Ongoing Risk of Ventricular Arrhythmias and All-Cause Mortality at Implantable Cardioverter Defibrillator Generator Change: A Systematic Review and Meta-Analysis

Mid-term clinical outcomes and cardiac function in patients receiving cardiac contractility modulation

OBJECTIVES

To describe the mid-term clinical and functional cardiac contractility modulation therapy (CCM) recipients in an urban population with heart failure.

BACKGROUND

CCM is a non-excitatory electrical therapy for patients with systolic heart failure with NYHA class III symptoms and ejection fraction (EF) 25-45%. How CCM affects a broad range of clinical measures, including diastolic dysfunction (DD) and weight change, is unexplored.

METHODS

We reviewed 31 consecutive patients at our center who underwent CCM implant. NYHA class, hospitalizations, ejection fraction (EF), diastolic function, and weight were compared pre- and post-CCM implant.

RESULTS

Mean age and follow-up time was 63 ± 10 years and 1.4 ± 0.8 years, respectively. Mean NYHA class improved by 0.97 functional classes (p < 0.001), and improvement occurred in 68% of patients. Mean annualized hospitalizations improved (0.8 ± 0.8 vs. 0.4 ± 1.0 hospitalizations/year, p = 0.048), and after exclusion of a single outlier, change in annualized days hospitalized also improved (total cohort 3.8 ± 4.7 vs. 3.7 ± 14.8 days/year; p = 0.96; after exclusion, 3.8 ± 4.7 vs. 1.1 ± 1.9 days/year, p < 0.001). Mean EF improved by 8% (p = 0.002), and among those with DD pre-CCM, mean DD improvement was 0.8 "grades" (p < 0.001). Mean weight change was 8.5 pounds lost, amounting to 4% of body weight (p = 0.002, p = 0.002, respectively), with 77% of patients having lost weight after CCM. Five patients (16%) experienced procedural complications; incidence skewed toward early implants.

CONCLUSION

In an observational cohort, CCM therapy resulted in improvement in NYHA class, hospitalizations, systolic and diastolic function, and weight.

Risk of ventricular arrhythmias following implantable cardioverter-defibrillator generator change in patients with recovered ejection fraction: Implications for shared decision-making

INTRODUCTION

Guidelines indicate primary-prevention implantable cardioverter-defibrillators (ICDs) for most patients with left ventricular ejection fraction (LVEF) ≤ 35%. Some patients' LVEFs improve during the life of their first ICD. In patients with recovered LVEF who never received appropriate ICD therapy, the utility of generator replacement upon battery depletion remains unclear. Here, we evaluate ICD therapy based on LVEF at the time of generator change, to educate shared decision-making regarding whether to replace the depleted ICD.

METHODS

We followed patients with a primary-prevention ICD who underwent generator change. Patients who received appropriate ICD therapy for ventricular tachycardia or ventricular fibrillation (VT/VF) before generator change were excluded. The primary endpoint was appropriate ICD therapy, adjusted for the competing risk of death.

RESULTS

Among 951 generator changes, 423 met inclusion criteria. During 3.4 ± 2.2 years follow-up, 78 (18%) received appropriate therapy for VT/VF. Compared to patients with recovered LVEF > 35% (n = 161 [38%]), those with LVEF ≤ 35% (n = 262 [62%]) were more likely to require ICD therapy (p = .002; Fine-Gray adjusted 5-year event rates: 12.7% vs. 25.0%). Receiver operating characteristic analysis revealed the optimal LVEF cutoff for VT/VF prediction to be 45%, the use of which further improved risk stratification (p < .001), with Fine-Gray adjusted 5-year rates 6.2% versus 25.1%.

CONCLUSION

Following ICD generator change, patients with primary-prevention ICDs and recovered LVEF have significantly lower risk of subsequent ventricular arrhythmias compared to those with persistent LVEF depression. Risk stratification at LVEF 45% offers significant additional negative predictive value over a 35% cutoff, without a significant loss in sensitivity. These data may be useful during shared decision-making at the time of ICD generator battery depletion.

Special Issue: Latest Advances in Delivery and Outcomes of Cardiac Resynchronization Therapy and Conduction System Pacing

Cardiac Resynchronization Therapy (CRT) is an established technique to improve morbidity and mortality in selected heart failure patients [...].

Incidence and Predictors of Implantable Cardioverter-defibrillator Therapies After Generator Replacement-A Pooled Analysis of 31,640 Patients' Data

Among primary prevention implantable cardioverter-defibrillator (ICD) recipients, 75% do not experience any appropriate ICD therapies during their lifetime, and nearly 25% have improvements in their left ventricular ejection fraction (LVEF) during the lifespan of their first generator. The practice guidelines concerning this subgroup's clinical need for generator replacement (GR) remain unclear. We conducted a proportional meta-analysis to determine the incidence and predictors of ICD therapies after GR and compared this to the immediate and long-term complications. A systematic review of existing literature on ICD GR was performed. Selected studies were critically appraised using the Newcastle-Ottawa scale. Outcomes data were analyzed by random-effects modeling using R (R Foundation for Statistical Computing, Vienna, Austria), and covariate analyses were conducted using the restricted maximum likelihood function. A total of 31,640 patients across 20 studies were included in the meta-analysis with a median (range) follow-up of 2.9 (1.2-8.1) years. The incidences of total therapies, appropriate shocks, and anti-tachycardia pacing post-GR were approximately 8, 4, and 5 per 100 patient-years, respectively, corresponding to 22%, 12%, and 12% of patients of the total cohort, with a high level of heterogeneity across the studies. Greater anti-arrhythmic drug use and previous shocks were associated with ICD therapies post-GR. The all-cause mortality was approximately 6 per 100 patient-years, corresponding to 17% of the cohort. Diabetes mellitus, atrial fibrillation, ischemic cardiomyopathy, and the use of digoxin were predictors of all-cause mortality in the univariate analysis; however, none of these were found to be significant predictors in the multivariate analysis. The incidences of inappropriate shocks and other procedural complications were 2 and 2 per 100 patient-years, respectively, which corresponded to 6% and 4% of the entire cohort. Patients undergoing ICD GR continue to require therapy in a significant proportion of cases without any correlation with an improvement in LVEF. Further prospective studies are necessary to risk-stratify ICD patients undergoing GR.