Control of sudden recurrent arrhythmic deaths: role of amiodarone

Patients resuscitated after out-of-hospital cardiac arrest have electrical instability of the myocardium, with 30% to 40% propensity for recurrent arrest in the first year. About 85% to 90% of such patients have complex ventricular ectopy and runs of ventricular tachycardia; in 70% to 80%, ventricular tachycardia or fibrillation are inducible by programmed electrical stimulation. The attempt to control recurrent cardiac arrest using these parameters and conventional antiarrhythmic drugs has yielded conflicting or variable results. Amiodarone was therefore studied in 40 consecutive patients (with previous cardiac arrests) in whom conventional antiarrhythmic therapy had proved ineffective or was not tolerated. The mean ejection fraction of the group was 0.29 +/- 0.12. At a mean follow-up of 16 months (range 5 to 40 months) six patients had died, three from heart failure, one from liver failure (not drug induced), and two from sudden (presumably arrhythmic) death. Late occurrences of arrhythmia were found in two patients (complicated by digitalis intoxication in one). Ambulatory ECG recordings showed that amiodarone had a potent suppressant effect on ventricular ectopy and runs of VT, but electrophysiologic studies demonstrated that it did not inhibit inducible VT/VF in greater than 65% despite an excellent clinical outcome. Limiting adverse reaction was seen in only one patient; other relatively minor side effects occurred in 10% to 15% of patients receiving maintenance therapy. Our data provide further evidence for the effectiveness of amiodarone in life-threatening ventricular arrhythmias, with a potential for the prolongation of survival in patients resuscitated after out-of-hospital cardiac arrests.