish flow); the remaining 3 had "high suspicion" for thrombus detected by TEE, whereas ICE detected only one with LAA thrombus. Based on ICE diagnosis, two patients with LAA thrombus had the procedure cancelled, and all others had successful completion of the scheduled procedures.</AbstractText>ICE can provide serial assessment, multiple views, and detailed imaging of the LAA to reliably diagnose the presence of thrombus. Our findings support the use of ICE when equivocal TEE findings require confirmation prior to electrophysiological procedures.</AbstractText>© 2012, Wiley Periodicals, Inc.</CopyrightInformation> |
13,754 | [Etiology of severe pulmonary hypertension--possible role of metabolic syndrome]. | In clinical practice the association between obesity and pulmonary hypertension (PH) is not rare.</AbstractText>The aim of this study was to examine the prevalence of obesity and metabolic syndrome in patients with severe PH, especially cases without significant cardiac, pulmonary or vascular causes.</AbstractText>We retrospectively anaLyzed the records of 91 patients with severe PH in order to establish its causes.</AbstractText>A total of 64% of the patients were women. The women were older than the men, 76.5 years vs 74.0. The BMI of the women was higher than the men, 37.0 vs 30.07. The most common causes of severe PH seen in an internal medicine ward are: severe heart failure (45.1%), chronic lung disease (16.5%) or a combination of both (12.1%). Overall, 11% of our study patients were morbidly obese without significant cardiac, pulmonary or vascular causes of PH. This group was characterized by high incidence of diabetes meLLitus, arterial hypertension, hyperlipidemia, atrial fibrillation and left ventricular (LV) diastolic dysfunction.</AbstractText>Our results point to a possible association between metabolic syndrome and PH.</AbstractText> |
13,755 | [Arrhythmic storm in a patient with Brugada syndrome--an unusual case]. | Brugada syndrome is characterized by episodes of near sudden death or syncope. The heart is normal on physical, angiographic and echocardiographic examination. The characteristic ECG abnormalities consist of ST-segment elevation in leads V1-V3 and pseudo right bundle branch block. The ECG changes can be transient, causing the diagnosis to be missed. Provocative testing with Flecainide or other sodium channel blocking drugs can be used to unmask the ECG abnormalities. This is a case study of a young male who had been diagnosed as suffering from Brugada syndrome and had a defibrillator implanted five years ago. This time the patient was admitted because of syncope and documented an arrhythmic storm (seven episodes of ventricular fibrillation, treated with the implanted defibrillator). The episode occurred following extreme anger and an "exciting event", evoking sympathetic activity. The issue of a different form of autonomic modulation: involving sodium channels' activity in the heart (sympathetic rather than vagal) is raised. |
13,756 | Efficacy and safety of implantable cardiac defibrillators for treatment of ventricular arrhythmias in patients with cardiac sarcoidosis. | Implantable cardiac defibrillator (ICD) implantation is a class IIA recommendation for patients with cardiac sarcoidosis (CS). However, little is known about the efficacy and safety of ICDs in this population. The goal of this multicentre retrospective data review was to evaluate the efficacy and safety of ICDs in patients with CS.</AbstractText>Electrophysiologists at academic medical centres were asked to identify consecutive patients with CS and an ICD. Clinical information, ICD therapy history, and device complications were collected for each patient. Data were collected on 235 patients from 13 institutions, 64.7% male with mean age 55.6 ± 11.1. Over a mean follow-up of 4.2 ± 4.0 years, 85 of 234 (36.2%) patients received an appropriate ICD therapy (shocks and/or anti-tachycardia pacing) and 67 of 226 (29.7%) received an appropriate shock. Fifty-seven of 235 patients (24.3%) received a total of 222 inappropriate shocks. Forty-six adverse events occurred in 41 of 235 patients (17.4%). Patients who received appropriate ICD therapies were more likely to be male (73.8 vs. 59.6%, P = 0.0330), have a history of syncope (40.5 vs. 22.5%, P = 0.0044), lower left ventricular ejection fraction (38.1 ± 15.2 vs. 48.8 ± 14.7%, P ≤ 0.0001), ventricular pacing on baseline electrocardiogram (16.1 vs. 2.1%, P = 0.0002), and a secondary prevention indication (60.7 vs. 24.5%, P < 0.0001) compared with those who did not receive appropriate ICD therapies.</AbstractText>Patients with CS and ICDs are at high risk for ventricular arrhythmias. This population also has high rates of inappropriate shocks and device complications.</AbstractText> |
13,757 | Nodal recovery, dual pathway physiology, and concealed conduction determine complex AV dynamics in human atrial tachyarrhythmias. | The genesis of complex ventricular rhythms during atrial tachyarrhythmias in humans is not fully understood. To clarify the dynamics of atrioventricular (AV) conduction in response to a regular high-rate atrial activation, 29 episodes of spontaneous or pacing-induced atrial flutter (AFL), covering a wide range of atrial rates (cycle lengths from 145 to 270 ms), were analyzed in 10 patients. AV patterns were identified by applying firing sequence and surrogate data analysis to atrial and ventricular activation series, whereas modular simulation with a difference-equation AV node model was used to correlate the patterns with specific nodal properties. AV node response at high atrial rate was characterized by 1) AV patterns of decreasing conduction ratios at the shortening of atrial cycle length (from 236.3 ± 32.4 to 172.6 ± 17.8 ms) according to a Farey sequence ordering (conduction ratio from 0.34 ± 0.12 to 0.23 ± 0.06; P < 0.01); 2) the appearance of high-order alternating Wenckebach rhythms, such as 6:2, 10:2, and 12:2, associated with ventricular interval oscillations of large amplitude (407.7 ± 150.4 ms); and 3) the deterioration of pattern stability at advanced levels of block, with the percentage of stable patterns decreasing from 64.3 ± 35.2% to 28.3 ± 34.5% (P < 0.01). Simulations suggested these patterns to originate from the combined effect of nodal recovery, dual pathway physiology, and concealed conduction. These results indicate that intrinsic nodal properties may account for the wide spectrum of AV block patterns occurring during regular atrial tachyarrhythmias. The characterization of AV nodal function during different AFL forms constitutes an intermediate step toward the understanding of complex ventricular rhythms during atrial fibrillation. |
13,758 | Tachycardia-induced cardiomyopathy. | Tachycardia-induced cardiomyopathy (TIC) is an important cause of heart failure as it is potentially reversible after ventricular rate control. A 66-year-old hypertensive woman presented with a 15-day history of tachycardia, dyspnoea and oedema. ECG revealed atrial fibrillation with ventricular frequency of 130 beats per minute (bpm). Echocardiogram showed dilated left ventricle (LV) with 0.39 ejection fraction. Angiography revealed non-obstructed coronary arteries. Heart rate and cardiac failure were controlled with amiodarone, digoxine, captopril, metoprolol and furosemide. During follow-up, despite drug dose optimisation, the patient kept complaining of tachycardia and dyspnoea with a ventricular rate between 108 and 120&emsp14;bpm. Medical staff suspected she was not taking her medicines properly. Two months later, the patient was asymptomatic and had converted to sinus rhythm (heart rate of 76&emsp14;bpm). Echocardiogram showed normal LV size and function. Patient's diagnosis was TIC. Although rare, TIC should be considered in all cases of systolic dysfunction associated with tachyarrhythmia. |
13,759 | Cardiac arrests in schools: assessing use of automated external defibrillators (AED) on school campuses. | Sudden cardiac arrest in schools are infrequent, but emotionally charged events. The purpose of our study was to: (1) describe characteristics and outcomes of school cardiac arrests; and (2) assess the feasibility of conducting school bystander interviews to describe the events surrounding cardiac arrests, assess AED availability and use, and identify barriers to AED use.</AbstractText>We performed a telephone survey of bystanders to cardiac arrests occurring in K-12 schools in communities participating in the Cardiac Arrest Registry to Enhance Survival (CARES) database and a local cardiac arrest database. The study period was from 8/2005 to 8/2011 and continued in one community through 2011. Utstein style descriptive data and outcomes were collected. A structured telephone interview of a bystander or administrative personnel was conducted for each cardiac arrest event. We collected a descriptive event summary, including provision of bystander CPR, presence of an AED and information regarding AED deployment, training, and use and perceived barriers to AED use. Descriptive data are reported.</AbstractText>During the study period there were 30,603 cardiac arrests identified at study communities, of which 47 (0.15%) events were at K-12 schools. Of these, 21 (45.7%) were at high schools, a minority (16, 34.0%) were children (<age 19), most (39, 83.0%) were witnessed arrests, a majority (36, 76.6%) received bystander CPR, and 27 (57.4%) were initially in ventricular fibrillation (VF). Most arrests (28/40, 70%) occurred during the school day (7a-5p). From this population, 15 (31.9%) survived to hospital discharge. A telephone interview was completed for 30 of 47 K-12 events. Nineteen schools had an AED on site. Most schools (84.2%) with AEDs reported that they had a training program, and personnel identified for its use. An AED was applied in 11 of 19 patients, of these 8 were in VF and 4 (all VF) survived to hospital discharge. Bystanders identified multiple reasons for non-use of the AED in the other eight patients.