Arrhythmia Management Devices

2407 More than 2 decades of research has established the role of cardiac resynchronization therapy (CRT) in medically refractory, mild to severe systolic heart failure (HF) with abnormal QRS duration and morphology. CRT confers a mortality benefit, reduces HF hospitalizations, and improves functional outcome in this population, but not all patients consistently demonstrate a positive CRT response. The reported nonresponder rate ranges between 20% and 40%, depending on the response criteria used. Efforts to improve response to CRT have focused on methods to optimize the correction of electrical and mechanical dyssynchrony (the primary target of CRT) and on improving patient selection and optimizing postimplant care. The present article reviews the state-of-the-art of CRT and discusses developments on potential promises and areas of controversy.