Oral Abstract Session
SCMR 22nd Annual Scientific Sessions
Background: Left ventricular ejection fraction (LVEF) is the preferred clinical marker of myocardial function and a predictor of recurrent cardiovascular events following acute myocardial infarction (AMI). However, LVEF is mainly determined by systolic function while not adequately reflecting other components of cardiac contractility and has, therefore, major limitations as a stand-alone prognostic marker for post-infarction outcome. Measurement of left ventricular myocardial dyssynchrony may improve risk assessment after AMI, which was subject of the present study.
Methods: A total of 1034 consecutive patients with AMI (STEMI: n=731; NSTEMI: n=303) undergoing cardiac magnetic resonance (CMR) imaging in median 3 days after infarction were included in this multicenter study. Circumferential and radial uniformity ratio estimates (CURE and RURE) were derived from CMR feature-tracking as markers of dyssynchrony (values between 0 and 1 with 1 reflecting perfect synchrony). The clinical study endpoint was the 12-month rate of major adverse cardiac events (MACE), consisting of all-cause death, re-infarction, and new congestive heart failure.
Patients with MACE had significantly impaired dyssynchrony estimates (p<0.001 for CURE and RURE compared to patients without events). Stratification according to median CURE (0.84) and RURE (0.75) resulted in significantly increased 12-month MACE rates in AMI patients with uniformity ratio estimates below median (p=0.001 in log-rank testing for all). In post-infarction patients with a LVEF >35% (n=918), CURE was identified as an independent predictor of outcome even after adjustment for established prognostic markers (p=0.011 in stepwise multivariate Cox regression analysis) while LVEF was not associated with adverse events in this subgroup of AMI patients.
Conclusion: Left ventricular myocardial dyssynchrony is a novel marker for optimized risk assessment after AMI and provides incremental prognostic information particularly in patients with preserved or only moderately reduced LVEF.