</AbstractText>Cardiac arrests in schools are rare events, most patients are adults and receive bystander CPR. AED application by laypersons was infrequent but resulted in excellent (4/11) survival. AEDs were not used in a substantial proportion of incidents and further attention must be paid to planning for emergency response on school campuses. We also identified the difficulty in assessing school emergency care and advocate for the development of methods to evaluate the provision of emergency care on school campuses.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,760 | Retrospective evaluation of current-based impedance compensation defibrillation in out-of-hospital cardiac arrest. | Transthoracic impedance (TTI) is a principal parameter that influences the intracardiac current flow and defibrillation outcome. In this study, we retrospectively evaluated the performance of current-based impedance compensation defibrillation in out-of-hospital cardiac arrest (OHCA) patients.</AbstractText>ECG recordings, along with TTI measurements were collected from multiple emergency medical services (EMSs) in the USA. All the EMSs in this study used automated external defibrillators (AEDs) which employing rectilinear biphasic (RLB) waveform. The distribution and change of TTI between successive shocks, the influence of preceding shock results on the subsequent shock outcome, and the performance of current-based impedance compensation defibrillation was evaluated.</AbstractText>A total of 1166 shocks from 594 OHCA victims were examined in this study. The average TTI for the 1st shock was 134.8 Ω and a significant decrease in TTI was observed for the 2nd (p<0.001) and 3rd (p=0.033) sequential escalating shock. But TTI did not change after the 3rd shock. A higher success rate was observed for shocks with preceding defibrillation success. The success rate remained unchanged over the whole spectrum of TTI.</AbstractText>The average TTI was relatively higher in this OHCA population treated with RLB defibrillation as compared with previously reported data. TTI was significantly decreased after 1st and 2nd successive escalating shock but kept constant after the 3rd shock. Preceding shock success was a better predictor of subsequent defibrillation outcome other than TTI. Current-based impedance compensation defibrillation resulted in equivalent success rate for high impedance patients when compared with those of low impedance.</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,761 | Elevated pulmonary artery systolic pressures are associated with a lower risk of atrial fibrillation following lung transplantation. | Atrial fibrillation (AF) is common after open-chest procedures, but the etiology remains poorly understood. Lung transplant procedures allow for the study of novel contributing factors.</AbstractText>Records of lung transplant procedures performed at a single center between 2002 and 2009 were reviewed.</AbstractText>Of 174 patients, 27 (16%) had AF a median 6 days post-surgery. Post-operative AF patients less often had right ventricular hypertrophy (RVH) by either electrocardiogram (0 versus 14%, P=.042) or echocardiography (19% versus 47%, P=.006), and had lower pulmonary artery systolic pressures (PASP) (39 ± 12 versus 51 ± 22, P=.005). After multivariable adjustment, every 10-mm Hg increase in PASP was associated with a 31% reduction in the odds of post-operative AF (OR 0.69, 95% CI 0.49-0.98, P=.035). A higher pulmonary pressure was the only predictor independently associated with less post-operative AF.</AbstractText>Higher PASP was associated with a lower risk of AF after lung transplantation.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,762 | Immediate impact of successful percutaneous mitral valve commissurotomy on echocardiographic measures of right ventricular contractility. | Functional analysis of the right ventricle cannot be reliably evaluated by conventional echocardiography, because of its complex geometry and load dependence of ejection phase indices. The Tei index, dP/dt, and myocardial acceleration during isovolumic contraction are parameters of right ventricular (RV) contractility unaffected by RV geometry. However, the effect of loading conditions on these parameters is controversial. The aim of this study was to examine how afterload reduction observed after percutaneous transverse mitral commissurotomy (PTMC) in patients with mitral stenosis affects these measures of RV contractility.</AbstractText>Fifty-eight patients (mean age, 30.0 ± 8.3 years seven men, 52 women) with isolated rheumatic mitral stenosis, eight of whom had atrial fibrillation, were studied prospectively before and 24 to 48 hours after PTMC.</AbstractText>Immediately after PTMC, mitral valve area increased from 1.0 ± 0.2 to 1.8 ± 0.3 cm(2) (P = .0001). There was a significant decrease in systolic pulmonary artery pressure from 50.2 ± 26.9 to 33.2 ± 12.3 mm Hg (P = .0001), a decrease in the RV Tei index from 0.5 ± 0.2 to 0.3 ± 0.2 (P = .0001), and an increase in RV dP/dt from 321.0 ± 59.9 to 494.6 ± 139.5 mm Hg/sec (P = .0001). RV myocardial acceleration during isovolumic contraction and systolic velocity at the lateral tricuspid annulus assessed by Doppler tissue imaging did not change. There were weak positive correlations among the Tei index, dP/dt, and systolic pulmonary artery pressure before PTMC (respectively, r = 0.39, r = 0.28, and P = .02, P = .05) but not afterward (respectively, r = 0.17, r = 0.02, and P = .20, P = .90).</AbstractText>This study suggests that RV dP/dt and Tei index are weakly load dependent, whereas myocardial acceleration during isovolumic contraction is unaffected by acute change in RV afterload.</AbstractText>Copyright © 2012 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
13,763 | [Management of arrhythmia in patients with arterial hypertension]. | We estimated the risk of arrhythmic complications after the use of cardiovascular medications in a prospective study including 123 patients with arterial hypertension and recurrent atrial fibrillation. Dispersion characteristics of P wave and QT interval were studied in patients with left ventricular concentric remodeling, concentric hypertrophy, and eccentric hypertrophy. The role of therapy with beta-blockers. ACE inhibitors, and preductal in the reduction of the risk of atrial fibrillation and ventricular arrhythmia was evaluated. |
13,764 | Initial experience with Pomerantzeff's technique for reduction of the size of giant left atrium. | The most common indication for surgical correction of giant left atrium is associated with mitral valve insufficiency with or without atrial fibrillation. Several techniques for this purpose are already described with varying results.</AbstractText>To present the initial experience with the tangential triangular resection technique (Pomerantzeff).</AbstractText>From 2002 to 2010, four patients underwent mitral valve operation with reduction of left atrial volume by the technique of triangular resection tangential in our service. Three patients were female. The age ranged from 21 to 51 years old. The four patients presented with atrial fibrillation. Ejection fraction of left ventricle preoperatively ranged from 38% to 62%. The left atrial diameter ranged from 78mm to 140mm. After treatment of mitral dysfunction, the left atrium was reduced by resecting triangular tangential posterior wall between the pulmonary veins to avoid anatomic distortion of the mitral valve or pulmonary veins, reducing tension in the suture line.</AbstractText>Average hospital stay was 21.5 ± 6.5 days. The mean cardiopulmonary bypass time was 130 ± 30 minutes. There was no surgical bleeding or mortality in the postoperative period. All patients had sinus rhythm restored in the output of cardiopulmonary bypass, maintaining this rate postoperatively. The average diameter of the left atrium was reduced by 50.5% ± 19.5%. The left ventricular ejection fraction improved in all patients.</AbstractText>Initial results with this technique have shown effective reduction of the left atrium.</AbstractText> |
