Mental stress as an acute trigger of ischemic left ventricular dysfunction and blood pressure evaluation in coronary artery disease

Lay people and medical personnel alike share the belief that mental stress can precipitate acute myocardial ischemia, in which blood flow to the heart is temporarily interrupted, and coronary events such as heart attacks. The evidence so far has been largely anecdotal, and the mechanisms have not been identified. One of the difficulties is that most ischemic attacks are ''silent,'' that is, the patient is not aware of them. These attacks occur at relatively low heart rate elevations, follow a circadian, or 24-hour, rhythm, and vary greatly in frequency over time. New techniques have provided a closer look at these events. The authors used radionuclide ventriculography, examination of the heart using a radioactive substance, to detect abnormal wall motion of the left ventricle in 29 patients with exercise-induced ischemia. Patients underwent four mental tasks, followed by maximal bicycle exercise testing, while several measurements were made. The magnitude of abnormalities caused by the ''worst'' mental tasks was comparable to that caused by exercise. Electrocardiography (ECG) was a poor detector of ischemia compared with radionuclide ventriculography. The study also assessed some of the oxygen demand aspects of ischemia. Heart rates were lower under mental stress than under exercise stress; however, arterial blood pressure was significantly higher under mental stress conditions. Other researchers have reported similar findings. In patients with coronary artery disease, an ambulatory radionuclide detector (the VEST, by Capintec, Inc.) monitoring the left ventricular function can improve the ability to find and study transient myocardial ischemia. (Consumer Summary produced by Reliance Medical Information, Inc.)