Epicardial fat and the risk of atrial tachy-arrhythmia recurrence post pulmonary vein isolation: a computed tomography study.

Epicardial and Pericardia fat have been hypothesized to exert local and systemic pathogenic effects on nearby cardiac structures. The present study aimed to evaluate the impact of epicardial and pericardial fat volumes on the outcome of patients that underwent a first pulmonary vein isolation (PVI) with cryoablation. We included 130 consecutive patients with atrial fibrillation (AF) that underwent contrast enhanced ECG-gated cardiac computed tomography (CCT) before a PVI. The control group included 50 patients in normal sinus rhythm that underwent ECG-gated CT to rule out coronary artery disease. Epicardial and pericardial fat volumes were quantified with CCT. Patients with AF compared to patients with normal sinus rhythm (control group) had significantly larger epicardial (140.3 ± 58.1 vs. 55.9 ± 17.7 ml; respectively, P < 0.001) and pericardial (77.0 ± 35.5 ml vs. 27.2 ± 9.5 ml; respectively, P < 0.001) fat volumes. Among patients that underwent PVIs, those with AF recurrence had a greater epicardial (175.0 ± 54.4 ml vs. 130.7 ± SD 54.2 ml; respectively, P < 0.001) and pericardial (93.7 ± SD 42.8 vs. 72.5 ± SD 31.9 ml; respectively, P < 0.001) fat volumes, compared to patients with no AF recurrence. Multivariate analyses revealed that epicardial fat was an independent predictor of recurrence post-ablation (HR = 1.08, 95% CI 1.02-1.16 per 10-ml increase in volume; P = 0.009). Pericardial fat was associated with 7% increase in risk of recurrent AF (HR = 1.07, 95% CI 0.98-1.18; P = 0.117). Epicardial fat, assessed with contrast enhanced CCT, is an independent predictor of AF recurrence after PVI ablation.

Effect of fibrotic capsule debridement during generator replacement on cardiac implantable electronic device infection risk.

BACKGROUND: Cardiovascular implantable electronic device (CIED) replacement is increasingly common. It has been proposed that capsule removal at the time of CIED replacement may reduce infection rates. In this study, we aimed to assess how pocket capsule removal impacted infection rates in patients undergoing CIED replacement. METHODS: We retrospectively reviewed the medical records of patients who underwent CIED replacement from 2006 to 2016 at a single centre. We retrieved patient data, procedure details, and clinical outcomes. To evaluate the relationship between capsule removal and CIED infection, we used the Cox proportional hazard model, with adjustment for multiple variables. RESULTS: During the study period, 773 patients underwent device replacement. Of these patients, 194 (25%) underwent capsule debridement during the replacement procedure. The mean patient age was 75 ± 15 years, and 281 (36.3%) were females. The replaced CIEDs included DDD pacemakers (32%), VDD pacemakers (15%), VVI/AAI pacemakers (13%), defibrillators (22%), and cardiac resynchronization therapy devices (CRT-D/P) (17%). During an average follow-up of 3.6 years, 42 (5%) patients experienced a CIED infection. Multivariate analysis revealed that patients who underwent capsule removal had a significantly lower risk of CIED infection, with a hazard ratio of 0.32 (95% confidence interval, 0.12-0.83; P = 0.019). CONCLUSIONS: Capsule debridement during CIED replacement was associated with a significant reduction of CIED infection risk. There is a need for randomized controlled studies to confirm these findings.

Developing a risk score to predict mortality in the first year after implantable cardioverter defibrillator implantation: Data from the Israeli ICD Registry.

