From time to time, patients are encountered who display auricular fibrillation, either permanent or intermittent, as the sole evidence of disturbance of the heart. The frequent association of auricular fibrillation with obviously serious heart disease leads many physicians to consider this arrhythmia with gravity at all times and under all circumstances. Orgain and his co-workers1 in 1936 called attention to the favorable prognosis associated with cases of uncomplicated or idiopathic auricular fibrillation. It is not our intention to cover the literature in this paper, for this was adequately done by Brill2 in 1937.
Realizing the importance of acquiring further data on this subject in order to permit the segregation of the significant from the nonsignificant cases of auricular fibrillation, we have reinvestigated this subject with special reference to the clinical course of patients who exhibit auricular fibrillation in the absence of demonstrable evidence of organic heart disease and