13,765 | QT variability paradox after premature ventricular contraction in patients with structural heart disease and ventricular arrhythmias. | Increased repolarization lability is known to be associated with the risk of ventricular tachycardia (VT)/ventricular fibrillation (VF). Premature ventricular contractions (PVCs) are excluded from the analysis of QT variability. However, QT dynamics after PVCs is poorly understood.</AbstractText>We analyzed data of 33 patients with structural heart disease (mean age 60.5 ± 12.1; 24 (73%) men; 26 (79%) whites; 22 (67%) ischemic cardiomyopathy) and single-chamber ICD implanted for primary (28 patients, 85%) or secondary prevention of SCD. Arrhythmia group comprised 16 patients with VT/VF/death outcomes. Alive patients (n = 17) without VT/VF served as controls. The baseline far-field (FF) ICD electrogram (EGM) was recorded at rest. RR and QT intervals of 15 sinus beats before and after PVC in 33 patients were analyzed. The prematurity index, C(i)Mean(RR), where C(i) is coupling interval, was used to select the most premature PVC. QT variability index (QTVI) was calculated. Difference in QTVI was calculated as QTVI(diff) = QTVI(after)-QTVI(before.)</AbstractText>In paired analysis QTVI significantly increased after PVC in controls (0.64 ± 1.02 vs. 0.26 ± 1.15; P = 0.046), but decreased in patients in the arrhythmia group (0.16 ± 0.85 vs. 0.43 ± 0.84; P = 0.190). QTVI(diff) was significantly lower in patients with VT/VF, as compared to controls (-0.197 ± 0.650 vs. 0.207 ± 0.723; P=0.030). In multivariate logistic regression after adjustment for the type of cardiomyopathy and NYHA class the decrease in QTVI after PVC was associated with increased risk of VT/VF (OR 9.24; 95% CI 1.11-76.82; P=0.040).</AbstractText>Elevated at baseline QTVI is decreased during first 15 beats after PVC in patients at risk for VT/VF.</AbstractText>Copyright © 2012 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,766 | Assessment of ventricular electrophysiological characteristics at periinfarct zone of postmyocardial infarction in rabbits following stellate ganglion block. | Assessment of Ventricular Electrophysiological Characteristics.</AbstractText>The aim of this study was to investigate the characteristics of ventricular electrophysiology following stellate ganglion block (SGB) at periinfarct zone in rabbits with myocardial infarction (MI).</AbstractText>Sixty-four rabbits were randomly assigned to 2 groups: MI (n = 32), ligation of the anterior descending coronary and sham operation (SO) (n = 32), without coronary ligation. Both MI and SO groups were divided into 4 subgroups according to right or left SGB and corresponding control (n = 8, each). After 8 weeks, 90% of monophasic action potential duration (MAPD90) of epicardium, midmyocardium and endocardium, transmural dispersion of repolarization (TDR), effective refractory period (ERP), and ventricular fibrillation threshold (VFT) were measured at the infarct border zone (MI group) and corresponding zone (SO group) following SGB. For SGB, 0.5 mL of 0.25% bupivacaine was used. Compared with the corresponding control group, in both the MI and SO groups, left SGB (LSGB) prolonged the MAPD90 of the 3 layers, reduced TDR, and increased ERP and VFT (P < 0.05). However, right SGB (RSGB) shortened MAPD90, increased TDR, and reduced ERP and VFT (P < 0.05).</AbstractText>The results of this study demonstrate that LSGB can increase the electrophysiological stability of ventricular myocardium.</AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,767 | Development and safety of an exercise testing protocol for patients with an implanted cardioverter defibrillator for primary or secondary indication. | Performing exercise tests in patients with an implantable cardioverter defibrillator (ICD) presents specific challenges because of susceptibility to ventricular arrhythmias during maximal levels of exertion. The purpose of this paper is to outline the exercise testing protocol from the Anti-Arrhythmic Effects of Exercise after an ICD trial and to report baseline test results and safety outcomes using the protocol.</AbstractText>Maximal cardiopulmonary exercise testing was performed to assess levels of physical fitness as part of a randomized trial of walking exercise in patients with ICDs. Subjects were randomized after baseline testing to aerobic exercise plus usual care or usual care alone. A modified Balke treadmill exercise test was used and specific ICD programming procedures were implemented to avoid unnecessary shocks, which included programming off ventricular tachycardia (VT) therapies during testing. To date, 161 baseline tests have been performed. One ventricular fibrillation (VF) cardiac arrest occurred following completion of an exercise test and three tests were stopped by the investigators due to nonsustained ventricular tachycardia. Eleven subjects were not able to achieve maximum exercise, defined as reaching an anaerobic threshold (AT) at baseline testing. There have been no deaths as a result of exercise testing.</AbstractText>Symptom-limited maximal exercise testing can be performed safely and effectively in patients with ICDs for both primary and secondary prevention indications. Specific strategies for ICD programming and preparation for treating ventricular arrhythmias needs to be in place before exercise testing is performed.</AbstractText> |
13,768 | [Do the guidelines always show us the ideal treatment of patients for cardiac resynchronisation therapy?]. | We present a case of 80-year-old man with chronic atrial fibrillation and heart failure with mildly depressed left ventricular ejection fraction who deteriorated after implantation of pacemaker to right ventricular apex. The patient improved when pacemaker was upgraded to resynchronisation therapy (CRT). The question is raised if CRT should have been implanted primarily. |
13,769 | May dual-source computed tomography angiography replace invasive coronary angiography in the evaluation of patients referred for valvular disease surgery? | Coronary computed tomography (CT) angiography is currently the only alternative to invasive angiography in the evaluation of coronary anatomy. In patients referred for valvular or thoracic aortic disease surgery, invasive coronary angiography remains the gold standard required by cardiac surgeons during the preoperative evaluation. According to the current European Society of Cardiology guidelines, evaluation of coronary anatomy is recommended in all patients above 40 years of age, with a history of coronary artery disease (CAD), in postmenopausal women, patients with left ventricular systolic dysfunction, with suspected ischaemic aetiology of mitral regurgitation, and in patients with one or more risk factors for CAD. The possibility to perform coronary CT angiography to exclude CAD before planned non-coronary cardiac surgery was first allowed in the 2010 Report of the American College of Cardiology Foundation Task Force on Expert Consensus.</AbstractText>To evaluate the usefulness of dual-source CT for the evaluation of coronary anatomy in patients before planned cardiac valvular surgery.</AbstractText>We studied 98 consecutive patients with a haemodynamically significant valvular heart disease and guideline-based indications for coronary angiography to exclude CAD before planned valvular surgery. Exclusion criteria included cardiac arrhythmia (atrial fibrillation, frequent ventricular and supraventricular premature beats), estimated glomerular filtration rate < 60 mL/min/1.73 m(2), allergy to iodine contrast agents, and lack of patient consent. Mean patient age was 58.8 (range 30-78) years. Coronary artery calcium score (CACS) was first determined in all patients. Coronary CT angiography was not performed if CACS was > 1000. In the remaining patients, complete CT evaluation was performed with the administration of a contrast agent. Conventional invasive coronary angiography was subsequently performed in patients with at least one > 50% stenosis, artifacts due to calcifications, or motion artifacts.</AbstractText>In 79 (80.6%) patients, CT angiography excluded the presence of a significant coronary artery stenosis without the need for invasive angiography. Conventional coronary angiography was required in 19 (19.4%) patients, including 13 (13.3%) patients with a > 50% stenosis in CT angiography, 2 (2%) patients with calcification artifacts, 1 (1%) patient with motion artifacts, 2 (2%) patients with CACS > 1000 in whom CT angiography was nor performed, and 1 (1%) patient with allergic symptoms during administration of a test dose of the contrast agent. Ultimately, significant CAD was diagnosed in 9 (9.2%) patients in whom coronary artery bypass surgery was also performed. In addition, vascular anomalies were diagnosed with cardiac CT angiography in 5 (5.1%) patients. In 14 patients, CT angiography was also used for previously planned evaluation of a coexisting aortic aneurysm.</AbstractText>Coronary CT angiography may be useful to exclude significant CAD in patients referred for valvular disease surgery.</AbstractText> |
13,770 | Prognosis of different types of atrial fibrillation in the primary angioplasty era. | Atrial fibrillation (AF) has been associated with a poor prognosis in patients with ST-segment elevation myocardial infarction. There is considerable controversy regarding the prognostic implications of different types of AF.</AbstractText>We analyzed 913 patients consecutively admitted to our center with ST-segment elevation myocardial infarction undergoing a primary percutaneous coronary intervention. Clinical, ECG, and angiographic data were collected. We carried out univariate and multivariate analysis, using a combined endpoint of death, reinfarction, stroke, and clinically relevant bleeding. AF was documented in 117 patients. Among them, 25 presented AF at admission (previous AF) and 92 developed new-onset AF (66% transient, 13% persistent). Patients with AF were older, more frequently men, and had a worse Killip class, and a poorer left-ventricular ejection fraction. When analyzing the different types of AF, patients with new-onset AF (persistent and transient) had a higher Killip class and a worse left-ventricular ejection fraction. AF was associated with significantly higher in-hospital mortality and with a greater incidence of in-hospital adverse events. An increase in in-hospital mortality was recorded both for previous and for new-persistent AF, but after adjusting for confounding factors, only persistent AF was found to carry a worse short-term prognosis.</AbstractText>In patients undergoing primary angioplasty in the stent era, AF is associated with a poor prognosis. This risk appears to be particularly high among patients with persistent AF.</AbstractText> |
