Cardiac Resynchronization Therapy and Implantable Cardiac Defibrillators in Left Ventricular Systolic Dysfunction. Evidence Report/Technology Assessment Number 152

摘要

Cardiac resynchronization therapy (CRT) refers to atrial-synchronized biventricular pacing (i.e., pacing the right atrium, right ventricle, and left ventricle). CRT improves the electrical dyssynchrony found in many patients with heart failure (HF) and thereby can improve mechanical dyssynchrony leading to increased left ventricular filling time, reduced mitral regurgitation, and reduced septal dyskinesis. Implantable cardioverter defibrillators (ICD) have at least one lead which resides in the right ventricle dedicated to pacing and/or defibrillating lethal cardiac arrhythmias. More advanced ICD (dual-chamber devices) have leads in the right atrium and right ventricle to help discriminate arrhythmic events and have the potential to be programmed to provide dual chamber pacing (e.g., DDD pacing mode). Although earlier systematic reviews of CRT and ICD did report benefits from both therapies when evaluated individually in patients with HF, questions remained. For one, as these earlier systematic reviews focused on randomized efficacy trials, the generalizability of their results to clinical practice were uncertain (particularly with respect to potential adverse effects). Second, neither of the earlier reviews (which focused on individual devices) was able to clarify the incremental benefits conferred by combined CRT-ICD devices over CRT alone or ICD alone devices, nor were these earlier reviews able to define which patient groups would benefit most from which devices. Finally, a number of large trials have been published since the earlier systematic reviews were performed and their impact on the pooled evidence base required assessment.