Exercise Interventions in Patients With Implantable Cardioverter-Defibrillators and Cardiac Resynchronization Therapy

A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract

Purpose: 

Physical activity improves outcomes across a broad spectrum of cardiovascular disease. The safety and effectiveness of exercise-based interventions in patients with implantable cardioverter-defibrillators (ICDs) including cardiac resynchronization therapy defibrillators (CRT-Ds) remain poorly understood.

Methods: 

We identified clinical studies using the following search terms: “implantable cardioverter-defibrillators”; “ICD”; “cardiac resynchronization therapy”; “CRT”; and any one of the following: “activity”; “exercise”; “training”; or “rehabilitation”; from January 1, 2000 to October 1, 2015. Eligible studies were evaluated for design and clinical endpoints.

Results: 

A total of 16 studies were included: 8 randomized controlled trials, 5 single-arm trials, 2 observational cohort trials, and 1 randomized crossover trial. A total of 2547 patients were included (intervention groups = 1215 patients, control groups = 1332 patients). Exercise interventions varied widely in character, duration (median 84 d, range: 23-168 d), and follow-up time (median 109 d, range: 23 d to 48 mo). Exercise performance measures were the most common primary endpoints (87.5%), with most studies (81%) demonstrating significant improvement. Implantable cardioverter-defibrillator shocks were uncommon during active exercise intervention, with 6 shocks in 635 patients (0.9%). Implantable cardioverter-defibrillator shocks in follow-up were less common in patients receiving any exercise intervention (15.6% vs 23%, OR = 0.68; 95% CI, 0.48-0.80, P < .001). o₂ peak improved significantly in patients receiving exercise intervention (1.98 vs 0.36 mL/kg/min, P < .001).

Conclusion: 

In conclusion, exercise interventions in patients with ICDs and CRT-Ds appear safe and effective. Lack of consensus on design and endpoints remains a barrier to broader application to this important patient population.

In Brief

We performed a systematic review and meta-analysis of exercise-based interventions in patients with implantable cardioverter-defibrillators including cardiac resynchronization devices. After review of 649 articles, 16 studies with 2547 patients were included. Most studies demonstrated significant improvement in exercise performance. Device shocks were less common in patients receiving any exercise intervention.