13,771 | Endocardial mapping and catheter ablation for ventricular fibrillation prevention in Brugada syndrome. | Endocardial Mapping and Ablation of Brugada Syndrome.</AbstractText>Brugada syndrome (BS) is characterized by ST-segment elevation in the right precordial electrocardiogram (ECG) leads and episodes of ventricular fibrillation (VF). This study aimed to observe the feasibility of substrate modification by radiofrequency catheter ablation and its effects on VF storm.</AbstractText>Ten BS patients (all men; median age 36.5 years) with VF storm (group I, n = 4) and no VF storm (group II, n = 6) were enrolled in the study between August 2007 and December 2008. All patients underwent electrophysiological study using noncontact mapping. The multielectrode array was placed in the right ventricular outflow tract (RVOT). The isopotential map was analyzed during sinus rhythm and the region that had electrical activity occurring during J point to +60 (J+60) milliseconds interval of the V1 or V2 of surface ECG was considered as the late activation zone (LAZ) and also the substrate for ablation. LAZ was found in RVOT with variable distribution in both groups. Endocardial catheter ablation of the LAZ modified Brugada ECG pattern in 3 of 4 patients (75%) and suppressed VF storm in all 4 patients in group I during long-term follow-up (12-30 months). One patient had complete right bundle branch block from the ablation procedure.</AbstractText>LAZ on RVOT identified by noncontact mapping may serve as potential VF substrate in BS patients with VF episodes. Radiofrequency ablation on LAZ normalized ECG, suppressed VF storm, and reduced VF recurrence. The procedure is safe and may prevent VF occurrence.</AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,772 | A case of long QT syndrome having compound mutations of <i>KCNH2</i> and <i>SCN5A</i>. | Long QT syndrome (LQTS) is a hereditary ion channelopathy resulting in prolonged cardiac repolarization and abnormal prolongation of the QT interval on the electrocardiogram (ECG). The patients are likely to develop ventricular arrhythmias and sudden cardiac death. Molecular biology and basic electrophysiology studies revealed an approach to the management of patients with LQTS, which includes genotype-based risk stratification. A 16-year-old-woman with QT prolongation on ECG had frequent syncopal episodes and an attack of ventricular tachycardia followed by ventricular fibrillation. The <i>SCN5A</i> mutation (intravene sequence 4-1 c/t) in addition to the <i>KCNH2</i> mutation (Arg56Gln) was identified. Her mother and older sister were also diagnosed as having LQTS, but had only a single mutation (<i>KCNH2</i>). Her older sister had an episode of syncope, but her mother did not. Genetic analysis sometimes reveals 2 or more mutations in LQTS patients with clinical phenotypes of the Romano-Ward syndrome. Compound mutations in different LQTS-related genes are likely to modify clinical characteristics. In addition, comprehensive screening of LQTS-related genes might be needed when facing family members with different clinical manifestations. <<b>Learning objective:</b> Molecular biology and basic electrophysiology studies revealed an approach to the management of patients with LQTS, which includes genotype-based risk stratification. We described a case of LQTS having compound mutations of <i>KCNH2</i> and <i>SCN5A</i> who had frequent syncopal episodes and an attack of ventricular fibrillation. The mutations of 2 different genes were associated with a severe phenotype of LQTS. Comprehensive screening of LQTS-related genes might be needed for estimating the severity of LQTS.>. |
13,773 | Severe arrhythmia after lithium intoxication in a patient with bipolar disorder admitted to the intensive care unit. | Despite its narrow therapeutic index, lithium remains widely used as a mood stabilizer for the treatment of bipolar disease. The cardiac side-effects of lithium have been well documented, and may induce non-specific T-wave flattening, prolonged QT interval, sinus node dysfunction and also ventricular tachycardia and ventricular fibrillation. We report the case of a 61-year-old male patient diagnosed with bipolar disorder who developed life-threatening cardiac manifestations secondary to severe lithium poisoning. Although hemodialysis was performed and the arrhythmias were adequately treated, the patient died on the sixth day after hospital admission due hemorrhagic complications after tracheostomy. |
13,774 | Role of ventricular rate response on dementia in cognitively impaired elderly subjects with atrial fibrillation: a 10-year study. | The role of ventricular rate response (VRr) on the incidence of dementia in elderly subjects with cognitive impairment and atrial fibrillation (AF) is not known. Thus, we examined the ability of VRr to predict dementia in cognitively impaired elderly subjects with and without AF.</AbstractText>A total of 358 cognitively impaired elderly subjects (MMSE <24) with and without AF were stratified in low/high (<50/>90) and moderate (>50/<90 bpm) VRr. A 10-year follow-up was performed.</AbstractText>Cognitively impaired subjects with dementia at the end of the follow-up were 135 (37.7%): 33 in the presence (75.0%) and 102 (32.5%) in the absence of AF (p < 0.001). Multivariate analysis shows that AF is a strong predictor of dementia (hazard ratio, HR = 4.10; 95% confidence interval, CI = 1.80-9.30, p < 0.001). More importantly, low/high VRr (<50/>90 bpm) is predictive of dementia in the presence (HR = 7.70, 95% CI = 1.10-14.20, p = 0.03) but not in the absence (HR = 1.85; 95% CI = 0.78-4.47; p = 0.152) of AF.</AbstractText>This study demonstrates that AF predicts dementia in elderly subjects with cognitive impairment. Moreover, VRr seems to play a key role in the incidence of dementia in cognitively impaired elderly subjects with AF.</AbstractText>Copyright © 2012 S. Karger AG, Basel.</CopyrightInformation> |
13,775 | Pre-hospital body surface potential mapping improves early diagnosis of acute coronary artery occlusion in patients with ventricular fibrillation and cardiac arrest. | To determine whether 80-lead body surface potential mapping (BSPM) improves detection of acute coronary artery occlusion in patients presenting with out-of-hospital cardiac arrest (OHCA) due to ventricular fibrillation (VF) and who survived to reach hospital.</AbstractText>Of 645 consecutive patients with OHCA who were attended by the mobile coronary care unit, VF was the initial rhythm in 168 patients. Eighty patients survived initial resuscitation, 59 of these having had BSPM and 12-lead ECG post-return of spontaneous circulation (ROSC) and in 35 patients (age 69±13 yrs; 60% male) coronary angiography performed within 24 h post-ROSC. Of these, 26 (74%) patients had an acutely occluded coronary artery (TIMI flow grade [TFG] 0/1) at angiography. Twelve-lead ECG criteria showed ST-segment elevation (STE) myocardial infarction (STEMI) using Minnesota 9-2 criteria--sensitivity 19%, specificity 100%; ST-segment depression (STD) ≥0.05 mV in ≥2 contiguous leads--sensitivity 23%, specificity 89%; and, combination of STEMI or STD criteria--sensitivity 46%, specificity 100%. BSPM STE occurred in 23 (66%) patients. For the diagnosis of TFG 0/1 in a main coronary artery, BSPM STE had sensitivity 88% and specificity 100% (c-statistic 0.94), with STE occurring most commonly in either the posterior, right ventricular or high right anterior territories.</AbstractText>Among OHCA patients presenting with VF and who survived resuscitation to reach hospital, post-resuscitation BSPM STE identifies acute coronary occlusion with sensitivity 88% and specificity 100% (c-statistic 0.94).</AbstractText>Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,776 | The effect of the AED and AED programs on survival of individuals, groups and populations. | The automated external defibrillator (AED) is a tool that contributes to survival with mixed outcomes. This review assesses the effectiveness of the AED, consistencies and variations among studies, and how varying outcomes can be resolved.</AbstractText>A worksheet for the International Liaison Committee on Resuscitation (ILCOR) 2010 science review focused on hospital survival in AED programs was the foundation of the articles reviewed. Articles identified in the search covering a broader range of topics were added. All articles were read by at least two authors; consensus discussions resolved differences.</AbstractText>AED use developed sequentially. Use of AEDs by emergency medical technicians (EMTs) compared to manual defibrillators showed equal or superior survival. AED use was extended to trained responders likely to be near victims, such as fire/rescue, police, airline attendants, and casino security guards, with improvement in all venues but not all programs. Broad public access initiatives demonstrated increased survival despite low rates of AED use. Home AED programs have not improved survival; in-hospital trials have had mixed results. Successful programs have placed devices in high-risk sites, maintained the AEDs, recruited a team with a duty to respond, and conducted ongoing assessment of the program.</AbstractText>The AED can affect survival among patients with sudden ventricular fibrillation (VF). Components of AED programs that affect outcome include the operator, location, the emergency response system, ongoing maintenance and evaluation. Comparing outcomes is complicated by variations in definitions of populations and variables. The effect of AEDs on individuals can be dramatic, but the effect on populations is limited.</AbstractText> |
