Cardiac resynchronization therapy in asymptomatic or mildly symptomatic heart failure patients in relation to etiology: results from the REVERSE (REsynchronization reVErses Remodeling in Systolic Left vEntricular Dysfunction) study.

OBJECTIVES The purpose of this study was to determine the effects of cardiac resynchronization therapy (CRT) with respect to heart failure etiology among patients in the REVERSE (REsynchronization reVErses Remodeling in Systolic Left vEntricular Dysfunction) study. BACKGROUND CRT improves outcomes in New York Heart Association functional class III/IV heart failure with wide QRS with a more pronounced effect on left ventricular (LV) reverse remodeling in nonischemic patients. METHODS A total of 277 patients with nonischemic heart disease (IHD) and 333 with IHD etiology in New York Heart Association functional class I or II with QRS ≥120 ms and left ventricular ejection fraction ≤40% received a CRT (± implantable cardioverter-defibrillator) and were randomized to CRT-ON or CRT-OFF for 12 months. The primary end point was the percentage of patients worsened by the HF clinical composite response, and multiple prespecified secondary end points were evaluated regarding etiology using univariable and multivariable analysis. RESULTS At baseline, IHD patients were significantly older and had more comorbidities and less dyssynchrony than non-IHD patients. In non-IHD patients, 10% worsened in CRT-ON compared with 19% in CRT-OFF (p = 0.01). In IHD patients, 20% worsened in the CRT-ON compared with 24% in the CRT-OFF group (p = 0.10). Non-IHD patients assigned to CRT-ON improved more in left ventricular end-systolic volume index than IHD patients. Randomization to CRT, left bundle branch block, and wider QRS duration independently predicted response to both end points, whereas non-IHD etiology was an independent predictor only for left ventricular end-systolic volume index. CONCLUSIONS This substudy of REVERSE shows that CRT reverses left ventricular remodeling with a more extensive effect on nonischemic patients. Etiology was, however, not an independent predictor of clinical response. (REsynchronization reVErses Remodeling in Systolic Left vEntricular Dysfunction [REVERSE]; NCT00271154).