ABSTRACT
Cardiac resynchronization therapy (CRT) can be achieved using biventricular pacing systems in patients with symptomatic chronic heart failure who have a comorbidity of intraventricular conduction delay (IVCD) and QRS duration >120 ms. Current evidence suggests that approximately 70% of patients with IVCD who experience persistent New York Heart Association (NYHA) class III or IV heart failure symptoms despite maximal benefits of medical therapy, including diuretics, angiotensin intervention, and beta-blockade, have measurable improvement in their heart failure syndromes with the addition of CRT to their complex medication and device options.1-5 In a very short period of time, over 4000 patients have enrolled in randomized controlled trials to evaluate this intervention, leading to consensus agreement that CRT is a standard of care for appropriate patients.6 This rapid accumulation of data creates challenges to integrate principles from prospective trials into daily clinical practice. The intention of this chapter is to highlight commonalities of patient selection criteria for clinical trials with the expressed goal of using the currently accepted indications for CRT therapy to identify patients more likely to respond to this invasive therapy option.
