Meta-analysis of Risk of Ventricular Arrhythmias After Improvement in Left Ventricular Ejection Fraction During
Aiman Smer1, Alok Saurav1, Muhammad Soubhi Azzouz1
1Department of Cardiovascular Medicine, CHI Health Creighton University School of Medicine, Omaha, Nebraska.
Insights
Improvement in left ventricular ejection fraction (LVEF) significantly lowers the risk of ventricular arrhythmias and mortality in patients with implantable cardioverter-defibrillators (ICDs). However, inappropriate ICD therapies remain similar regardless of LVEF improvement.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Implantable cardioverter-defibrillators (ICDs) are crucial for preventing sudden cardiac death in patients with reduced left ventricular ejection fraction (LVEF).
- Limited data exist on the long-term efficacy of ICDs in patients whose LVEF improves after initial implantation.
- Understanding the impact of LVEF improvement on ICD therapy outcomes is essential for patient management and device indication.
Purpose of the Study:
- To evaluate the effect of LVEF improvement on the rate of ICD therapy during follow-up.
- To assess the impact of LVEF improvement on appropriate and inappropriate ICD therapies.
- To determine the association between LVEF improvement and all-cause mortality in patients with ICDs.
Main Methods:
- A meta-analysis was conducted, including sixteen studies with 3,959 patients.
- Patients were categorized based on LVEF improvement (>35%) versus persistent low LVEF (≤35%).
- Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated using random-effects modeling.
Main Results:
- Patients with improved LVEF experienced significantly lower rates of appropriate ICD therapy (3.3% vs. 7.2% per year; IRR 0.52; P <0.001).
- This reduction in appropriate ICD therapy was consistent across various subgroups, including ICD-only and cardiac resynchronization-defibrillator studies.
- All-cause mortality rates were significantly lower in the improved LVEF group (3.63% vs. 8.23% per year; IRR 0.49; P <0.001), while inappropriate ICD therapy rates were similar between groups.
Conclusions:
- Improvement in LVEF is associated with a substantially reduced risk of ventricular arrhythmias and mortality in patients with ICDs.
- Despite LVEF improvement, the rate of inappropriate ICD therapies remains comparable to patients with persistently low LVEF.
- These findings highlight the benefit of LVEF recovery in reducing adverse cardiac events but underscore the continued risk of inappropriate shocks.
Abstract:
Implantable cardioverter defibrillators (ICDs) reduce the risk of sudden cardiac death in patients with impaired left ventricular ejection fraction (LVEF). However, there are limited data on the long-term benefit of ICD therapy in patients whose LVEF subsequently improves. We conducted a meta-analysis to evaluate the effect of LVEF improvement on ICD therapy during follow-up. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were calculated using random-effects modeling. Sixteen studies with 3,959 patients were included in our analysis. Study arms were defined by LVEF improvement at follow-up (improved LVEF [>35%]: 1,622; low LVEF [≤35%] 2,337). Mean age (64.8 vs 64.9 years, p = 0.97) was similar, whereas men were overrepresented in the persistent low LVEF group (79% vs 72%, p <0.001). Appropriate ICD therapy rate was 9.7% (improved LVEF) versus 21.8% (low LVEF) over a median follow-up period of 2.9 years. In the meta-analysis, improved LVEF group had significantly lower (3.3% vs 7.2% per year IRR 0.52; CI 0.38 to 0.70; p <0.001) appropriate ICD therapies which was uniformly seen across all subgroups (ICD-only studies: IRR 0.59; p = 0.004) (cardiac resynchronization therapy-defibrillator-only studies: IRR 0.31; p = 0.002) (super-responder studies [mean LVEF > 45%]: IRR 0.53; p = 0.002). Inappropriate ICD therapy rates were, however, similar in both groups (3.01% vs 2.56% per year IRR 0.76; CI 0.43 to 1.36; p = 0.35). All-cause mortality rates in our meta-analysis favored (3.63% vs 8.23% per year IRR 0.49; CI 0.35 to 0.69; p <0.001) the improved LVEF group. In conclusion, our meta-analysis demonstrates that an improvement in LVEF is associated with a significantly reduced risk of ventricular arrhythmia and mortality. However, inappropriate ICD therapy rates remain similar.
More Related Videos
Related Concept Videos
01:29Cardiomyopathy V: Interprofessional Care
01:29Cardiomyopathy III: Hypertrophic Cardiomyopathy
01:30Cardiomyopathy II: Dilated Cardiomyopathy
01:30Dysrhythmias V: Evaluating Dysrhythmias
01:25ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias
01:18Endocarditis III: Medical Management