Effects of CRT Optimization as Assessed by Cardiac MR

Cardiac resynchronization therapy (CRT), or atrial-synchronized biventricular (BiV) pacing, is an FDA-approved device therapy option for heart failure (HF) patients with reduced left ventricular ejection fraction and electrical dyssynchrony. A traditional CRT device has pacing leads implanted within the right atrium (RA), the right ventricle (RV), and within a coronary vein overlying the lateral or posterior left ventricle (LV). Within the past decade, various multi-center randomized controlled trials have reported improved quality of life, aerobic exercise capacity, LV systolic function and structure, as well as decreased hospitalization rates and mortality among patients with HF. Despite improvements in CRT technology with multipoint pacing, quadripolar leads, and adaptive pacing algorithms, approximately 30% of patients do not clinically benefit and are considered non-responders. This study looks to optimize CRT device programming in patients considered non-responders to CRTusing information obtained from standard ECG machines, and to assess acute and chronic effects of CRT optimization using cardiac magnetic resonance imaging (CMR).