Cardiac resynchronization therapy in patients with a prior history of atrial fibrillation: Insights from four major clinical trials

Aims: To investigate the association of cardiac resynchronization therapy (CRT) on outcomes among participants with and without a history of atrial fibrillation (AF). Methods: Individual-patient-data from four randomized trials investigating CRT-Defibrillators (COMPANION, MADIT-CRT, REVERSE) or CRT-Pacemakers (COMPANION, MIRACLE) were analyzed. Outcomes were time to a composite of heart failure hospitalization or all-cause mortality or to all-cause mortality alone. The association of CRT on outcomes for patients with and without a history of AF was assessed using a Bayesian-Weibull survival regression model adjusting for baseline characteristics. Results: Of 3964 patients included, 586 (14.8%) had a history of AF; 2245 (66%) were randomized to CRT. Overall, CRT reduced the risk of the primary composite endpoint (hazard ratio [HR]: 0.69, 95% credible interval [CI]: 0.56–0.81). The effect was similar (posterior probability of no interaction = 0.26) in patients with (HR: 0.78, 95% CI: 0.55–1.10) and without a history of AF (HR: 0.67, 95% CI: 0.55–0.80). In these four trials, CRT did not reduce mortality overall (HR: 0.82, 95% CI: 0.66–1.01) without evidence of interaction (posterior probability of no interaction = 0.14) for patients with (HR: 1.09, 95% CI: 0.70–1.74) or without a history of AF (HR: 0.70, 95% CI: 0.60–0.97). Conclusion: The association of CRT on the composite endpoint or mortality was not statistically different for patients with or without a history of AF, but this could reflect inadequate power. Our results call for trials to confirm the benefit of CRT recipients with a history of AF.