Intravenous amiodarone for the pharmacological termination of haemodynamically-tolerated sustained ventricular tachycardia: is bolus dose amiodarone an appropriate first-line treatment?

OBJECTIVE: To examine the efficacy of bolus dose intravenous amiodarone for the pharmacological termination of haemodynamically-tolerated sustained monomorphic ventricular tachycardia (VT).

DESIGN, SETTING AND PARTICIPANTS: Retrospective case series of consecutive emergency admissions with haemodynamically-tolerated sustained monomorphic VT administered bolus dose intravenous amiodarone 300 mg, according to current UK advanced life support practice guidelines.

MAIN OUTCOME MEASURES: Pharmacological termination rates within 20 min and 1 h and incidence of hypotension requiring emergency direct current cardioversion (DCCV) during this period.

RESULTS: 41 patients (35 men) of mean (SD) age 68 (10) years, the majority (85%) with ischaemic heart disease and impaired left ventricular function (mean (SD) ejection fraction 0.31 (0.11)), were enrolled in the study. The median VT duration was 70 min (range 15-6000), mean heart rate was 174 (34) bpm and systolic and diastolic blood pressures were 112 (22) and 73 (19) mm Hg, respectively. Pharmacological VT termination occurred within 20 min in 6/41 patients (15%; 95% CI 7% to 29%) and within 1 h in 12/41 patients (29%; 95% CI 18% to 45%). Haemodynamic deterioration requiring emergency DCCV occurred in 7/41 patients (17%; 95% CI 8% to 32%).

CONCLUSIONS: Although advocated by advanced life support guidelines, bolus dose intravenous amiodarone was relatively ineffective for acutely terminating haemodynamically-tolerated sustained monomorphic VT with a significant incidence of haemodynamic destabilisation requiring emergency DCCV. Previous studies in the identical clinical setting suggest that alternative antiarrhythmic agents, particularly intravenous procainamide and sotalol, may be superior. A prospective randomised trial is required to determine the optimal drug treatment for stable sustained monomorphic VT in the emergency setting.