Abstract #7758. Speckle Tracking Echocardiographic Assessment in Post-Myocardial Infarction Patients with Preserved or Slightly Depressed Left Ventricular Ejection Fraction and Ventricular Arrhythmias.

Introduction. Depressed left ventricular (LV) ejection fraction (EF) is currently the major indication for implantation of primary prevention implantable cardioverter-defibrillator (ICD) after myocardial infarction (MI). Because sudden cardiac death (SCD) also occurs in patients without a depressed EF, additional predictors are needed to identify patients at high risk for SCD after MI. A myocardial strain reduction by echocardiography can potentially be an indicator of regional dysfunctional myocardium. We hypothesized that electrical abnormalities in patients after MI will lead to LV mechanical dispersion, which can be measured as regional heterogeneity of contraction by myocardial strain. We aimed to compare myocardial strain data of patients with ischemic heart disease with and without ventricular arrhythmias (VAs) with preserved or slightly depressed LVEF. Methods. We enrolled 72 post-MI patients; 36 patients underwent ICD implantation due to prior history of sustained VAs and 36 patients were free of documented sustained VAs. Longitudinal, radial, and circumferential strain were measured by two-dimensional speckle tracking echocardiography (EchoPAC software, General Electrics, Fairfield, CT, USA). Global and segmental strain were obtained by averaging the maximum myocardial systolic shortening in a 16-segment LV model. Results. LVEF did not differ between groups (42.7±8.5 vs. 46.3±8.5, p=ns, respectively). Inferior wall MI was present in 47.2% vs. 33.3% of patients (p=ns, respectively). Global (-9.4±3.1 vs. -11.6±1.9, p=.011, respectively), and posterior wall circumferential strain (-4.9±2.5 vs. -8.8±2.7, p=.009, respectively) were significantly different between groups. ROC curves showed that the optimal cutoff value for posterior wall circumferential strain was -6.2 with a sensitivity of 67% and a specificity of 89% in predicting VAs. Conclusions. Global circumferential strain was a marker of VAs in post-MI patients with relatively preserved LV function. The posterior wall circumferential strain was reduced in patients with VAs. These novel parameters assessed by myocardial strain are independent of LVEF and may add important informations about the susceptibility for VAs and possibly SCD in survivors of MI.