INTRODUCTION: Life expectancy of less than 1 year is usually a contraindication for implantable cardioverter defibrillator (ICD) implantation. The aim was to identify patients at risk of death during the first year after implantation. METHODS AND RESULTS: Data were derived from a prospective Israeli ICD Registry. Two groups of patients were compared, those who died and those who were alive 1 year after ICD implantation. Factors associated with 1-year mortality were identified on a derivation cohort. A risk score was established and validated. A total of 2617 patients have completed 1 year of follow-up after ICD or cardiac resynchronization therapy defibrillator (CRT-D) implantation. Age greater than 75 years (hazard ratio [HR], 2.7; 95% confidence interval [95% CI], 1.6 to 4.4), atrial fibrillation (AF; HR, 1.9; 95% CI, 1.12 to 3.17), chronic lung disease (HR, 2.0; 95% CI, 1.1 to 3.76), anemia (HR, 2.3; 95% CI, 1.3 to 3.93) and chronic renal failure (CRF; HR, 3.4; 95% CI, 1.74 to 6.6) were independent risk factors for 1-year mortality. We propose a simple AAACC ("triple A double C") score for prediction of 1-year mortality after ICD implantation: Age greater than 75 years (3 points(pts)), anemia (2 pts), AF (1 pt), CRF (3 pts) and chronic lung disease (1 pt). Mortality risk increased with rising number of points (from 1% with 0 pts to 12.5% with >4 pts). The risk score was evaluated with receiver operating characteristic curve and the area under the curve of the validation curve is 0.71 (95% CI, 0.66 to 0.76). CONCLUSIONS: Age greater than 75, AF, chronic lung disease, anemia, and CRF were independent risk factors for 1-year mortality. AAACC risk score identifies patients at high risk of death during 1 year after ICD implantation.

Arrhythmic Events in Brugada Syndrome: A Nationwide Israeli Survey of the Clinical Characteristics, Treatment; and Long-Term Follow-up (ISRABRU-VF).

BACKGROUND: Limited information exists about detailed clinical characteristics and management of the small subset of Brugada syndrome (BrS) patients who had an arrhythmic event (AE). OBJECTIVES: To conduct the first nationwide survey focused on BrS patients with documented AE. METHODS: Israeli electrophysiology units participated if they had treated BrS patients who had cardiac arrest (CA) (lethal/aborted; group 1) or experienced appropriate therapy for tachyarrhythmias after prophylactic implantable cardioverter defibrillator (ICD) implantation (group 2). RESULTS: The cohort comprised 31 patients: 25 in group 1, 6 in group 2. Group 1: 96% male, mean CA age 38 years (range 13-84). Nine patients (36%) presented with arrhythmic storm and three had a lethal outcome; 17 (68%) had spontaneous type 1 Brugada electrocardiography (ECG). An electrophysiology study (EPS) was performed on 11 patients with inducible ventricular fibrillation (VF) in 10, which was prevented by quinidine in 9/10 patients. During follow-up (143 ± 119 months) eight patients experienced appropriate shocks, none while on quinidine. Group 2: all male, age 30-53 years; 4/6 patients had familial history of sudden death age < 50 years. Five patients had spontaneous type 1 Brugada ECG and four were asymptomatic at ICD implantation. EPS was performed in four patients with inducible VF in three. During long-term follow-up, five patients received ≥ 1 appropriate shocks, one had ATP for sustained VT (none taking quinidine). No AE recurred in patients subsequently treated with quinidine. CONCLUSIONS: CA from BrS is apparently a rare occurrence on a national scale and no AE occurred in any patient treated with quinidine.

Gender-Related Differences in Outcomes of Patients with Cardiac Resynchronization Therapy.

