title: Painless ST-segment depression in patients with angina pectoris. Correlation with daily activities and cigarette smoking.
abstract: Ambulatory electrocardiographic monitoring was employed in 33 patients with angina pectoris and abnormal stress tests to determine the frequency with which myocardial ischemia manifested by painless ST-segment depression occurred during normal activity. ST-segment depression occurred in 24 patients during the monitoring period; and in 21, it occurred either solely in the absence of pain or both with and without pain. Of 109 recorded episodes of ST-segment depression, 61 percent were painless. The frequency of painless ST-segment depression was independent of activity other than automobile driving, during which all episodes were painless. In patients who smoked cigarettes, ST-segment depression was more common while smoking, but the incidence of painless ST-segment depression was not altered. The study indicates that ST-segment depression occurs more commonly in the absence than in the presence of chest pain and that ambulatory electrocardiographic monitoring is a useful method of determining the frequency of myocardial ischemia during normal daily activity.
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis*; D001334:Automobile Driving; D004435:Eating; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain; D005082:Physical Exertion; D012146:Rest; D012907:Smoking