Cardiac Resynchronization Therapy for Heart Failure A Hammer in Search of Nails

A number of randomized clinical trials have clearlyestablished that cardiac resynchronization therapy (CRT) improves ventricular function and symptom status while reducing hospitalizations and mortality in heart failure patients with left ventricular ejection fraction (LVEF) 35% who have New York Heart Association class III or IV symptoms despite optimal medical management, are in sinus rhythm, and have evidence of ventricular electromechanical dyssynchrony.1 Because the outcomes for patients with heart failure remain poor despite maximal pharmacotherapy and because the magnitude of the benefits from CRT is similar to that reported for angiotensin-converting enzyme inhibitors and -blockers, the rapid increase in CRT device implants in patients with heart failure over the past few years is not surprising.2 Although ongoing trials continue to test the efficacy and safety of CRT in patient groups who were underrepresented or excluded from prior trials, the CRT evidence base is evolving and following the well-established pattern of investigation for technological advances in which health services researchers follow the clinical trialists into an area to evaluate the uptake, effectiveness, and safety of new technologies when deployed in routine clinical practice. As a first step in this process, the study by Piccini and colleagues3 in this week’s Circulation examines who is, and who is not, receiving CRT in routine clinical practice. Article p 926 In their prospective cohort study of patients hospitalize