Role of cardiac resynchronization therapy in asymptomatic and mildly symptomatic heart failure

Cardiac resynchronization therapy (CRT) improves quality of life, left ventricular (LV) size and function, and mortality among moderate to severe symptomatic congestive heart failure (CHF) patients with decreased LV ejection fraction and QRS prolongation. Whether these benefits extend to similar groups with minimal or mild CHF is an area of ongoing investigation. Two small studies with limited follow-up demonstrated reverse remodeling but no symptomatic improvement. A recent, larger study in a population of asymptomatic or mildly symptomatic CHF patients with longer follow- up confirmed the beneficial effect of CRT on LV size and function; furthermore, it was the first study to show that CRT improves clinical outcome with delayed time to heart failure hospitalization. Ongoing trials of CRT in such patients will soon provide further data on morbidity and mortality.