Review of Cardiac Resynchronization Therapy

This episode of JAMA Clinical Reviews explores cardiac resynchronization therapy (CRT) as a critical intervention for patients with heart failure and conduction system disease. Dr. Mihai Kalu, lead author of a recent narrative review in JAMA, explains the pathophysiology of cardiac dyssynchrony—particularly in the context of left bundle branch block and iatrogenic dyssynchrony from right ventricular pacing—and how CRT restores coordinated ventricular activation. The discussion emphasizes that CRT is not a substitute for guideline-directed medical therapy but a complementary treatment targeting the underlying electrical dysfunction that impairs heart function. Key indications include patients with heart failure and left bundle branch block with QRS duration >150 ms, those requiring significant right ventricular pacing (>20–40%), and those developing pacing-induced cardiomyopathy. Dr. Kalu outlines two main CRT approaches—biventricular pacing and conduction system pacing—and discusses patient selection, device follow-up, and safety with modern imaging. The episode concludes with a strong endorsement for early referral to electrophysiologists to improve survival, reduce hospitalizations, and enhance quality of life.