Ventricular Resynchronization

ardiac resynchronization therapy (CRT) is a new therapy that improves hemodynamics and symptoms in patients with advanced heart failure (HF). Resynchronization pacing can influence hemodynamics by improving mechanical synchrony both between and within the right and left ventricles, as well as by optimizing atrioventricular synchrony. Biventricular pacing devices, first implanted in 1994, were approved by the U.S. Food and Drug Administration in 2001. Currently available devices may also have defibrillation capacity. Much of the information regarding the clinical benefits of CRT derives from clinical trials 2-4 (Table ) that together demonstrate that CRT improves symptoms and exercise tolerance in medically treated patients with persistent, moderate to severe symptoms of HF; poor left ventricular (LV) function; and intraventricular conduction delay. The relatively few scenarios in which this modality has been studied make it possible to argue both for broadening and restricting the use of these devices until further trials are conducted. Here we review the proposed mechanisms of action, potential applicability, and cost impact of CRT of appropriately selected patients.