From delirium cordis to atrial fibrillation: historical development of a disease concept.

In 1874, the electrical stimulation of animal hearts made known the existence of atrial fibrillation, but atrial fibrillation was not associated with its clinical counterpart, arrhythmia perpetua, until 1909, by which time simultaneous recordings of the human heartbeat, the venous and arterial pulses, and electrocardiographic activity had revealed the common origin of these events. After the electrical basis of atrial fibrillation was found and after atrial fibrillation was clearly distinguished from ventricular fibrillation, investigation into its mechanism ensued. Two contrasting theories, that of circus movement and that of tachysystole from a single focus, led to 30 years of research and debate. Pivotal to the argument was the notion of blocked conduction. Although the theory of circus movement prevailed for a long time, it appeared to be demolished by electrophysiologic experiments done between 1948 and 1950. The realization that blocked conduction could later reenter led to more recent research in animals and humans that revived the notion of circular conduction, although in a much more sophisticated form.