Non-classical indications for cardiac resynchronization therapy.

Based on randomized controlled studies, cardiac resynchronization therapy (CRT) is currently indicated in patients with systolic heart failure of New York Heart Association (NYHA) functional class III and IV, left ventricular ejection fraction <35% and wide QRS (>120 ms). Most of the enrolled patients were in sinus rhythm, were not previously paced and had mainly LBBB. Thus, there are uncertainties regarding several other populations, not included or underrepresented in the main studies. These populations include patients with atrial fibrillation (AF), previous pacemakers considered for upgrade to CRT, RBBB, narrow QRS <120 ms, NYHA functional class 120 ms). These indications are based on randomized controlled trials in which patients with these indications have been enrolled. Most of the patients enrolled into these studies were in sinus rhythm, were not previously paced and had left bundle branch block (LBBB) or another left intraventricular conduction delay. There are still uncertainties regarding several other populations that were not included or underrepresented in the main studies. These populations include patients with atrial fibrillation, patients with previous pacemakers who are being considered for upgrade to CRT, patients with right bundle branch block (RBBB), patients with narrow QRS <120 ms, patients with NYHA functional class lower than III, patients with low EF who need pacemakers for other indications and do not have wide QRS yet, and patients with predominantly right heart failure. We will review here our experience and the available literature to try to determine the benefits of CRT in these populations. RevIew Sheba Medical Center & Tel Aviv University, Tel Hashomer, Israel HOSPITAL CHRONICLES 2008, 3(1): 33–36 Correspondence to: Prof. Michael Glikson, MD Director of Pacing and Electrophysiology Heart Institute, Sheba Medical Center Tel Hashomer, Israel 52621 Tel/ Fax : 972-3-535 6605 E mail: [email protected] Key wORDS: cardiac resynchronization therapy; biventricular pacing; left bundle branch block; right bundle branch block; atrial fibrillation;