Management of refractory sustained ventricular tachycardia with amiodarone: A reappraisal

Abstract

We examined the value of clinical variables, chronic 24-hour ambulatory ECG monitoring, and chronic electrophysiologic (EP) testing in 49 patients with recurrent and refractory sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) treated with chronic oral amiodarone in order to develop a prospective approach to the management of these patients. All patients underwent control EP studies followed by continuous telemetric cardiac monitoring during oral amiodarone administration (mean duration 29 ± 6 days, mean dose 739 ± 230 mg). Follow-up 24-hour ambulatory ECG monitoring and EP studies were performed. Thirty VT recurrences occurred in the first 4 weeks of amiodarone therapy (total incidence, 61%), with the majority (55%) in the first 3 weeks of treatment. During long-term follow-up (1 to 42, mean 15 ± 12 months), there were 12 symptomatic VT VF recurrences (incidence 24%). There was a higher incidence of VT recurrences if patients had inducible sustained or nonsustained VT at chronic EP study ( p < 0.01), or complex ventricular arrhythmias on ambulatory ECG monitoring ( p < 0.05). The sensitivity, specificity, and predictive accuracy of chronic EP testing and 24-hour ambulatory ECG monitoring were 100%, 35%, and 51%, and 58%, 84%, and 78%, respectively. Chronic EP testing correctly identified all patients who had their arrhythmia suppressed by amiodarone on long-term follow-up, while 42% of all VT recurrences occurred in patients without complex ventricular arrhythmias on 24-hour ambulatory ECG monitor. A prospective combined EP-ambulatory ECG approach to the management of patients with recurrent sustained VT VF on amiodarone is proposed, with the EP technique being used as the end point for efficacy and the ambulatory ECG technique being employed to identify early therapeutic failures. Alternative or adjunctive antiarrhythmic therapy is warranted for patients with inducible VT on chronic amiodarone therapy.