Prognostic Value of Cardiac‐MRI Scar Heterogeneity Combined With Left Ventricular Strain in Patients With Myocardial Infarction

BACKGROUND: Sudden cardiac death (SCD) after myocardial infarction (MI) is mostly caused by ventricular arrhythmias. As an arrhythmogenic substrate, infarct border zone (BZ) results in adverse electrophysiological properties. PURPOSE: To explore myocardial scar entropy (BZ, infarct core [IC], BZ + IC, expressed as IBZ) and to investigate their prognostic value combined with left ventricular (LV) strain parameters (global radial strain [GRS], global circumferential strain [GCS], global longitudinal strain [GLS]) in patients after MI. STUDY TYPE: Prospective. POPULATION: One hundred fifty-seven patients with previous MI, 26 in primary endpoint events group, 30 in secondary endpoint events group, and 43 in total endpoint events (primary + secondary). FIELD STRENGTH/SEQUENCE: 3.0 T/cine, late gadolinium enhancement (LGE). ASSESSMENT: Three-dimensional feature tracking analysis for three directions (radial, circumferential, and longitudinal), entropy and extent of infarct-related areas (BZ, IC, and IBZ), LV functional parameters. STATISTICAL TESTS: Student t-test, Mann-Whitney U, Spearman or Pearson rank correlation analysis, receiver operating characteristic curve, Kaplan-Meier event-free survival curve, and Cox proportional hazards regression were used. Results were considered statistically significant at P < 0.05. RESULTS: LGE extent and entropy of all infarct-related areas (BZ, IC, and IBZ) were significantly higher and GLS were lower in patients with endpoint events than those without. BZ and IBC entropy were further associated with LV strain in after-MI patients. In the univariable and multivariable Cox analysis, BZ entropy manifested independent association with primary endpoint events (hazard ratio: 3.859; 95% confidence interval: 2.136-6.974). Primary and secondary endpoint events prognostic value was improved by the addition of BZ entropy and GLS to the LVEF model (Delong test, Z = 2.729 for primary endpoint events; Z = 3.230 for secondary endpoint events). DATA CONCLUSION: Entropy of myocardial fibrosis was associated with LV strain. Assessment of BZ entropy and GLS improved prognostic value for endpoint events of LVEF. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 5.