13,777 | Low doses of ranolazine and dronedarone in combination exert potent protection against atrial fibrillation and vulnerability to ventricular arrhythmias during acute myocardial ischemia. | Coronary artery disease carries dual risk for atrial tachyarrhythmias and sudden cardiac death.</AbstractText>To examine whether low-dose ranolazine and/or dronedarone can protect against vulnerability to atrial fibrillation (AF) and ventricular tachyarrhythmias.</AbstractText>In chloralose-anesthetized, open-chest Yorkshire pigs (n = 15), the proximal segment of left circumflex (LCx) coronary artery was occluded to reduce flow by 75%. An electrode catheter was positioned on the left atrial appendage to measure AF threshold (AFT) before and during LCx coronary artery stenosis before and at 1 hour after dronedarone (0.5 mg/kg intravenous bolus over 5 minutes) and/or ranolazine administration (0.6 mg/kg intravenous bolus followed by 0.035 mg/kg/min).</AbstractText>Before drug administration, LCx coronary artery stenosis lowered AFT from 25.2 ± 1.7 mA control (mean ± SEM) to 4.9 ± 1.0 mA baseline (P<.01). At the low doses, neither ranolazine (plasma concentration 2.4 ± 0.6 μM) nor dronedarone (plasma concentration 20.9 ± 3.5 nM) alone blunted the ischemia-induced reduction in AFT but were effective together (from 25.2 ± 1.7 mA control to 22.0 ± 3.0 mA during stenosis; P = not significant). AF duration (P<.03) and AF inducibility (P = .012) were reduced by ranolazine and dronedarone together but not by either drug alone. Concurrently, combined but not separate administration blunted the ischemia-induced surge in T-wave heterogeneity, a marker of risk for ventricular tachyarrhythmias (from 43.1 ± 11.1 μV control to 149.7 ± 15.1 μV during stenosis, P<.001, compared to 61.7 ± 13.7 μV control to 83.7 ± 15.8 μV during stenosis, P = not significant).</AbstractText>Combined administration of low doses of ranolazine and dronedarone exerts a potent antiarrhythmic action on ischemia-induced vulnerability to AF and ventricular tachyarrhythmias due to direct effects on myocardial electrical properties.</AbstractText>Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,778 | Atrial fibrillation pacing decreases intravascular shear stress in a New Zealand white rabbit model: implications in endothelial function. | Atrial fibrillation (AF) is characterized by multiple rapid and irregular atrial depolarization, leading to rapid ventricular responses exceeding 100 beats per minute (bpm). We hypothesized that rapid and irregular pacing reduced intravascular shear stress (ISS) with implication to modulating endothelial responses. To simulate AF, we paced the left atrial appendage of New Zealand White rabbits (n = 4) at rapid and irregular intervals. Surface electrical cardiograms were recorded for atrial and ventricular rhythm, and intravascular convective heat transfer was measured by microthermal sensors, from which ISS was inferred. Rapid and irregular pacing decreased arterial systolic and diastolic pressures (baseline, 99/75 mmHg; rapid regular pacing, 92/73; rapid irregular pacing, 90/68; p < 0.001, n = 4), temporal gradients ([Formula: see text] from 1,275 ± 80 to 1,056 ± 180 dyne/cm(2) s), and reduced ISS (from baseline at 32.0 ± 2.4 to 22.7 ± 3.5 dyne/cm(2)). Computational fluid dynamics code demonstrated that experimentally inferred ISS provided a close approximation to the computed wall shear stress at a given catheter to vessel diameter ratio, shear stress range, and catheter position. In an in vitro flow system in which time-averaged shear stress was maintained at [Formula: see text] , we further demonstrated that rapid pulse rates at 150 bpm down-regulated endothelial nitric oxide, promoted superoxide (O 2 (.-) ) production, and increased monocyte binding to endothelial cells. These findings suggest that rapid pacing reduces ISS and [Formula: see text] , and rapid pulse rates modulate endothelial responses. |
13,779 | Effects of propofol on ischemia-induced ventricular arrhythmias and mitochondrial ATP-sensitive potassium channels. | To investigate the potential of propofol in suppressing ventricular arrhythmias and to examine whether mitochondrial ATP-sensitive potassium channels are involved.</AbstractText>Male Sprague-Dawley rats were pretreated with intravenous infusion of propofol (Prop), a selective mitochondrial KATP channel inhibitor 5-hydroxydecanoate (5-HD), propofol plus 5-HD (Prop+5-HD), a potent mitochondrial K(ATP) channel opener diazoxide (DZ) or NS, respectively. The dosage of each drug was 10 mg/kg. The animals then underwent a 30 min-ligation of the left anterior descending artery. The severity of arrhythmias, the incidence of ventricular fibrillation (VF), and the time of the first run of ventricular arrhythmias were documented using an arrhythmia scoring system. Mitochondrial membrane potential (ΔΨm) was measured in freshly isolated rat cardiomyocytes with a fluorescence microscope.</AbstractText>The arrhythmia scores in the Prop and DZ group were 2.6(0-5) and 2.4(0-5), respectively, which were significantly lower than that in the control group [4.9(2-8)]. VF was not observed in both Prop and DZ groups. The first run of ventricular arrhythmias was significantly postponed in the Prop group (10.5±2.2 vs 7.3±1.9 min). Bracketing of propofol with 5-HD eliminated the anti-arrhythmic effect of propofol. In isolated rat cardiomyocytes, propofol (50 μmol/L) significantly decreased ΔΨm, but when propofol was co-administered with 5-HD, the effect on ΔΨm was reversed.</AbstractText>Propofol preconditioning suppresses ischemia-induced ventricular arrhythmias in the rat heart, which are proposed to be caused by opening of mitochondrial K(ATP) channels.</AbstractText> |
13,780 | [Predictors of reversion to sinus rhythm previous to electrical cardioversion in patients with persistent atrial fibrillation treated with anti-arrhythmic drugs]. | Some patients with persistent atrial fibrillation treated pharmacologically revert to sinus rhythm prior to electrical cardioversion. Knowledge of factors predicting this effect may be clinically useful.</AbstractText>Data were obtained from patients enrolled in the study REgistro sobre la cardioVERSión en España (REVERSE) and treated with antiarrhythmic drugs that potentially may cause pharmacological reversal. We analized by means of logistic regression predictive factors related to reversion to sinus rhythm precardioversion.</AbstractText>Of the 752 patients treated with antiarrhythmic drugs, 160 (21%) reverted to sinus rhythm without electrical cardioversion. Amiodarone was the most widely used active compound (82%) and apparently the most effective. However, differences with other antiarrhythmic drugs were not significant (amiodarone 22% versus other antiarrhythmic drugs 17%, P = .22). Lack of obesity (body mass index < 30 kg/m(2)) (odds ratio [OR] = 1.9; P = .006), duration of atrial fibrillation < 1 year (OR 3.4; P=.02) and the absence of structural heart disease (OR 1,59; P = .01) were identified as independent variables with predictive value of pharmacological reversal to sinus rhythm. Among patients treated with amiodarone who met these criteria, the frequency of successful treatment increased up to 31%.</AbstractText>In patients with persistent atrial fibrillation treated with anti-arrhythmic drugs, lack of obesity, duration of atrial fibrillation < 1 year and the absence of structural heart disease are predictors of reversion to sinus rhythm before electrical cardioversion.</AbstractText>Copyright © 2011 Elsevier España, S.L. All rights reserved.</CopyrightInformation> |
13,781 | Relationship between mean platelet volume and coronary blood flow in patients with atrial fibrillation. | Atrial fibrillation (AF) is associated with impaired coronary flow by means of Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC). Mean platelet volume (MPV) is elevated in patients with AF. In the present study we aimed to investigate the relationship between MPV and TFC in patients with AF in the absence of obstructive coronary artery disease (CAD).</AbstractText>This observational study enrolled 185 AF patients and 189 control subjects, all with angiographically documented normal coronary arteries. MPV was measured at baseline and mean TFC was assessed after diagnostic coronary angiography.</AbstractText>The MPV was 9.95±1.32 in the AF group and 9.02±1.16 in the control group (p<0.001). In AF patients, MPV was significantly correlated with mean TFC (r=0.419, p<0.001), AF duration (r=0.407, p<0.001), AF classification (r=0.378, p<0.001), systemic hypertension (r=0.165, p=0.024), diabetes mellitus (r=0.233, p=0.001), left ventricular ejection fraction (r=-0.347, p<0.001), and baseline use of diuretics (r=0.177, p=0.016). In linear regression analysis, mean TFC, left ventricular ejection fraction and diabetes mellitus were found to be independently associated with MPV (p<0.001, p=0.028 and p=0.045 respectively).</AbstractText>Mean platelet volume seems to be independently associated with coronary blood flow in patients with atrial fibrillation in the absence of obstructive coronary artery disease.</AbstractText>Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.</CopyrightInformation> |
