Resynchronization/defibrillation for ambulatory heart failure trial: rationale and trial design

Abstract

Purpose of review: This paper reviews the effect of cardiac resynchronization therapy (CRT) on patients with heart failure symptoms, in particular, in patients with mild symptoms of heart failure. It provides the rationale and design of a randomized controlled trial to determine if CRT, when added to implantable cardioverter defibrillator, will be beneficial in patients with left ventricular dysfunction, ventricular conduction delay and mild heart failure symptoms.

Recent findings: CRT has been demonstrated to improve functional capacity, quality of life, and reduce heart failure hospitalization in patients with advanced symptomatic heart failure, and evidence of a ventricular conduction abnormality on ECG. In patients with milder heart failure symptoms, three randomized controlled trials and observational studies failed to convincingly show improvement of functional status, but demonstrated improved ventricular reverse remodelling with more advanced heart failure patients.

Summary: Two large randomized clinical trials are currently ongoing (RAFT and MADIT-CRT). The results of these trials will determine the efficacy of CRT in patients with systolic heart failure, ventricular conduction abnormality and milder symptoms.