Effect of atrial fibrillation on cardiac output.

The introduction by Lown, Amarasingham, and Neuman (1962) of a safe, simple, and effective method of converting atrial fibrillation to sinus rhythm has increased the interest in the effects of this arrhythmia on the circulation. Previous reports indicate scant agreement regarding the effects of atrial fibrillation on the cardiac output. Studies on groups of patients with and without atrial fibrillation have been associated with the difficulty of obtaining strictly comparable groups. Cardiac output studied on the same patients before and after drug conversions to sinus rhythm have been complicated by the effect on output of the drugs employed. The present study was undertaken to determine the changes, if any, on cardiac output when atrial fibrillation was removed by direct current conversion.