PATHOLOGIC CHANGES IN AURICULAR FIBRILLATION AND IN ALLIED ARRHYTHMIAS

From time to time during the past twenty years studies have been made to determine the existence of a specific lesion in auricular fibrillation, auricular flutter and paroxysmal tachycardia. The experiments of Mines and of Garrey demonstrated the possibility of a circus wave of contraction in animal tissues, and those of Lewis showed definitely that circus movement is the mechanism of auricular fibrillation and flutter and possibly of paroxysmal tachycardia. Previous to the time of these experiments, pathologists were prone to consider lesions in or around the sino-auricular and auriculoventricular nodes as of great importance in these arrhythmias, and especially in auricular fibrillation. Recently, little in the way of microscopic study has been done in this field, but the consensus of opinion seems to be that there is no specific pathologic picture. From the standpoint of the new physiology, no visible organic disease is necessary, and the facts that auricular