BACKGROUND: Gender-related differences (GRD) exist in the outcome of patients with cardiac resynchronization therapy (CRT). OBJECTIVES: To assess GRD in patients who underwent CRT. METHODS: A retrospective cohort of 178 patients who were implanted with a CRT in a tertiary center 2005-2009 was analyzed. Primary outcome was 1 year mortality. Secondary endpoints were readmission and complication rates. RESULTS: No statistically significant difference was found in 1 year mortality rates (14.6% males vs. 11.8% females, P = 0.7) or in readmission rate (50.7% vs. 41.2%, P = 0.3). The complication rate was only numerically higher in women (14.7% vs. 5.6%, P = 0.09). Men more often had CRT-defibrillator (CRT-D) implants (63.2% vs. 35.3%, P = 0.003) and had a higher rate of ischemic cardiomyopathy (79.2% vs. 38.2%, P < 0.001). There was a trend to higher incidence of ventricular fibrillation/ventricular tachycardia in men before CRT implantation (29.9% vs. 14.7%, P = 0.07%). A higher proportion of men upgraded from implantable cardioverter defibrillator (ICD) to CRT-D, 20.8% vs. 8.8%, P = 0.047. On multivariate model, chronic renal failure was an independent predictor of 1 year mortality (hazard ratio [HR] 3.6; 95% confidence interval [95%CI] 1.4-9.5), CRT-D had a protective effect compared to CRT-pacemaker (HR 0.3, 95%CI 0.12-0.81). CONCLUSIONS: No GRD was found in 1 year mortality or readmission rates in patients treated with CRT. There was a trend toward a higher complication rate in females. Men were implanted more often with CRT-D and more frequently underwent upgrading of ICD to CRT-D.

High-grade atrioventricular block in patients with acute myocardial infarction. Insights from a contemporary multi-center survey.

High-grade atrioventricular block (HAVB) is a frequent complication of acute myocardial infarction (AMI) and is associated with increased morbidity and mortality. We aimed to evaluate the incidence, predictors, and prognostic significance of HAVB in a contemporary cohort of patients with AMI, in the recent era of early reperfusion. Patients with acute coronary syndromes (n=11,487) during the years 2000-2010 were included. Patients were divided into two groups: with HAVB (n=308, 2.7%) and without HAVB (n=11,179, 97.3%). The incidence of HAVB decreased from 4.2% in 2000 to 2.1% in 2010 (p for trend<0.01). Patients with HAVB were more likely to develop in-hospital complications. Independent predictors of developing HAVB were older age, ST-elevation myocardial infarction (STEMI), smoking and Killip class≥2 on admission. 30-day and 1-year mortality rates were significantly higher in the HAVB as compared to the non-HAVB group (24% vs. 4.9%, p<0.01, 33.5% vs. 10%, p<0.01, respectively). Multivariable logistic regression analysis revealed that, HAVB was associated with increased 30-day (OR - 3.97; 95% CI - 1.96-8.04) and 1-year mortality risk (HR - 2.02; 95% CI - 1.3-3.1). Similar estimates were obtained for STEMI and non-STEMI (NSTEMI). In conclusion, although the incidence of HAVB decreased over the last decade, the associated morbidity and mortality are still high in these patients despite early reperfusion therapy.

Syncope in Primary Prevention Implantable Cardioverter Defibrillator Implantation.

BACKGROUND: Syncope prognosis varies widely: 1 year mortality may range from 0% in the case of vasovagal events up to 30% in the presence of heart disease. OBJECTIVES: To assess the outcomes and prognosis of patients with implantable cardiac defibrillator (ICD) and indication of primary prevention and compare patients presenting with or without prior syncope. METHODS: We reviewed the charts of 75 patients who underwent ICD implantation with the indication of primary prevention and history of syncope and compared them to a control group of 80 patients without prior syncope. We assessed the number of ventricular tachycardia (VT), ventricular fibrillation (VF), shock, anti-tachycardia pacing (ATP), and death in each group during the follow-up. RESULTS: Mean follow-up was 893 days (810-976, 95% confidence interval) (no difference between groups). Patients with prior syncope had a higher ejection fraction (EF) (35.5 ± 12.6 vs. 31.4 ± 8.76, P = 0.02), more episodes of VT (21.3% vs. 3.8%, P = 0.001) and VF (8% vs. 0%, P = 0.01) and also received more electric shocks (18.7% vs. 3.8%, P = 0.004) and ATP (17.3% vs. 6.2%, P = 0.031). There were no differences in inappropriate shocks (6.7% vs. 5%, P = 0.74), in cardiovascular mortality (cumulative 5 year estimate 29.9% vs. 32.2% P = 0.97) and any death (cumulative 5 year estimate 38.1% vs. 48.9% P = 0.18) during the follow-up. CONCLUSIONS: Syncopal patients before ICD implantation seem to have more episodes of VT/VF and shock or ATP. No mortality differences were observed.

