The Brain–Heart Connection

N eurocardiology has many dimensions, but it may be conceptualized as divided into 3 major categories: the heart's effects on the brain (eg, cardiac source embolic stroke), the brain's effects on the heart (eg, neurogenic heart disease), and neurocardiac syndromes (eg, Friedreich disease).The present review deals with the nervous system's capacity to injure the heart.This subject is inherently important but also represents an example of a much more widespread and conceptually fascinating area of neurovisceral damage in general. History of Learning the Nature of the Brain-Heart ConnectionIn 1942, at the culmination of his distinguished career as Professor of Physiology at Harvard Medical School, Walter B. Cannon published a remarkable paper entitled "'Voodoo' Death," 1 in which he recounted anecdotal experiences, largely from the anthropology literature, of death from fright.These often remote events, drawn from widely disparate parts of the world, had several features in common.They were all induced by an absolute belief that an external force, such as a wizard or medicine man, could, at will, cause demise and that the victim himself had no power to alter this course.This perceived lack of control over a powerful external force is the sine qua non for all the cases recounted by Cannon, who postulated that death was caused "by a lasting and intense action of the sympathico-adrenal system."Cannon believed that this phenomenon was limited to societies in which the people were "so superstitious, so ignorant, that they feel themselves bewildered strangers in a hostile world.Instead of knowledge, they have fertile and unrestricted imaginations which fill their environment with all manner of evil spirits capable of affecting their lives disastrously."Over the years since Cannon's observations, evidence has accumulated to support his concept that "voodoo" death is, in fact, a real phenomenon but, far from being limited to ancient peoples, may be a basic biological principle that provides an important clue to understanding the phenomenon of sudden death in modern society as well as providing a window into the world of neurovisceral disease (also known as psychosomatic illness).George Engel collected 160 accounts from the lay press of sudden death that were attributed to disruptive life events. 2He found that such events could be divided into 8 categories: