John MacWilliam, evolutionary biology and sudden cardiac death.

Sudden death is frequently of cardiac origin, and its most common electrophysiologic mechanism is ventricular fibrillation. The concept that sudden death in human beings is due to ventricular fibrillation was first proposed by MacWilliam exactly 100 years ago, well before the electrocardiogram was invented. To conduct his experimental work, MacWilliam devised methods that laid the foundations for modern cardiac research and that provided the first comprehensive approach to successful cardiopulmonary resuscitation. He recognized the role of the autonomic nervous system in modulating both the mechanical and the electrical properties of the heart, and was the first to suggest that this effect had a role in the genesis of sudden death. On the centennial of his theory of sudden death, MacWilliam's concepts are reviewed in the context of the effect of Darwinian influence on British physiology. It is suggested that his theorem was based on both sound experimental data and comparative physiology, drawing on the new evolutionary principle of similar structure and function in the hearts of various species. MacWilliam's basic physiologic concepts have survived intact for a century, greatly influencing more than three generations of research and practice in clinical cardiology.