Yield of left ventricular dyssynchrony by gated SPECT MPI in patients with heart failure prior to implantable cardioverter-defibrillator or cardiac resynchronization therapy with a defibrillator: Characteristics and prediction of cardiac outcome.

BACKGROUND: Mechanical left ventricular dyssynchrony (MLVD) might contribute in the therapeutic decision-making in patients with heart failure (HF) prior to cardiac resynchronization therapy (CRT). Our aim was to assess MLVD in patients with HF prior to implantable cardioverter-defibrillator (ICD) compared to patients with CRT-D. METHODS: In a prospective study, patients with LVEF ≤ 35% who were scheduled for ICD or CRT-D, underwent gated SPECT myocardial perfusion imaging with technetium 99m sestamibi within 3 months prior procedure. MLVD was measured by phase analysis. RESULTS: The study cohort consisted of 143 patients, 71 with ICD and 72 with CRT-D. Age 68.3 ± 11 and LVEF 24 ± 6%. Phase standard deviation (SD) was 62.5 ± 18 and 59.7 ± 20 (P = NS), respectively. During follow-up of 23.7 ± 12.1 months, there were 10 vs 14 cardiac death in ICD and CRT-D, respectively (P = NS), hospitalization for HF, in 34 vs 53 (P < .001). In multivariate analysis, Phase SD was the independent predictor for cardiac death [HR 2.66 (95% CI 1.046-6.768), P = .04]. Kaplan-Meier curves of phase SD of 60° significantly identified ICD patients with and without cardiac deaths and hospitalization for HF exacerbation. CONCLUSIONS: MLVD by phase SD can identify patients with cardiac events and predict cardiac death in patients treated with ICD.

Female gender as independent risk factor of torsades de pointes during acquired atrioventricular block.

BACKGROUND: Female gender increases the risk of torsades de pointes (TdP) in the long QT syndrome, and this increased risk is assumed to be due to their longer QT interval. OBJECTIVE: The purpose of this study was to study the interplay between gender, duration of the QT interval, and risk of TdP during AV block. METHODS: We studied 250 patients (48% women) with AV block. QT interval was measured at the time of most severe bradycardia. We then constructed different receiver operating characteristic curves for the QTc of males and females for predicting TdP. RESULTS: As expected, patients with TdP had longer QTc intervals than did patients with uncomplicated AV block (564 ± 81 ms vs 422 ± 62 ms, P < .001). This correlation between longer QTc and higher risk of TdP was true for both genders. However, the QT of females with TdP was shorter than the respective value for males with TdP. Despite similar severity of bradycardia, the QT was shorter for females (QT 672 ± 88 ms vs 727 ± 57 ms for females with TdP vs males with TdP, P = .022). The QTc/TdP risk curve for females was shifted to the left in comparison to the pertinent graph for males. Female gender was an independent predictor of TdP. CONCLUSION: Women are at increased risk for developing TdP during AV block, but this increased risk is independent of their longer QT interval. Females develop TdP with QT intervals that are not necessarily arrhythmogenic for males.

Characteristics and outcomes of diabetic patients with an implantable cardioverter defibrillator in a real world setting: results from the Israeli ICD registry.

