Ventricular Fibrillation and Ion Transport

Ventricular fibrillation has been studied by driving the ventricles of the isolated rabbit heart electrically and observing whether fibrillation persisted after stimulation was stopped. The hearts were perfused by solutions of different ionic composition and the proportion of hearts in which persistent fibrillation was seen was determined for each solution. The proportion was controlled from 0 to 100 per cent according to the amount of K + , hearts fibrillating spontaneously in .25 N K + . A similar study was made by varying Ca ++ . Fibrillation was arrested by ATP and prolonged by dinitrophenol. Fibrillating hearts lost more K + than when they were not fibrillating. Fibrillation appeared to depend on disturbances of the metabolic processes concerned with ion movements.