Cardiac resynchronization therapy in mild heart failure

It has been firmly established that cardiac resynchronization therapy (CRT) reduces symptoms and improves mortality in patients with moderate-to-severe chronic heart failure [New York Heart Association (NYHA) class III-IV], despite optimal heart failure medication and with wide QRS complex on the surface electrocardiogram as evidence of ventricular dyssynchrony, but not whether such treatment is efficacious in mildly symptomatic heart failure patients. In such patients, the treatment goal is to prevent disease progression rather than to improve symptoms. The REVERSE trial was the first randomized, controlled study of CRT in NYHA I-II patients. Cardiac resynchronization therapy in this study induced substantial reverse remodelling over 12-18-24 months of follow-up and was linked to a significant delay in the time to first heart failure hospitalization and eventually in the time to the combined endpoint of time to first heart failure hospitalization or death. The MADIT CRT designed as a morbidity-mortality study corroborated these findings with a significant reduction in heart failure events and significant reverse remodelling. These findings most likely will translate into a wider use of CRT in mildly symptomatic patients to prevent disease progression.