AIMS: There are limited data regarding the effect of diabetes mellitus (DM) on the risks of both appropriate and inappropriate implantable cardioverter defibrillator (ICD) therapy. The present study was designed to compare the outcome of appropriate and inappropriate ICD therapy in patients with or without DM. METHODS AND RESULTS: The risk of a first appropriate ICD therapy for ventricular tachyarrhythmias (including anti tachycardia pacing and shock) was compared between 764 DM and 1346 non-DM patients enrolled in the national Israeli ICD registry. We also compared the risks of inappropriate ICD therapy, and death or cardiac hospitalization between diabetic and non-diabetic patients. Diabetic patients were older, were more likely to have ischemic cardiomyopathy, lower ejection fraction, atrial fibrillation, and other co-morbidities. The 3-year cumulative incidence of appropriate ICD therapy was similar in the DM and non-DM groups (12 and 13%, respectively, p = 0.983). Multivariate analysis showed that DM did not affect the risk of appropriate ICD therapy (HR = 1.07, 95% CI 0.78-1.47, p = 0.694) or inappropriate therapy (HR = 0.72, 95% CI 0.42-1.23, p = 0.232). However, DM was associated with a 31% increased risk for death or cardiac hospitalization (p = 0.005). Results were similar in subgroup analyses including ICD and defibrillators with cardiac resynchronization therapy function recipients, primary or secondary prevention indication for an ICD. CONCLUSIONS: Despite a significant excess of cardiac hospitalizations and mortality in the diabetic population, there was no difference in the rate of ICD treatments, suggesting that the outcome difference is not related to arrhythmias.

Syncope in Primary Prevention Implantable Cardioverter Defibrillator Patients.

BACKGROUND: Syncope is a common clinical condition spanning from benign to life-threatening diseases. There is sparse information on the outcomes of syncopal patients who received an implantable cardiac defibrillator (lCD) for primary prevention of sudden cardiac death (SCD). OBJECTIVES: To assess the outcomes and prognosis of patients who underwent implantable cardiac defibrillator (ICD) implantation for primary prevention of SCD and compare them to patients who presented with or without prior syncope. METHODS: We compared the medical records of 75 patients who underwent ICD implantation for primary prevention of SCD and history of syncope to those of a similar group of 80 patients without prior syncope. We assessed the episodes of ventricular tachycardia (VT), ventricular fibrillation (VF), shock, anti-tachycardia pacing (ATP) and mortality in each group during follow-up. RESULTS: Mean follow-up was 893 days (810-976, 95% CI) (no difference between groups). There was no significant difference in gender or age. Patients with prior syncope had a higher ejection fraction rate (35.5 ? 12.6 vs. 31.4 8.76, P = 0.02), experienced more episodes of VT (21.3% vs. 3.8%, P = 0.001) and VF (8% vs. 0%, P = 0.01), and received more electric shocks (18.7% vs. 3.8%, P = 0.004) and ATP (17.3% vs. 6.2%, P = 0.031). There were no differences in inappropriate shocks (6.7% vs. 5%, P = 0.74), cardiovascular mortality (cumulative 5 year estimate 29.9% vs. 32.2%, P = 0.97) and any death (cumulative 5 year estimate 38.1% vs. 48.9%, P = 0.18). CONCLUSIONS: Patients presenting with syncope before ICD implantation seemed to have more episodes of VT/VF and shock or ATP. No differences in mortality were observed.

Type of Atrial Fibrillation and Clinical Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement.

BACKGROUND: There are limited data available regarding the relationship between atrial fibrillation (AF) clinical type, oral anticoagulation (OAC) treatment, and clinical outcome after transcatheter aortic valve replacement (TAVR). The study was designed to evaluate this relationship. METHODS: We analyzed data from the Rabin Medical Center TAVR registry, including 319 consecutive patients who underwent TAVR from 2008 to 2014. Patients were divided into three groups based on their history of AF: sinus rhythm (SR), paroxysmal AF (PAF), or nonparoxysmal AF (NPAF). RESULTS: There were 211 (66%), 56 (18%), and 52 (16%) patients in the SR, PAF, and NPAF groups, respectively. The cumulative risk for stroke or death at 2 years was highest among patients with NPAF (38%), but similarly low in PAF (15%) and SR patients (16%, P < 0.001). By multivariate analysis, patients with NPAF demonstrated a significantly higher risk of stroke or death (HR = 2.76, 95% CI 1.63-4.66, P < 0.001), as compared with SR. In contrast, patients with PAF had a similar risk of stroke or death compared with SR (HR = 0.80, P = 0.508). Patients with NPAF not treated with OAC demonstrated an 8.3-fold (P < 0.001) increased risk of stroke or death, whereas patients with PAF not treated with OAC had a similar risk of stroke or death compared with the SR group (HR = 1.25, P = 0.569). CONCLUSION: History of NPAF, but not PAF, is associated with a significant increased risk of stroke or death compared with sinus rhythm in patients undergoing TAVR.

