Retrospective study of the incidence of atrial fibrillation (AF) in 841 consecutive patients who had selective coronary arteriography and left ventricular catheterization from January 1, 1966 to December 31, 1976 was undertaken. There were 496 patients with coronary artery disease (CAD), 138 with valvular disease or cardiomyopathy, and 207 were normal. Chronic atrial fibrillation was present in 45 patients, of whom 35 has valvular disease or cardiomyopathy. One had coronary artery disease and 9 were normal. Chronic atrial fibrillation in coronary artery disease was rarely found.