13,782 | Two axial-flow Synergy Micro-Pumps as a biventricular assist device in an ovine animal model. | This study investigated the use of 2 Synergy Micro-Pumps for full biventricular assist device (BiVAD) support. We examined right-sided and left-sided hemodynamic parameters over a range of right-sided and left-sided pump speeds in an acute, fibrillating, non-beating-heart model in sheep.</AbstractText>Five juvenile sheep (43 ± 2 kg) were implanted with two Synergy Micro-Pumps (CircuLite Inc, Saddle Brook, NJ), 1 in the right (RV) and 1 in the left ventricle (LV), through a median sternotomy. The RVAD outflow graft was anastomosed end-to-side to the pulmonary artery and the LVAD outflow to the ascending aorta. After surgical implantation of both pumps, ventricular fibrillation was induced and hemodynamic parameters were measured at 9 different levels of RVAD pump speed (from 20,000 to 28,000 rpm at 1,000-rpm increments), while the speed of the LVAD was set constant at 24,000, then at 26,000, and finally, at 28,000 rpm.</AbstractText>At a fixed LVAD speed, RVAD and LVAD flow both increased identically as RVAD speed was increased. This was due to redistribution of blood volumes that resulted in resetting of pressure gradients across each pump and each vascular bed in a manner dictated by the pump pressure-flow characteristics. Results were similar with LVAD set at 24,000, 26,000, or 28,000 rpm. At the highest LVAD and RVAD speeds, flow averaged 3.1 ± 0.7 liters/min, and pressures in the right atrium, pulmonary artery, left atrium, and aorta averaged 2.2 ± 3.7, 24.4 ± 6.5, 22.4 ± 5.5, and 56.6 ± 8.5 mm Hg, respectively.</AbstractText>BiVAD support with the 2 Synergy Micro-Pumps is feasible and able to provide full hemodynamic support in sheep. This approach holds promise for providing biventricular partial support in humans and, in particular, for full support in small adults and children.</AbstractText>Copyright © 2012 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,783 | The cardiocerebral resuscitation protocol for treatment of out-of-hospital primary cardiac arrest. | Out-of-hospital cardiac arrest (OHCA) is a significant public health problem in most westernized industrialized nations. In spite of national and international guidelines for cardiopulmonary resuscitation and emergency cardiac care, the overall survival of patients with OHCA was essentially unchanged for 30 years--from 1978 to 2008 at 7.6%. Perhaps a better indicator of Emergency Medical System (EMS) effectiveness in treating patients with OHCA is to focus on the subgroup that has a reasonable chance of survival, e.g., patients found to be in ventricular fibrillation (VF). But even in this subgroup, the average survival rate was 17.7% in the United States, unchanged between 1980 and 2003, and 21% in Europe, unchanged between 1980 and 2004. Prior to 2003, the survival of patients with OHCA, in VF in Tucson, Arizona was less than 9% in spite of incorporating previous guideline recommendations. An alternative (non-guidelines) approach to the therapy of patients with OHCA and a shockable rhythm, called Cardiocerebral Resuscitation, based on our extensive physiologic laboratory studies, was introduced in Tucson in 2003, in rural Wisconsin in 2004, and in selected EMS areas in the metropolitan Phoenix area in 2005. Survival of patients with OHCA due to VF treated with Cardiocerebral Resuscitation in rural Wisconsin increased to 38% and in 60 EMS systems in Arizona to 39%. In 2004, we began a statewide program to advocate chest compression-only CPR for bystanders of witnessed primary OHCA. Over the next five years, we found that survival of patients with a shockable rhythm was 17.7% in those treated with standard bystander CPR (mouth-to-mouth ventilations plus chest compression) compared to 33.7% for those who received bystander chest-compression-only CPR. This article on Cardiocerebral Resuscitation, by invitation following a presentation at the 2011 Danish Society Emergency Medical Conference, summarizes the results of therapy of patients with primary OHCA treated with Cardiocerebral Resuscitation, with requested emphasis on the EMS protocol. |
13,784 | Effects of hypothermia on brain injury assessed by magnetic resonance imaging after cardiopulmonary resuscitation in a porcine model of cardiac arrest. | To evaluate the effects of hypothermia on cerebral edema and metabolism, a porcine model of cardiac arrest was assessed by magnetic resonance imaging during the first 72 hours after restoration of spontaneous circulation (ROSC).</AbstractText>Ventricular fibrillation was induced in 33 pigs. After 8 minutes of untreated ventricular fibrillation, 30:2 cardiopulmonary resuscitation was performed. After ROSC, 30 survival animals were randomly divided into normothermia group (n = 15) and hypothermia group (n = 15). The hypothermia group immediately received endovascular cooling to regulate temperature to 33°C, which was maintained for 12 hours, followed by passive rewarming at 0.5°C/h to 37°C. Diffusion-weighted imaging and (1)hydrogen proton magnetic resonance spectroscopy were acquired for each group at 6, 12, 24, and 72 hours after ROSC.</AbstractText>Compared with the normothermia group, the hypothermia group exhibited a higher 72-hour survival (73.3% vs. 33.3%, P = .028) and a superior neurological deficit score (P = .031). Cerebral injury was found in both groups, but a lesser decrease in the apparent diffusion coefficient and N-acetyl aspartate/creatinine (P < .05) and a greater increase in choline/creatinine (P < .05) were found in the hypothermia group.</AbstractText>Magnetic resonance imaging could effectively detect the dynamic trend of cerebral injury in a porcine model of cardiac arrest within the first 72 hours after ROSC. Hypothermia produced a protective effect on neurological function by reducing brain edema and formation of adverse metabolites.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,785 | Risk stratification in Wolff-Parkinson-White syndrome: the correlation between noninvasive and invasive testing in pediatric patients. | In Wolff-Parkinson-White (WPW) syndrome, rapid antegrade conduction of atrial tachyarrhythmias can result in ventricular fibrillation and sudden death. Antegrade conduction can be assessed through noninvasive testing or invasive electrophysiology study (EPS). We aimed to determine the correlation between noninvasive testing and EPS in a pediatric WPW population.</AbstractText>All WPW patients <21 years who underwent EPS over a 10-year period were identified. Noninvasive testing reviewed included electrocardiogram, Holter, and exercise stress test (EST). Patients were classified as low-risk if preexcitation was lost during any test. EPS data reviewed included antegrade conduction during atrial pacing and atrial fibrillation. Conduction through the accessory pathway (AP) to a cycle length ≤ 250 ms was considered rapid, otherwise patients were nonrapid. Sensitivity, specificity, positive (PPV), and negative predictive value (NPV) of noninvasive testing to correctly identify nonrapid conduction was calculated.</AbstractText>There were 135 EPS. Twenty-four patients (18%) were classified low-risk noninvasively. Two of the 24 (8%) had rapid conduction at baseline EPS. The sensitivity, specificity, PPV, and NPV of low-risk noninvasive testing to predict nonrapid conduction was 22%, 94%, 92%, and 31%, respectively. Sixteen of the 24 had low-risk EST and none had rapid conduction at baseline EPS. The specificity and PPV of low-risk EST were 100%.</AbstractText>Loss of preexcitation during noninvasive testing had high specificity and PPV for nonrapid antegrade conduction during baseline EPS. Abrupt loss of preexcitation during EST was a highly reliable noninvasive marker of nonrapid AP conduction at baseline in our pediatric WPW patients.</AbstractText>©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,786 | Pharmacologic rate versus rhythm-control strategies in atrial fibrillation: an updated comprehensive review and meta-analysis. | In patients with atrial fibrillation (AF), ventricular rate control with medications has been found to be noninferior in preventing clinical events, compared to a strategy converting patients to sinus rhythm and maintaining it with medications. Guidelines have accepted rate control as an acceptable therapeutic option. Most of the prior studies excluded patients without significant left ventricular dysfunction, or permanent AF.</AbstractText>The authors searched the PubMed, CENTRAL, and EMBASE databases for randomized controlled trials from 1966 to 2011. Trials included were direct head-to-head comparisons of rate- and rhythm-control strategy using pharmacological means. The primary outcome assessed was risk of all-cause mortality. We also assessed other pooled clinical endpoints using a random effects model (Mantel-Haenszel) between rate and rhythm-control strategies.</AbstractText>Ten studies (total N = 7,867) met inclusion/exclusion criteria. In-hospital mortality was not different between groups (P = 0.31). The rates of stroke, systemic embolism, worsening heart failure, myocardial infarction, and bleeding were also similar. However, rates of rehospitalization were much lower with a rate-control strategy (P = 0.007). An exploratory analysis in patients younger than 65 years revealed a rhythm-control strategy was superior to rate control in the prevention of all-cause mortality (P = 0.0007).</AbstractText>This systematic review suggests no difference in clinical outcomes with a rate or rhythm-control strategy with AF. However, rehospitalization rates appear to be lower with pharmacological rate control for all ages, while finding support for rhythm control in younger patients.</AbstractText>©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,787 | The predictive value of P-wave duration by signal-averaged electrocardiogram in acute ST elevation myocardial infarction. | The prognostic value of P-wave duration has been previously evaluated by signal-averaged ECG (SAECG) in patients with various arrhythmias not associated with acute myocardial infarction (AMI).</AbstractText>To investigate the clinical correlates and prognostic value of P-wave duration in patients with ST elevation AMI (STEMI).</AbstractText>The patients (n = 89) were evaluated on the first, second and third day after admission, as well as one week and one month post-AMI. Survival was determined 2 years after the index STEMI.</AbstractText>In comparison with the upper normal range of P-wave duration (<120 msec), the P-wave duration in STEMI patients was significantly increased on the first day (135.31 +/- 29.29 msec, P < 0.001), up to day 7 (127.17 +/- 30.02 msec, P = 0.0455). The most prominent differences were observed in patients with left ventricular ejection fraction (LVEF) < or = 40% (155.47 +/- 33.8 msec), compared to LVEF > 40% (128.79 +/- 28 msec) (P = 0.001). P-wave duration above 120 msec was significantly correlated with increased complication rate; namely, sustained ventricular tachyarrhythmia (36%), congestive heart failure (41%), atrial fibrillation (11%), recurrent angina (14%), and re-infarction (8%) (P = 0.012, odds ratio 4.267, 95% confidence interval 1.37-13.32). P-wave duration of 126 msec on the day of admission was found to have the highest predictive value for in-hospital complications including LVEF 40% (area under the curve 0.741, P < 0.001). However, we did not find a significant correlation between P-wave duration and mortality after multivariate analysis.</AbstractText>P-wave duration as evaluated by SAECG correlates negatively with LVEF post-STEMI, and P-wave duration above 126 msec can be utilized as a non-invasive predictor of in-hospital complications and low LVEF following STEMI.</AbstractText> |
