Abstract 16750: Effectiveness of Intravenous Phenytoin as Adjuvant Antiarrhythmic Therapy to Suppress Incessant Ventricular Tachydysrhythmias and Ventricular Tachycardia Storm
Introduced as an antiarrhythmic drug four decades ago, the effectiveness of intravenous phenytoin in the management of incessant ventricular tachydysrhythmias (IVT) and ventricular tachycardia storm (VTS) has not been well described. Thus, we retrospectively reviewed the records of 48 consecutive patients (mean age - 67 years; 42 men, 6 women) with IVT or VTS who received a loading dose of phenytoin (500-100mg over 1-2 hours) adjunctively with other antiarrhythmic agents. After loading, oral phenytoin was given (100-300 mg/d) as needed. Thirty-five patients had an automatic cardioverter defibrillator (ICD) in place before IVT or VTS episode. Thirty-six patients had an ischemic cardiomyopathy, 11 of whom had a myocardial infarction on admission. Thirteen patients were status post recent cardiac surgery (8 coronary artery bypass, 3 valve replacement and 2 left ventricular assist devices). Twelve patients had a nonischemic cardiomyopathy (1 with cardiac sarcoidosis, 1 with hypertrophic cardiomyopathy and 10 with idiopathic cardiomyopathy). The mean left ventricular ejection fraction was 25%. Phenytoin was added to amiodarone in 42 patients (intravenous in 37 patients), 32 of whom were also receiving lidocaine or mexiletine. Of the remaining patients, one patient was receiving sotalol prior to phenytoin. Five others received sotalol along with additional antiarrhythmic agents prior to administration of intravenous phenytoin. Fourteen patients underwent catheter ablation procedures to treat ventricular tachycardia, 9 of which were performed after phenytoin was administered. Complete or marked suppression of IVT or VTS was noted within 6 hours in 24 patients and within 24 hours in 34 (71%) patients. All patients with nonischemic cardiomyopathy showed complete suppression at 6 hours of administration of phenytoin. Thirty-seven (77%) patients (21 IVT, 16 VTS) survived to hospital discharge, 24 of whom were discharged on oral phenytoin along with additional antiarrhythmic agents. In conclusion, administration of intravenous phenytoin, as adjuvant antiarrhythmic therapy, has substantial beneficial impact in the treatment of incessant ventricular tachydysrhythmias and ventricular tachycardia storm and may be life-saving.
- Arrhythmias, treatment of
- Ventricular arrhythmia
- Ventricular fibrillation
- Ventricular tachycardia
- © 2013 by American Heart Association, Inc.