Relationship between age and inappropriate implantable cardioverter-defibrillator therapy in MADIT-RIT (Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy).

BACKGROUND: There is limited data regarding the relationship between age and inappropriate therapy among patients with an implantable cardioverter-defibrillator (ICD) and resynchronization therapy. OBJECTIVES: We aimed to investigate this relationship and the effect of ICD programming on inappropriate therapy by age. METHODS: In the Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy (MADIT-RIT) 1500 patients were randomized to 3 ICD programming arms: (A) conventional with ventricular tachycardia (VT) therapy ≥170; (B) high-rate cutoff with VT therapy ≥200, and (C) prolonged 60-second delay for VT therapy ≥170. We investigated the relationship between age, the risk of inappropriate ICD therapy (including antitachycardia pacing [ATP] or shock), and ICD programming. RESULTS: Cumulative incidence function Kaplan-Meier graphs showed an inverse relationship between increasing quartiles of age (Q1: ≤55, Q2: 56-64, Q3: 65-71, and Q4: ≥72 years) and the risk for inappropriate therapy. Multivariate analyses showed that each increasing decade of life was associated with 34% (P < .001), 27% (P < .001), and 26% (P < .001) reduction in the risk of inappropriate shock, inappropriate ATP, and any inappropriate therapy, respectively. Treatment arms B and C as compared with arm A were associated with a significant reduction in the risk of inappropriate therapies across all age quartiles (P < .001 for all). CONCLUSIONS: Among patients with a primary prevention indication for an ICD, there is an inverse relationship between age and inappropriate ICD therapy. Innovative ICD programming of high-rate cutoff or prolonged delay for VT therapy is associated with significant reductions in inappropriate therapy among all age groups.

Outcome of contemporary acute coronary syndrome complicated by ventricular tachyarrhythmias.

AIM: To evaluate the incidence and prognostic implications of ventricular tachyarrhythmias (VTAs) complicating acute myocardial infarction (MI). METHODS AND RESULTS: We evaluated 7669 MI patients [ST elevation (n = 3573) and non-ST-elevation acute coronary syndrome (ACS) (n = 4096)] from the Acute Coronary Syndrome Israeli Survey for the incidence of VTA. Ventricular tachyarrhythmia occurred in 3.8% of patients [2.1% early (≤ 48 h) and 1.7% late (>48 h) VTA]. In-hospital mortality rates were higher for patients with VTA when compared with patients with no VTA (P < 0.001). Consistent with these findings, multivariable analysis demonstrated that early and late VTAs were associated with increased risk of in-hospital death [hazard ratio (HR) = 3.84; 95% confidence interval (CI) 1.77-6.78, P < 0.001, and HR = 8.23; 95% CI 4.84-13.98, P < 0.001, respectively]. In contrast, post-discharge outcomes demonstrated that only late VTA was independently associated with a significant increased risk of 30-day mortality (HR = 5.17; 95% CI 1.54-17.27, P = 0.007) with a trend towards an increased 1-year mortality risk (HR = 1.69; 95% CI 0.79-3.62, P = 0.17). The long-term risk associated with in-hospital VTA was driven by sustained ventricular tachycardia (VT) (HR = 3.28; 95% CI 1.92-5.60, P < 0.001) but not ventricular fibrillation (HR = 1.27; 95% CI 0.65-2.49, P = 0.47). CONCLUSIONS: Our findings suggest that in patients with ACS, both early and late VTAs are associated with an increased risk of in-hospital mortality. However, only late VTA, mostly sustained VT, is associated with long-term adverse outcome.

Association between Red Cell Distribution Width and Mortality after Cardiac Resynchronization Therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) is a non-pharmacological option for patients with heart failure and interventricular dyssynchrony. Elevated red cell distribution width (RDW) reflects higher size and heterogeneity of erythrocytes and is associated with poor outcome in patients with chronic heart failure. OBJECTIVES: To examine the association between RDW levels and outcomes after CRT implantation. METHODS: We conducted a cohort analysis of 156 patients (126 men, median age 69.0 years) who underwent CRT implantation in our institution during 2004-2008. RDW was measured at three time points before and after implantation. Primary outcome was defined as all-cause mortality, and secondary outcome as hospital re-admissions. We investigated the association between RDW levels and primary outcome during a median follow-up of 61 months. RESULTS: Ninety-five patients (60.9%) died during follow-up. Higher baseline RDW levels were associated with all-cause mortality (unadjusted HR 1.35, 95% CI 1.20-1.52, P < 0.001). On multivariate analysis adjusted for clinical, electrocardiographic and laboratory variables, baseline RDW levels were associated with mortality (HR 1.33, 95%CI 1.16-1.53). RDW levels 6 months and 12 months post-implantation were also associated with mortality (HR 1.22, 95%CI 1.08-1.38, P = 0.001; and HR 1.15, 95% CI 1.01-1.32, P = 0.02, respectively). Patients who were re-admitted to hospital during follow-up (n = 78) had higher baseline RDW levels as compared to those who were not (14.9%, IQR 14.0, 16.0% vs. 14.3%, IQR 13.7, 15.0%, respectively, P = 0.03). CONCLUSION: An elevated RDW level before and after CRT implantation is independently associated with all-cause mortality.

Clinical impact of defibrillation testing at the time of implantable cardioverter-defibrillator insertion.

BACKGROUND: Ventricular fibrillation is routinely induced during implantable cardioverter-defibrillator insertion to assess defibrillator performance, but this strategy is experiencing a progressive decline. We aimed to assess the efficacy of defibrillator therapies and long-term outcome in a cohort of patients that underwent defibrillator implantation with and without defibrillation testing. METHODS: Retrospective observational series of consecutive patients undergoing initial defibrillator insertion or generator replacement. We registered spontaneous ventricular arrhythmias incidence and therapy efficacy, and mortality. RESULTS: A total of 545 patients underwent defibrillator implantation (111 with and 434 without defibrillation testing). After 19 (range 9-31) months of follow-up, the death rate per observation year (4% vs. 4%; p = 0.91) and the rate of patients with defibrillator-treated ventricular arrhythmic events per observation year (with test: 10% vs. without test: 12%; p = 0.46) were similar. The generalized estimating equations-adjusted first shock probability of success in patients with test (95%; CI 88-100%) vs. without test (98%; CI 96-100%; p = 0.42) and the proportion of successful antitachycardia therapies (with test: 87% vs. without test: 80%; p = 0.35) were similar between groups. There was no difference in the annualized rate of failed first shock per patient and per shocked patient between groups (5% vs. 4%; p = 0.94). CONCLUSIONS: In this observational study, that included an unselected population of patients with a defibrillator, no difference was found in overall mortality, first shock efficacy and rate of failed shocks regardless of whether defibrillation testing was performed or not.

Long QT syndrome complicating atrioventricular block: arrhythmogenic effects of cardiac memory.

BACKGROUND: The magnitude of QT prolongation in response to bradycardia, rather than the bradycardia per se, determines the risk for torsade de pointes during atrioventricular block (AVB). However, we do not know why some patients develop more QT prolongation than others, despite similar bradycardia. We hypothesized that in patients who develop significant QRS vector changes during AVB, the effects of cardiac memory lead to excessive QT prolongation. METHODS AND RESULTS: We studied 91 patients who presented with AVB and who also had an ECG predating the bradyarrhythmia for comparison. We correlated changes in QRS morphology and axis taking place during AVB with the bradycardia-induced QT prolongation. Patients with and without QRS morphology changes at the time of AVB were of similar age and sex. Moreover, despite similar R-R interval during AVB, cases with a QRS morphology change had significantly longer QT (648 ± 84 versus 561 ± 84; P<0.001) than those without. Patients who developed a change in QRS morphology at the time of AVB had a 7-fold higher risk of developing long QT. This risk nearly doubled when the change in QRS morphology was accompanied by a change in QRS axis. CONCLUSIONS: Cardiac memory resulting from a change in QRS morphology during AVB is independently associated with QT prolongation and may be arrhythmogenic during AVB.

