Residual flow to the infarct zone against lethal ventricular tachyarrhythmias during the acute phase of myocardial infarction

Background: The benefits of residual flow to the infarct zone have been demonstrated in acute myocardial infarction (AMI), but its relation to ventricular tachyarrhythmias remains uncertain. Hypothesis: This study was undertaken to test the hypothesis that residual flow is an important determinant of lethal ventricular tachyarrhythmias (sustained ventricular tachycardia or ventricular fibrillation) during the acute phase of AMI. Methods: We investigated the determinants of lethal ventricular tachyarrhythmias within 24 h after the onset of symptoms in 310 consecutive patients (256 men; age 57.4 ± 11.5 years) with AMI undergoing primary angioplasty. Patients were divided into two groups: those with (Group 1, n = 40) and those without (Group 2, n = 270) lethal ventricular tachyarrythmias. Residual flow was defined as the presence of anterograde flow (≥Thrombolysis in Myocardial Infarction [TIMI] 2 flow) or good angiographic collaterals (≥ grade 2) on a preintervention angiogram. Results: Univariate determinants of lethal ventricular tachyarrhythmias were cardiogenic shock, systolic blood pressure, peak level of creatine kinase, culprit artery, spontaneous reperfusion, and residual flow. In multivariate analysis, however, cardiogenic shock (odds ratio [OR] = 4.79, 95% confidence interval [CI] 1.63-14.11, p = 0.004), residual flow (OR = 0.34, 95% CI 0.14-0.81, p = 0.015), and the right coronary artery as the culprit artery (OR = 2.09, 95% CI 1.03-4.22, p = 0.040) were independent determinants of these arrhythmias. In-hospital death occurred in 10 patients and was more common in Group 1 than in Group 2 (12.5% vs. 1.9%, respectively, p < 0.001). Conclusion: The absence of residual flow was associated with greater risk of lethal ventricular tachyarrhythmias during the acute phase of AMI, suggesting a protective role of residual flow against these arrhythmias in AMI.