The reported long-term efficacy and safety of amiodarone varies considerably. Further, the role of electrophys ologic drug testing of amiodarone therapy is controversial. In this study, 71 patients with drug-refractory, recurrent sustained ventricular tachycardia were treated with amiodarone and were followed over 20 ± 17 months. Amiodarone had to be discontinued prior to discharge in 6 of the 71 patients because of suspected proarrhythmic actions or side effects. Of the remaining 65 patients started on long-term amiodarone, 21 (32%) had recurrence of ventricular tachycardia and 13 (20%) died suddenly. Of the 21 patients with recurrence of ventricular tachycardia while receiving amiodarone, 15 remained on amiodarone, with or without a therapy modification; the remaining six required drug discontinuation. By actuarial analysis, 57 ± 6% of patients will be able to continue amiodarone, with or without a therapy modification for 2 years and 36 ± 7% will have successful long-term therapy without a recurrence of VT or intolerable side effects for 2 years. Of 63 patients with control electrophysiologic studies, 36 had repeat programmed stimulation after 3 weeks of amiodarone therapy. By chi square and logistic regression analyses, the mode of induction of ventricular tachycardia with amiodarone was useful in predicting long-term outcome. Patients with a more easily induced ventricular tachycardia after amiodarone (compared to control studies) were at higher risk of ventricular tachycardia recurrence or sudden death, whereas patients with a ventricular tachycardia that was more difficult to induce tended to have successful long-term therapy. In summary, a subset of patients with drug-refractory ventricular tachycardia can be successfully treated with amiodarone although therapy modifications are often required. The mode of ventricular tachycardia induction with amiodarone therapy may be helpful in predicting which patients are more likely to have successful long-term therapy and which patients may require therapy modification or other treatments. Repeat electrophysiologic studies after several weeks of amiodarone therapy can be useful in guiding therapy decisions in patients with recurrent ventricular tachycardia.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine