Ineffectiveness of quinidine in preventing atrial fibrillation following mitral valvotomy

One hundred patients in sinus rhythm who underwent closed mitral commissurotomy were divided alternately into two comparable groups. One group received prophylactic treatment with quinidine immediately after operation for a period of 10 days. The incidence of atrial fibrillation was 16% in both the treated and the untreated groups. In patients more than 40 years of age, the incidence of postoperative atrial fibrillation was much higher (48%). However, in these older, more vulnerable patients quinidine prophylaxis was no more effective than it was in the younger age groups. The only operative death in the entire series occurred in the treated group and could have been due to quinidine. In this controlled, prospective study the use of quinidine in moderate dosage was ineffective in preventing postoperative atrial fibrillation following mitral commissurotomy. Its routine use is not recommended.