Cardiac Resynchronization Therapy Upgrade for Pacemaker-Induced Cardiomyopathy: A Meta-Analysis

Background Pacemaker-induced cardiomyopathy (PICM) is a recognized complication of chronic right ventricular (RV) pacing. While upgrade to cardiac resynchronization therapy (CRT) is a standard treatment, the evidence base is heterogeneous, and the impact on mortality remains uncertain. Methods We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing upgrade to CRT versus continued RV pacing in patients with PICM. Primary endpoints were changes in left ventricular ejection fraction (LVEF), end-systolic volume (LVESV), and end-diastolic volume (LVEDV). Secondary endpoints included NT-proBNP, functional status, quality of life (QoL), and all-cause mortality. Data were pooled using a generic inverse-variance random-effects model. Subgroup analysis by trial design (crossover vs. parallel) and extensive sensitivity analyses was also performed. Results Seven randomized controlled trials (N = 594) met inclusion. CRT upgrade increased LVEF by 8.40 percentage points, 95% CI [4.73, 12.07], 95% PI [−0.58, 17.38], p < .001; reduced LVESV by 26.86 mL, 95% CI [−40.99, −12.74], 95% PI [−49.66, −4.07], p < .001; and reduced LVEDV by 23.52 mL, 95% CI [−39.83, −7.20], 95% PI [−52.71, 5.68], p = .005. Significant benefits were also observed for NT-proBNP, New York Heart Association (NYHA) class, and peak VO 2 . Effects were larger and more precise in parallel trials than in crossover trials for LVEF. Prediction intervals crossed the null for most outcomes, indicating setting-level variability in true effects. GRADE certainty was moderate for LVESV and NYHA and low to very low for other outcomes Conclusion In PICM, CRT upgrade improves ventricular remodeling, systolic function, and functional capacity, though certainty varies. Wide prediction intervals indicate context-dependent benefit; further trials should clarify long-term outcomes and optimize patient selection.