Infarct Tissue Heterogeneity by Contrast-Enhanced Magnetic Resonance Imaging Is A Novel Predictor of Mortality in Patients With Chronic Coronary Artery Disease and Left Ventricular Dysfunction Watanabe/Abbasi et al: PIZ and Mortality in CAD

Background—Strategies for prevention of sudden cardiac death (SCD) focus on severe left ventricular (LV) dysfunction, though most SCD post-myocardial infarction occurs in patients with mild/moderate LV dysfunction. We tested the hypothesis that infarct heterogeneity by cardiac magnetic resonance (CMR) is associated with mortality beyond left ventricular ejection fraction (LVEF) in patients with coronary artery disease (CAD) and LV dysfunction. In addition, we examined the association between infarct heterogeneity and mortality in those with LVEF>35%. Methods and Results—We studied 301 patients with CAD and LV dysfunction referred for CMR. We quantified total infarct mass, infarct core mass, and peri-infarct zone normalized for total infarct mass (%PIZ) using signal-intensity criteria of >2SDs, >3SDs, and 2-to-3SDs above remote myocardium, respectively. Mean LVEF was 41±14%. After 3.9 years median follow-up, 66 (22%) patients died (13 SCD; 33 with LVEF>35%). In patients with LVEF >35%, belowmedian %PIZ carried an annual death rate of 2.8% versus 12% in patients with abovemedian %PIZ (p<0.001). In a multivariable model, %PIZ maintained strong association with mortality adjusted to patient age, LVEF, RVEF, prolonged QT interval, and total infarct size and resulted in improve risk reclassification 0.492 [95% CI 0.183-0.817]. Conclusions—CMR infarct heterogeneity has a strong association with mortality independent of LVEF in patients with CAD and LV dysfunction, particularly in patients with mild or moderate LV dysfunction. Further studies incorporating CMR in clinical decision-making for defibrillator therapy are warranted.