Renal dysfunction and clinical outcomes of patients undergoing ICD and CRTD implantation: data from the Israeli ICD registry.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT) reduce mortality in patients with heart failure (HF) and left ventricular dysfunction. However, their efficacy in patients with chronic kidney disease (CKD) is controversial. OBJECTIVE: We examined the association between renal dysfunction and clinical outcomes in patients undergoing ICD and CRT defibrillator (CRTD) implantation. METHODS: Data were collected from the Israeli ICD registry. Estimated glomerular filtration rate (eGFR) at implantation was assessed using the modification of diet in renal disease formula. Primary outcome was all-cause mortality. Secondary outcomes included the composite endpoints of death or HF and death or ventricular arrhythmias (ventricular tachycardia/ventricular fibrillation [VT/VF]); any hospitalizations; first appropriate and inappropriate ICD therapy. RESULTS: During the study period (July 2010-November 2012), 2,811 patients were implanted with ICD or CRTD. One-year follow-up data were available for 730 ICD patients and 453 CRTD patients. Patients with eGFR < 30 mL/minute/1.73 m(2) (n = 54, 4.6%) were older, had a higher prevalence of diabetes, hypertension, or ischemic heart disease. eGFR <30 mL/minute/1.73 m(2) was associated with increased mortality risk in ICD (HR 5.4; 95% CI 1.5-19.2), but not in CRTD patients (HR 0.9; 95% CI 0.1-7.5). Renal dysfunction was associated with the composite endpoints of death or HF and death or VT/VF in ICD, but not in CRTD patients. Mean eGFR during follow-up decreased by 8.0 ± 4.3 mL/minute/1.73 m(2) in ICD patients (P = 0.06) and by 1.8 ± 1.3 mL/minute/1.73 m(2) in patients with CRTD (P = 0.2). CONCLUSION: Based on this retrospective analysis, CKD is associated with adverse prognosis after ICD implantation, but not after CRTD implantation. GFR decreased in patients with ICD, but not in CRTD patients.

Prognostic value of left ventricular dyssynchrony by myocardial perfusion-gated SPECT in patients with normal and abnormal left ventricular functions.

BACKGROUND: Left ventricular (LV) dyssynchrony by phase analysis has been studied by myocardial perfusion imaging (MPI)-gated SPECT in patients with LV dysfunction in various clinical settings. We aimed to investigate the routine use of phase analysis with gated SPECT for predicting cardiac outcome. METHODS: Patients referred to a tertiary medical center in 2010-2011 prospectively underwent a gated SPECT and phase analysis, and follow-up for cardiac events. The values of clinical variables, MPI, LV function, and LV dyssynchrony in predicting cardiac events were tested by univariate and multivariate analyses. RESULTS: The study group included 787 patients (66.5 ± 11 years, 81% men) followed for a mean duration of 18.3 ± 6.2 months. There were 45 (6%) cardiac events defined as composite endpoint; cardiac death occurred in 26 patients, and the rest had new-onset or worsening heart failure and life-threatening arrhythmias. In multivariate analysis, it was shown that NYHA class, diabetes mellitus, and LVEF <50% were the independent predictors for composite endpoint. However, the independent predictors for cardiac mortality were NYHA class (for each increment in class) and phase standard deviation (SD) (for each 10° increment). CONCLUSION: Gated SPECT with phase analysis for the assessment of LV dyssynchrony can successfully predict cardiac death together with NYHA class, in patients with LV dysfunction.