Electrically Induced Ventricular Fibrillation.

Abstract

METHODS:

Cats of either sex weighing 1 . 6— 3.0 were anaesthetized with pentobarbitone sodium (30 mg/Kg intrathoracically, upper right diap hragmatic area using a fine short needle). The trachea was cannulated to facilitate spon taneous and artificial respiration when required.  The voltage necessary to indute fibrillation varied between animals. If fibrillation could not be induced at certain• voltage3 the stniulus voltage was increased until the .condition. appeard. After each stimulation period, the prepararjon was left for 10 minutes to reestablish as nearly as possible preufibrillatory condition. The control or thres hold iibrillatory voltage was established three times in each animal.

RES ULTS:

The control voltage necessary to induce VF ranged from 1OV-3OV in these experiments. The effects of drugs on the ventricular fibrillating threshold (V.F.T.) have been described in detail elsewhere (Rashid, 1976).  Similarly no changes in heart rate (H.R.) or left ventricular contractility (L.V.C.) were observed. Cardiac Output guide (C.O.) slightly decreased ( 5%) though not significantly from the control data while cardiac effort index (C.E.I.) was unchaed.

DISCUSSION:
Electrical stimulation of the myocardium and the subsequent achievement of VF can be performed by two methods.As it has been shown that no adverse effects were seen, on the general haemodynamics 25 minutes after repeated intermittent episodes of electrical stimulation, the true cardiovascular effect of a drug compound can be seen and if a drug can be shown to have no pdverse effect on general haernodynamic function. and is also capable of raising V.F.T., it is possible that this drug may be useful for antidysrhthmic purposes.