The Past, Present and Future of Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) has revolutionized the care of the patients with heart failure with reduced ejection fraction and electrical dyssynchrony. The current guidelines for patient selection include measurement of left ventricular systolic function, QRS duration and morphology, and functional classification. Despite consistent and increasing evidence supporting CRT use in appropriate patients, CRT has been underutilized. Notwithstanding the heterogeneous definitions of non-response, more than one-third of patients demonstrate a lack of echocardiographic reverse remodeling or poor clinical outcome following CRT. Since the causes of this non-response are multifactorial, it will require multidisciplinary efforts to overcome including optimal patient selection, procedural strategies, as well as optimizing post-implant care in patients undergoing CRT. The innovations of novel pacing approaches combined with advanced imaging technologies may eventually offer a personalized CRT system uniquely tailored to each patient's dyssynchrony signature.