EP News: Allied Professionals

Abstract

In this report by Ruwald et al (Circulation 2014; PMID 25301831), 752 Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy (MADIT-CRT) patients who were randomized to cardiac resynchronization therapy–defibrillator (CRT-D) and who also had echocardiograms at baseline and 12 months were studied for an average of 22 months after the second echocardiogram to assess outcome (ventricular arrhythmias [VAs], heart failure [HF], death, and inappropriate implantable cardioverter-defibrillator [ICD] therapy). Patients were grouped on the basis of their left ventricular ejection fraction (LVEF) on the 12-month echocardiogram: ≤35%, 36%–50% (“subnormalization”), and >50% (“normalization”). The authors found that 7.3% of patients normalized their LVEF and 79% obtained an LVEF of 36%–50%. Those with normalization and subnormalization had reduced risk of VAs, HF, and death as compared with those with LVEF ≤35%. Only 3 patients with normal LVEF had VAs, and none were shocked by the ICD. Factors associated with normalization include female sex, left bundle branch block, non–ischemic cardiomyopathy, baseline LVEF >30%, and baseline small left atrial and left ventricular chamber sizes. Of the 42 patients who had all these 6 variables and LVEF normalization, none had VAs. There was continued risk of inappropriate ICD therapy even in those with normal EF. The authors conclude that in patients treated with CRT-D who normalize their LVEF, the outcome is very good with a low risk of VAs and downgrade from CRT-D to CRT-pacemaker could be considered at generator replacement, especially in those with all 6 favorable characteristics at baseline and no VAs before implantation or during follow-up.