13,788 | Radiofrequency catheter ablation for unifocal premature ventricular complexes triggering recurrent ventricular fibrillations in a young man without structural heart disease. | A 17-year-old man was referred for aborted sudden cardiac death. Ventricular fibrillation (VF) was recorded by automated external defibrillator. Post-resuscitation electrocardiograms showed frequent monomorphic premature ventricular complexes (PVCs), with left bundle branch block configuration and inferior axis. Cardiac arrest due to VF recurred twice within the initial 42 hours. Rhythm monitoring revealed multiple episodes of sustained VF triggered by a triplet of monomorphic PVCs having similar morphology with isolated PVCs. Comprehensive cardiologic workup revealed no structural heart disease and ion-channelopathies. With the impression of idiopathic VF triggered by unifocal PVCs of right ventricular outflow tract (RVOT) origin, radiofrequency catheter ablation was performed to prevent frequent VF recurrence before implantable cardioverter-defibrillator (ICD) implantation. After successful ablation of the origin of unifocal PVCs at anterolateral wall of RVOT, the burden of PVCs decreased remarkably and VF did not recur. The patient was discharged after ICD implantation. |
13,789 | The impact of height on the risk of atrial fibrillation: the Cardiovascular Health Study. | Atrial fibrillation (AF) is the most common sustained arrhythmia. Increased body size has been associated with AF, but the relationship is not well understood. In this study, we examined the effect of increased height on the risk of AF and explore potential mediators and implications for clinical practice.</AbstractText>We examined data from 5860 individuals taking part in the Cardiovascular Health Study, a cohort study of older US adults followed for a median of 13.6 (women) and 10.3 years (men). Multivariate linear models and age-stratified Cox proportional hazards and risk models were used, with focus on the effect of height on both prevalent and incident AF. Among 684 (22.6%) and 568 (27.1%) incident cases in women and men, respectively, greater height was significantly associated with AF risk [hazard ratio (HR)(women) per 10 cm 1.32, confidence interval (CI) 1.16-1.50, P < 0.0001; HR(men) per 10 cm 1.26, CI 1.11-1.44, P < 0.0001]. The association was such that the incremental risk from sex was completely attenuated by the inclusion of height (for men, HR 1.48, CI 1.32-1.65, without height, and HR 0.94, CI 0.85-1.20, with height included). Inclusion of height in the Framingham model for incident AF improved discrimination. In sequential models, however, we found minimal attenuation of the risk estimates for AF with adjustment for left ventricular (LV) mass and left atrial (LA) dimension. The associations of LA and LV size measurements with AF risk were weakened when indexed to height.</AbstractText>Independent from sex, increased height is significantly associated with the risk of AF.</AbstractText> |
13,790 | Establishing a donation after cardiac death model in pigs. | Due to the lack of human donors, several strategies have sought to expand the organ pool. Efforts to characterize donation after cardiac death (DCD) have included studies of cell viability, histological and immunohistochemical changes, and oxidative stress, which is known to negatively impact graft survival. A large animal model would be useful for these inquiries. Therefore, we sought to establish a DCD animal model in pigs.</AbstractText>We simulated non-heart-beating donation Maastricht II and III conditions in 24 pigs. Cardiac fibrillation was induced using 9-V direct current. After various times of ventricular fibrillation (1-10 minutes) with no mechanical and/or medical treatment to achieve cardiac output, reanimation was performed for 30 minutes prior to multiorgan donation. Then, a neurological status was performed. Blood samples were obtained at defined times tissue samples were stored in liquid nitrogen and subsequently embedded in paraffin and subjected to further analysis.</AbstractText>We established a DCD pig model in our laboratory by inducing cardiac fibrillation. Up to now, only DCD donation according to the Maastricht criteria II and III has been performed, but establishing all Maastricht criteria of DCDs seems to be feasible.</AbstractText>A DCD model in pigs enables us to characterize organ quality more precisely as well as evaluate amelioration of storage conditions and donor treatments in a large-animal model.</AbstractText>Copyright © 2012 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,791 | Race and improvements in the use of guideline-recommended therapies for patients with heart failure: findings from IMPROVE HF. | Race is associated with differences in use of guideline-recommended therapies for patients with heart failure (HF).</AbstractText>To evaluate whether a practice-based performance improvement intervention is associated with similar improvements in evidence-based care for black, white, and race-undocumented patients.</AbstractText>IMPROVE HF is a longitudinal evaluation of a performance improvement intervention on use of evidence-based therapies for outpatients with HF or prior myocardial infarction and left ventricular ejection fraction less than or equal to 35%. Data were available for 7605 patients. Changes in use of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, aldosterone antagonist, cardiac resynchronization therapy, implantable cardioverter-defibrillator therapy, anticoagulant for atrial fibrillation, and HF education were analyzed by patient race (black, white, or undocumented/missing). Multivariate analyses identified variables independently associated with changes in each therapy.</AbstractText>There were 686 black patients (9.0%) and 3238 white patients (42.6%), and race was undocumented for 3537 (46.5%). Baseline use of B-blockers and aldosterone antagonists was significantly higher in black patients than in the other 2 groups, and use of aldosterone antagonists and HF education was higher among black patients at 24 months. Postintervention use of 4 of 7 therapies increased equitably for the 3 groups, and treatment rates were similar between black and white patients for 5 of 7 individual quality measures. Improvements in care were independent of race.</AbstractText>These findings offer some indication that race-based differences in delivery of evidence-based HF care may be decreasing in outpatient cardiology practices. Application of clinical decision support and performance feedback may facilitate equitable improvements in HF care in outpatient settings regardless of patient race.</AbstractText>NCT00303979, wwwv.clinicaltrials.gov.</AbstractText> |
13,792 | Cardiac electrophysiology in mice: a matter of size. | Over the last decade, mouse models have become a popular instrument for studying cardiac arrhythmias. This review assesses in which respects a mouse heart is a miniature human heart, a suitable model for studying mechanisms of cardiac arrhythmias in humans and in which respects human and murine hearts differ. Section I considers the issue of scaling of mammalian cardiac (electro) physiology to body mass. Then, we summarize differences between mice and humans in cardiac activation (section II) and the currents underlying the action potential in the murine working myocardium (section III). Changes in cardiac electrophysiology in mouse models of heart disease are briefly outlined in section IV, while section V discusses technical considerations pertaining to recording cardiac electrical activity in mice. Finally, section VI offers general considerations on the influence of cardiac size on the mechanisms of tachy-arrhythmias. |
