Non-response to Cardiac Resynchronization Therapy.

PURPOSE OF REVIEW: Cardiac resynchronization therapy (CRT) is an effective treatment option for therapy-refractory mild to severe heart failure (HF) patients with reduced ejection fraction and left ventricular (LV) conduction delay. Multiple clinical trials have shown that CRT improves cardiac function and overall quality of life, as well as reduces HF hospitalizations, health care costs, and mortality.

RECENT FINDINGS: Despite its effectiveness, the "non-response" rate to CRT is around 30%, remaining a major challenge that faces electrophysiologists and researchers. It has been recently suggested that the etiology of CRT non-response is multifactorial, and it requires a multifaceted approach to address it. In this focused review, we will summarize the definitions of CRT non-response, identify key factors for CRT non-response, and offer a simplified framework to address CRT non-response with the main goal of improving CRT outcomes.