[Prediction of long-term efficacy of amiodarone for refractory ventricular tachycardia: clinical significance of electrophysiologic study and Holter monitoring].

The usefulness of electrophysiologic study and Holter monitoring for predicting the long-term efficacy of amiodarone was investigated in 31 patients with sustained ventricular tachycardia (VT) and organic heart disease. Patients underwent both electrophysiologic study and Holter monitoring before and during oral administration of amiodarone. These patients were followed up and the difference in the prognosis according to the results of these two tests was examined. During a follow-up period of 887 +/- 678 days, sustained VT recurred in 13 patients and sudden cardiac death in 3. Sustained VT recurred in only one of 11 patients in whom amiodarone was determined effective by electrophysiologic study whereas recurrent VT and/or sudden death occurred in 15 of 20 patients in whom amiodarone was determined ineffective (p < 0.01). Eight of 18 patients in whom amiodarone was determined effective by Holter monitoring, and 8 of 13 in whom it was determined ineffective, suffered recurrent VT and/or sudden cardiac death. Amiodarone was judged effective in 7 patients by both tests (group I) and in 15 by either electrophysiologic study or Holter monitoring (group II). In the remaining nine patients, amiodarone was ineffective by both tests (group III). Recurrent VT or sudden death occurred in none of the patients in group I (0%), in nine group II (60%) and seven in group III (78%). The prognoses of the three groups were significantly different: group I vs II; p < 0.05, group II vs III: p < 0.05, and group I vs III; p < 0.005. The combination of the two drug tests, electrophysiologic study and Holter monitoring, is a useful method for the prediction of the long-term efficacy of amiodarone in patients with sustained VT and underlying heart disease. Patients in whom amiodarone was determined ineffective in both tests, are at high risk for VT recurrence and sudden death, and interventional therapy is recommended.