Perspective:

Favorable cardiac remodeling is associated with improved outcome in patients with HF, and is believed to be one means by which pharmacologic therapies such as renin-angiotensin-aldosterone inhibitors work. CRT therapy is believed to improve outcomes by improving ventricular synchrony and inducing favorable remodeling, thereby reducing the nidus for fatal arrhythmias and reducing HF progression. In this analysis, echocardiographic definitions of ‘super-response’ were associated with increased event-free survival and fewer HF hospitalizations. Since patients who were super-responders had shorter durations of HF prior to device implant, smaller baseline LV volumes, and were less likely to have ischemic cardiac disease, two questions are raised: 1) are CRT benefits time-dependent and should a ‘sooner than later’ approach be undertaken before ‘fixed’ (fibrotic) adverse ventricular remodeling occurs, or 2) does a ‘super-response’ just identify patients with a reversible nonischemic cardiomyopathy that may have recovered devoid of CRT? This study is not powered for detailed multivariable analysis, but controlling for HF duration or requiring a minimal HF duration on maximal medical therapy would help sort out the latter question. Regardless, response to CRT should be assessed by clinical improvement in New York Heart Association and by examining the echocardiographic predictors above. Nonresponders are higher risk for adverse outcome, and may warrant referral to a HF specialist.