Cardioversion and Digitalis

The electrocardiograms before and immediately after cardioversion of 100 consecutive patients with chronic atrial fibrillation treated at the Peter Bent Brigham Hospital have been analyzed. Evidence of digitalis intoxication in the precardioversion tracing was associated with a significant increase in the incidence of serious ventricular ectopic activity following electrical shock. The role of digitalis in post-cardioversion arrhythmias is reviewed. The measures to reduce the incidence and gravity of such arrhythmias are outlined.