Some patients with angina due to narrowing of the coronary arteries can develop chest pain both at rest, during periods of psychologic stress, and during exercise. Monitoring the frequency of angina with continuous electrocardiography using a Holter monitor demonstrates that the majority of episodes are silent and not perceived by the individual and many occur at relatively low heart rates. To investigate the role of spasm or narrowing of blood vessels in precipitating angina, we studied patients with narrowing of the coronary arteries during rest and exercise and after mental stress induced by playing a video game and measured blood flow using positron emission tomography. A subset of patients developed narrowing of blood vessels with exercise which resulted in reduced blood supply to the heart muscle and precipitated ischemia (angina) at low heart rates. We are currently investigating the effects of mental stress in producing spasm, and the effect of drug therapy.
