Profound differences in prognostic impact of left ventricular reverse remodeling after cardiac resynchronization therapy relate to heart failure etiology.

Background: An ischemic etiology of heart failure (HF) has been associated with reduced left ventricular reverse remodeling after cardiac resynchronization therapy (CRT).
Objective: The purpose of this study was to assess the relationship between the etiology of HF and reverse remodeling and outcome after CRT.
Methods: Consecutive patients undergoing CRT implantation between October 1, 2008 and August 14, 2015 were retrospectively evaluated. Coronary angiography classified ischemic vs nonischemic etiology. Reverse remodeling was defined as the changes in left ventricular ejection fraction (LVEF) after 6 months. Clinical outcome was assessed 1 year after implantation using a combined end point of all-cause mortality and HF readmission.
Results: A total of 685 patients were included (300/385 for ischemic/nonischemic etiology). Compared with patients with ischemic cardiomyopathy, patients with nonischemic cardiomyopathy exhibited a greater degree of improvement in LVEF (8.4% ± 10.4% vs 15.8% ± 12.3%; P < .001). After correcting for differences, an ischemic etiology of HF predicted less reverse remodeling (P < .001) and a higher rate of mortality or HF readmission (hazard ratio 1.63; 95% confidence interval [CI] 1.12-2.73; P = .011). Nevertheless, in comparison to a greater degree of improvement in LVEF, a lesser degree of improvement in LVEF (0%-5%) was associated with a higher risk of all-cause mortality and HF hospitalization in patients with nonischemic cardiomyopathy (odds ratio 9.78; 95% CI 1.95-49.04; P = .006) but not in patients with ischemic cardiomyopathy (odds ratio 3.58; 95% CI 0.85-15.18; P = .083). The most accurate cutoff for improvement in LVEF predicting good clinical outcome was 5.5% in ischemic cardiomyopathy vs 10.5% in nonischemic cardiomyopathy.
Conclusion: CRT results in reverse remodeling in both patients with ischemic and nonischemic cardiomyopathy, but to a lesser extent in the former. Patients with an ischemic etiology are at an intrinsically higher risk of mortality and HF hospitalization, but derive benefit on outcome at a lesser degree of reverse remodeling.
(Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)