Summary

Although cardiac resynchronization therapy (CRT) is not currently recommended for heart failure (HF) patients with a QRS complex <120 msec, many such patients have evidence of mechanical dyssynchrony by echocardiography. The Echocardiography Guided Cardiac Resynchronization Therapy study [EchoCRT; Ruschitzka F et al. N Engl J Med 2013] was a prospective, multicenter, randomized, clinical trial designed to evaluate the effect of CRT on morbidity and mortality in patients with symptomatic HF, a QRS complex <130 msec, and evidence of mechanical dyssynchrony.