MODIFICATIONS IN THE EVOLUTION OF THE DOMINANT FREQUENCY IN VENTRICULAR-FIBRILLATION INDUCED BY AMIODARONE, DILTIAZEM, AND FLECAINIDE

In 22 anesthetized mongrel dogs, spectral methods were used to analyze the surface electrocardiogram (EGG) for the time course of the domina nt frequency in ventricular fibrillation and its modifications under t he influence of amiodarone, diltiazem, and flecainide. The ECG was rec orded over 5 minutes after triggering ventricular fibrillation. Follow ing AID conversion and by applying the Fourier fast transform, the fre quency spectrum oi the signals was obtained. In group 1 (5 dogs), the ECGs were obtained without prior drug administration; group 2 (5 dogs) first received amiodarone, 5 mg/kg; group 3 (7 dogs) received diltiaz em, 0.2 mg/kg; and group 3 (5 dogs) received flecainide, 2 mg/kg. All drugs were administered intravenously. An initial increase in the domi nant frequency of ventricular fibrillation was found in the control gr oup and also in the groups that received amiodarone, diltiazem, or fle cainide. Diltiazem significantly increased the dominant frequency and diminished the arrhythmia-slowing process. Amiodarone and flecainide t ended to diminish the dominant frequency.