13,793 | Peri-atrial epicardial adipose tissue is associated with new-onset nonvalvular atrial fibrillation. | Atrial fibrillation (AF) is associated with considerable morbidity and mortality in patients with coronary artery disease (CAD). Epicardial adipose tissue (EAT) is recognized as an important inflammatory tissue that may exert deleterious effects on the adjacent left atrial (LA) wall. Multidetector computed tomography (MDCT) can accurately assess EAT's volume and distribution. This study used MDCT to investigate the effect of peri-atrial EAT on new-onset nonvalvular AF.</AbstractText>The study group consisted of 279 patients (176 men; age, 65±10 years) with no history of AF who underwent MDCT examination for evaluation of CAD. EAT was automatically identified on the basis of threshold attenuation values of -30 to -250 Hounsfield units. EAT volume was calculated as the sum of EAT area and subsequently divided into peri-atrial and peri-ventricular EAT. During follow-up of 3.3±1.0 years, AF occurred in 17 (6.1%) patients. Cox proportional hazards regression analysis indicated that male sex, and the LA and peri-atrial EAT volumes (P=0.03, P<0.001, and P<0.001, respectively) were independent predictors for future AF. The sensitivity and specificity for the prediction of AF using a peri-atrial EAT volume index of ≥27 ml/m(2) were 88% and 92%, respectively.</AbstractText>This is the first study demonstrating that peri-atrial EAT volume estimated by MDCT excellently predicted the development of new-onset AF in patients with CAD, independent of LA enlargement.</AbstractText> |
13,794 | Increased susceptibility to ischemia-induced ventricular tachyarrhythmias in depressed rats: Involvement of reduction of connexin 43. | Connexin 43 (Cx43) has been reported to contribute to the occurrence of ventricular arrhythmias during myocardial ischemia (MI). In this study, we investigated the expression of Cx43 and the incidences of ventricular tachyarrhythmias [i.e., ventricular tachycardia (VT) and ventricular fibrillation (VF)] during acute MI in chronic mild stress (CMS) in rats. Male Sprague-Dawley (SD) control and CMS rats were assigned into a sham operation (SO) group and a MI group. Ventricular tachyarrhythmias were assessed and Cx43 protein expression was measured by Western blotting. During 30-min ischemia, the incidences of VT (7/12, 58.3%) and VF (5/12, 41.7%) in the CMS-MI group were significantly decreased compared with those in the control-MI group (12/12, 100.0% and 11/12, 91.7%; P<0.05). The amount of total Cx43 of the CMS-SO group was significantly decreased to approximately 50% compared with that of the control-SO group (P<0.05). The 30-min ischemia did not result in a significant change in the amount of total Cx43 (total Cx43 is defined as the non-phosphorylated Cx43 and phosphorylated Cx43) compared to that of the SO group in CMS rats (P>0.05). The amount of non-phosphorylated Cx43 in the CMS-MI group was markedly increased compared to that of the CMS-SO group (P<0.05), suggesting that the relative amount of phosphorylated Cx43 was significantly decreased in CMS rats. The gap junctional permeability in the CMS-MI group (50.4±4.9%) was significantly decreased compared with the normal non-ischemic value in the CMS-SO group (100%). The present study suggested that the incidence of ischemia-induced ventricular tachyarrhythmias was markedly increased in depressed rats, which may be associated with the reduction of Cx43 protein expression in the ventricle of depressed rats. |
13,795 | Coronary subclavian steal syndrome causing acute myocardial infarction in a patient undergoing coronary-artery bypass grafting. | Coronary subclavian steal syndrome with retrograde blood flow in the left internal mammary-coronary bypass graft is a rare but severe complication of cardiac surgery. The authors present a case of a 68-year-old man after coronary-artery bypass grafting using an internal mammary artery. He had been suffering from angina pectoris for the last several years before surgery. The patient was resuscitated at home by emergency medical service because of primary ventricular fibrillation due to an acute myocardial infarction 5 years after surgery. An occlusion of the left subclavian artery with the retrograde blood flow in the left internal mammary coronary bypass was found. This could have been the cause of insufficiency in coronary blood flow and ischemia of the myocardial muscle. The subclavian artery occlusion was successfully treated with percutaneous transluminal angioplasty and implantation of 2 stents. The patient remained free of any symptoms 2 years after this procedure. |
13,796 | Comparison of outcomes after use of biphasic or monophasic defibrillators among out-of-hospital cardiac arrest patients: a nationwide population-based observational study. | The use and popularity of the biphasic waveform defibrillator as a replacement for the monophasic waveform defibrillator are increasing, but it is unclear whether this can improve the rate of survival among out-of-hospital cardiac arrest patients. This study aimed to verify the hypothesis that the outcome of out-of-hospital cardiac arrest patients who received defibrillation shock with the biphasic waveform defibrillator was better than that of patients who received defibrillation shock with the monophasic defibrillator.</AbstractText>This prospective, nationwide, population-based, observational study included 21 172 out-of-hospital cardiac arrest patients with initial ventricular fibrillation or pulseless ventricular tachycardia from January 1, 2005, through December 31, 2007. Defibrillation shock was performed by monophasic defibrillator on 8224 (39%) patients and by biphasic defibrillator on 12 948 (61%) patients. The rate of survival at 1 month with minimal neurological impairment was 11.6% (951/8192) in the monophasic defibrillator group and 12.8% (1653/12 928) in the biphasic defibrillator group. Hierarchical logistic regression analysis using a generalized estimation equation showed no significant difference between the biphasic and monophasic groups in 1-month survival with minimal neurological impairment (adjusted odds ratio, 1.07; 95% confidence interval, 0.91-1.26; P=0.42). Confirmatory propensity score analyses showed similar results.</AbstractText>Although monophasic defibrillators are being replaced by biphasic defibrillators, our nationwide population-based observational study failed to demonstrate a statistically significant association between defibrillation waveform and 1-month survival rate with minimal neurological impairment.</AbstractText> |
13,797 | Feasibility of defibrillation and automatic arrhythmia detection using an exclusively subcutaneous defibrillator system in canines. | This study reports the experimental process leading to development of an automatic totally subcutaneous implantable cardioverter defibrillator (SICD) system engineered for human use.</AbstractText>Two studies were conducted to test defibrillation and detection feasibility of an SICD system located in the left chest. In the first study, 2 pockets were created in 15 canines for placement of an anterior electrode adjacent to the left edge of the sternum and a lateral electrode at the site along the axillary line between the 4th and 6th intercostal space. Stainless steel flat electrodes with active surface areas of 5, 10, 20, and 25 cm(2) or rod electrodes were subsequently positioned and the defibrillation threshold (DFT) was measured for multiple combinations. In the second study, the ability to induce, detect, and provide shock delivery in response to ventricular fibrillation (VF) using an SICD system engineered for clinical use was tested in 5 canines. One hundred and three DFT tests with 11 different dual electrode combinations were performed. All combinations terminated VF with a DFT of 35 ± 16 J (range: 9-79 J). Nineteen VF episodes were induced and recognized by the chronic SICD, leading to automatic capacitor charge and shock delivery in all cases.</AbstractText>Subcutaneous defibrillation using different electrode combinations with shock energies less than 80 J terminated all induced VFs. An automatic SICD proved effective in detecting and activating shock delivery in all cases. </AbstractText>© 2012 Wiley Periodicals, Inc.</CopyrightInformation> |
13,798 | Spontaneous primary intraventricular hemorrhage: clinical features and early outcome. | Purpose. Primary hemorrhage in the ventricular system without a recognizable parenchymal component is very rare. This single-center retrospective study aimed to further characterize the clinical characteristics and early outcome of this stroke subtype. Methods. All patients with primary intraventricular hemorrhage included in a prospective hospital-based stroke registry over a 19-year period were assessed. A standardized protocol with 161 items, including demographics, risk factors, clinical data, neuroimaging findings, and outcome, was used for data collection. A comparison was made between the groups of primary intraventricular hemorrhage and subcortical intracerebral hemorrhage. Predictors of primary intraventricular hemorrhage were identified by logistic regression analysis. Results. There were 12 patients with primary intraventricular hemorrhage (0.31% of all cases of stroke included in the database) and 133 in the cohort of subcortical hemorrhage. Very old age (≥85 years) (odds ratio (OR) 9.89), atrial fibrillation (OR 8.92), headache (OR 6.89), and altered consciousness (OR 4.36) were independent predictors of intraventricular hemorrhage. The overall in-hospital mortality rate was 41.7% (5/12) but increased to 60% (3/5) in patients aged 85 years or older. Conclusion. Although primary intraventricular hemorrhage is uncommon, it is a severe clinical condition with a high early mortality. The prognosis is particularly poor in very old patients. |
13,799 | [Recovered sudden cardiac death associated with an early repolarization syndrome: case analysis and pratical aspects]. | In this article, we report the case of a 61-year-old man who presented a cardiac arrest which has been resuscitated successfully. An early repolarization syndrome has been diagnosed by the ECG recorded the first 3 days after admission. This abnormality disappeared after that. The patient received an implantable cardioverter-defibrillator. Practical messages to the clinician concerning early repolarization are provided in this article. |
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