Mechanisms of Fibrillation: Neurogenic or Myogenic? Reentrant or Focal? Multiple or Single?: Still Puzzling After 160 Years of Inquiry

The mechanisms of initiation and maintenance of ventricular fibrillation (VF) we have been hotly debated since Hoffa and Ludwig first observed and documented the bizarre chaotic action of ventricles after exposure to electrical current.1 During this initial period of inquiry the majority of prominent physiologists favored a neurogenic origin of arrhythmogenesis with abnormal impulse formation within a specialized network of nerve cells, which were considered the primary culprit of arrhythmogenesis. Vulpian, in his work Note sur les effets de la faradisation directe des ventricules du coeur le chien in 1874, however, was the first to suggest a myogenic origin of arrhythmogenesis, postulating that the cardiac muscle fibers themselves and not a specialized nerve network were responsible for initiating and sustaining abnormal cardiac rhythms.2 In line with this observation he coined the term “mouvement fibrillaire ” or fibrillation to emphasize the myogenic nature of the process that he had observed. A former student of Ludwig, John McWilliam of Scotland presented similar observations supporting the myogenic nature of fibrillation and was the first to suggest in his work titled Fibrillar contraction of the heart in 1887 that disturbances in impulse propagation were responsible for the onset of fibrillation.3 In addition to the