Early Reperfusion Therapy Affects Inducibility, Cycle Length and Occurrence of Ventricular Tachycardia Late After Myocardial Infarction

Abstract

BACKGROUND: -This study aimed to evaluate the impact of early reperfusion during acute myocardial infarction (MI) on ventricular tachycardia (VT) inducibility, inducible VT cycle length (CL) and occurrence of spontaneous VT late after MI. METHODS AND RESULTS: -Five-hundred-six patients (440 male, 63±11yr) with prior MI who underwent electrophysiology study before implantation of an implantable cardioverter defibrillator for primary or secondary prevention were assessed. Patients were classified according to the reperfusion strategy {reperfusion (thrombolysis (n=44) or percutaneous coronary intervention (n=65)) vs. no reperfusion (n=397)} during acute MI. Monomorphic sustained VT was inducible in 351 (69%) patients. Inducibility in reperfused and non-reperfused patients was similar in primary prevention patients (56% vs.58%) but significantly higher for non-reperfused patients in secondary prevention patients (56% vs.79%, p=0.001). Induced VTCL was shorter (247±40 vs.287±63, p<0.001) and very fast VT (CL≤250 ms) was more often induced in reperfused patients (71% vs.47%, p=0.001). In primary prevention patients, non-reperfusion was associated with a doubled risk for first spontaneous VT during follow-up. CONCLUSIONS: -There are important differences in VT inducibility, induced VTCL and occurrence of spontaneous VT in the chronic infarct healing phase between patients with and without successful reperfusion during acute MI. These findings suggest differences in the chronic arrhythmogenic substrate.