Direct current cardioversion in digitalized patients with mitral valve disease

Thirty-two elective direct current cardioversions were performed in 23 digitalized patients with atrial fibrillation or flutter or both and predominant mitral stenosis who had undergone prior mitral commissurotomy. The immediate success rate was 94%, and 78% of the patients stayed in normal rhythm for at least four weeks after cardioversion. Postcardioversion ventricular arrhythmias occurred in 100% of group 1 patients with hypokalemia and in only 11.1% of group 2 patients without electrolyte imbalance, a significant difference (P<0.001). Congestive heart failure and long-term diuretic therapy, particularly with orally administered diuretics, were important factors predisposing to electrolyte imbalance. If hypokalemia is recognized and treated in the precardioversion period, maintenance digitalis therapy may be continued and cardioversion performed without increased risk of ventricular arrhythmias.