Predictors and implications of early left ventricular ejection fraction improvement in new-onset idiopathic nonischemic cardiomyopathy with narrow QRS complex: A NEOLITH substudy.

Abstract

Predictors and implications of early left ventricular ejection fraction (LVEF) improvement with guideline-directed medical therapy (GDMT) in new-onset idiopathic nonischemic cardiomyopathy (NICM) with narrow QRS complex are not well described. The objectives were to describe predictors of LVEF improvement after 3months on GDMT and adverse cardiac events based on post-GDMT LVEF status (≤35% vs. >35%). A retrospective cohort study was performed in subjects with new-onset NICM, LVEF ≤35%, and narrow QRS complex. Associations for baseline variables with post-GDMT LVEF improvement and absolute change in LVEF (∆LVEFGDMT ) were assessed. Cox proportional hazards models assessed associations for post-GDMT LVEF status with adverse cardiac events. In 70 subjects, 31 (44%) had post-GDMT LVEF ≤35% after a median follow-up time of 97.5days (interquartile range, 84-121days). In final multivariable models, severely dilated left ventricular end-diastolic diameter (LVEDD), compared with normal LVEDD, strongly predicted post-GDMT LVEF ≤35% (odds ratio, 7.77; 95% confidence interval [CI], 1.39-43.49; p=.02) and ∆LVEFGDMT (β=-15.709; standard error=4.622; p=.001). Subjects with post-GDMT LVEF ≤35% were more likely to have adverse cardiac events over a median follow-up time of 970.5days (unadjusted hazard ratio, 2.15; 95% CI, 0.93-4.96; p=.07). In the post-GDMT LVEF ≤35% group, 9 of 26 subjects (35%) had long-term LVEF>35%. In new-onset NICM with narrow QRS complex, nondilated LVEDD predicted early LVEF improvement. Those with post-GDMT LVEF ≤35% had higher risk of adverse cardiac events, but a substantial proportion demonstrated continued long-term LVEF improvement.