A review of direct current cardioversions for atrial arrhythmia

The risk of arterial embolism is well recognised following Direct Current Cardioversion (DCC) for atrial fibrillation although the use of prophylactic anticoagulation remains controversial.

To determine the risk of arterial embolism post-cardioversion and which factors predict successful cardioversion and maintenance of sinus rhythm.

A retrospective study was carried out of all cardioversions performed for atrial fibrillation and atrial flutter at the Waveney Hospital Ballymena, during 1989-1993. A review of medical records and electrocardiograms was carried out to assess demographic characteristics, co-existent diseases, anticoagulant status, echocardiographic features and characteristics of the arrhythmia. Embolic events in the six weeks post-cardioversion were noted.

The study included 157 cardioversions in 109 patients. The predominant arrhythmia was atrial fibrillation (n = 108, 69%). Three of 109 patients (2.7%) experienced embolic complications, none of whom had anticoagulation prior to the procedure. No risk factors for cerebro-vascular disease or significant valvular heart disease were present. Return to sinus rhythm was achieved in 143 (91%) procedures. Increasing coarseness of atrial fibrillation was associated with a non-significant trend towards successful restoration of sinus rhythm (p = 0.18). Recurrence of the original arrhythmia was predicted by an increase in coarseness of atrial fibrillation (p < 0.05).

These findings indicate that embolic complications can occur in patients undergoing DCC with normal echocardiographic dimensions, and that prophylactic anticoagulation should be considered in all patients. Coarseness of atrial fibrillation may be used as a guide to predict the chance of successful cardioversion and of the likelihood of maintaining sinus rhythm once this has been achieved.