LONE AURICULAR FIBRILLATION

Abstract

Mitral stenosis, thyroid toxemia, cardiac infarction, constrictive pericarditis, and hypertension are among the common causes of auricular fibrillation. Occasionally, however, the arrhythmia is discovered fortuitously and subsequent investigation shows that structural heart disease is absent. The condition has been described. variously as benign, idiopathic, arteriosclerotic, functional, and senile fibrillation, fibrillation of unknown origin and fibrillation without heart disease. We have proposed for it the term lone auricularfibrillation. Twenty patients were selected for an analysis of the special features that characterize lone fibrillation. Apart from taking each patient's history and recording the findings of a routine clinical examination, special tests were made when necessary to exclude heart disease of any kind. An electrocardiogram was always taken, not so much to confirm the nature of the arrhythmia as to show the absence of preponderance of either ventricle and of cardiac infarction. Once, the basal metabolic rate was estimated and a radio-active iodine test used to exclude thyroid toxemia. A phonocardiogram was recorded in most of the patients to prove the absence of murmurs and added sounds, especially the mitral snap, even though they had been inaudible. Cardioscopy was carried out in each case to ensure the absence of cardiac enlargement from any source, and par-