Abstract 2363: Antiarrhythmic Drug Therapy for Sustained Ventricular Arrhythmias Complicating Acute Myocardial Infarction
Background: There are few data to guide antiarrhythmic drug therapy for sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) in the setting of an acute myocardial infarction (AMI).
Methods: We conducted a retrospective analysis of patients with ST-segment elevation MI. complicated by sustained VT/VF in the GUSTO IIB and GUSTO III trials. All-cause death was compared in patients treated with amiodarone, lidocaine, or no antiarrhythmic therapy. We used Cox proportional hazards modeling and inverse weighted estimators to adjust for baseline characteristics, beta-blocker use, and the propensity to receive antiarrhythmic drug therapy. Due to differences in the proportional hazard for death in early follow-up (0 to 3 hours after sustained VT/VF), we analyzed all-cause mortality using time-specific hazards.
Results: Among the 27,201 patients enrolled in GUSTO IIB and GUSTO III, 1126 (4.1%) developed sustained VT/VF. Patients were treated with lidocaine (n=664, 59.0%), amiodarone (n=50, 4.4%), both (n=110, 9.7%), or no antiarrhythmic drug therapy (n=302, 26.8%). In the first 3 hours after the arrhythmia, both amiodarone (adjusted HR 0.58, 95% CI 0.39 – 0.87) and lidocaine (adjusted HR 0.78 [0.62–1.00]) were associated with a lower hazard of death - likely evidence of survivor bias rather than treatment differences. Among patients who survived 3 hours, amdiodarone was associated with increased mortality at 30 days (HR 1.67 [1.14–2.47]) and 6 months (adjusted HR 1.91 [1.33–2.76]) but lidocaine was not (adjusted HR 1.16 [0.80–1.68] at 30 days) and (adjusted HR 1.08 [0.75–1.54] at 6 months).
Conclusion: Among patients with AMI complicated by sustained VT/VF who survive 3 hours, amiodarone, but not lidocaine is associated with an increased risk of death. These findings reinforce the need for randomized controlled clinical trials of antiarrhythmic drug therapy for sustained VT/VF complicating AMI.