Electroversion of lone atrial fibrillation and flutter including haemodynamic studies at rest and on exercise.

Thirty patients with atrial fibrillation and seven with atrial flutter, all of whom were carefully examined to exclude any associated underlying heart disease, were treated by direct current shock. Sinus rhythm was achieved in 24 of the 30 patients with atrial fibrillation; all patients with atrialflutter were brought into sinus rhythm. The incidence of complications was particularly high in those with lone atrial fibrillation and could be related to the higher energy level setting required. No complications occurred in the group treatedfor lone atrialflutter in whom low energy level settings were uniformly successful. Only 4 patients treatedfor atrialfibrillation remained in sinus rhythm at the end of a 36-month follow-up. Reversion to the dysrhythmia occurred z within minutes or days of electroversion and the majority who reverted did so within the first month. Quinidine was of little use in maintaining sinus rhythm. In contrast, patients with lone atrialflutter maintained sinus rhythm for a significantly longer period of time.