Abstract 522: Predictors of Death and Life-threatening Ventricular Tachyarrhythmias in Patients With Previous Myocardial Infarction by Left Ventricular Longitudinal Strain Analysis
Background: Impaired left ventricular (LV) ejection fraction (EF) is an important clinical criterion for insertion of implantable cardioverter-defibrillators (ICD) in patients with previous myocardial infarctions (MI). This study aims to further risk stratify patients using segmental longitudinal strains in the infarct, peri-infarct and remote LV zones.
Methods: 2-dimensional speckle tracking longitudinal strain analyses were performed in 415 patients with previous MI and ICD implantation for primary prevention. Infarct segment was defined as longitudinal strain >−5%; peri-infarct segment was immediately adjacent to an infarct segment; remote segment was any segment not an infarct or peri-infarct segment. Clinical, ECG and biochemical variables including glomerular filtration rate (GFR) were recorded in all patients. Primary endpoint was all-cause mortality and secondary endpoint was occurrence of life-threatening ventricular tachyarrhythmias treated with appropriate ICD therapy.
Results: Mean age was 67±10yrs, 367 men. 258 (62%) patients had cardiac resynchronization therapy (CRT). Mean LVEF was 26±7%. Mean longitudinal strains of the infarct, peri-infarct and remote zones were −1.0±2.6%, −10.3±2.0%, and −13.0±3.4% respectively. After a mean follow-up period of 29±19 months, 83 (20%) patients died. Mean longitudinal strain in the peri-infarct zone was more impaired in patients who died compared to others (−9.4±1.7 vs. −10.3±2.1%, p<0.001). Only mean longitudinal strain in the peri-infarct zone (HR 1.21, 95% CI 1.07–1.37, p=0.002), NYHA functional class (HR 1.23, 95% CI 1.00 –1.51, p=0.047) and GFR (HR 0.99, 95% CI 0.98 –1.00, p=0.018) were independent predictors of death on Cox regression analysis. Similarly, 95 (23%) patients experienced life-threatening ventricular tachyarrhythmias during follow-up. Only mean longitudinal strain in the peri-infarct zone (HR 1.20, 95% CI 1.07–1.33, p=0.001) independently predicted ventricular tachyarrhythmias on Cox regression analysis.
Conclusions: Longitudinal strain of the peri-infarct zone may be a useful risk stratification parameter for patients with previous MI who are candidates for ICD implantation for primary prevention.