The vertige larynge of Charcot,1 the tussis convulsiva of Heberden,2 and other variants of syncopal states have been described throughout the history of medicine. It has even been suggested that death by crucifixion may be a form of fatal syncope.3 Early clinical observations during the practice of bloodletting suggested that a decrease in both heart rate and blood pressure occurred during syncopal attacks. The relative contribution of the nervous system to bradycardia and hypotension still remains controversial despite the almost 2 centuries of investigations into nervous influences on the heart. Central to this debate is the concept of an inhibitory reflex arc among the heart, brain, and circulatory system. The goals of this article are 3-fold: to trace the contributions of bloodletting to our understanding of syncope, to articulate the experimental and conceptual history of this reflex arc with special attention to cardiac innervation, and to show that an overemphasis on vagally mediated bradycardia led to a delay in recognizing the importance of sympathetic effector systems in the production of hypotension.
Nahm F, Freeman R. Syncope and the History of Nervous Influences on the Heart. Arch Neurol. 2003;60(2):282-287. doi:10.1001/archneur.60.2.282