The Prognosis of an Abnormal Electrocardiographic Stress Test

Abstract

Treadmill walking for 10 min at 3 mph against a 5% grade has been used as an electrocardiographic (ECG) stress test as part of a prospective epidemiologic study of 2,437 men. From 19532,437 men. From through 1966 have been done without untoward event.The criteria of an abnormal postexercise ECG were ischemic flattening or coving of the S-T segment, T-wave changes consistent with focal left ventricular epicardial ischemia, and paroxysmal left bundle-branch block.Of the 2,003 men exercised two or more times, 264 developed some manifestation of ischemic heart disease (IHD) and in 75 (30%) this was an abnormal ECG response to exercise. They had higher blood pressures and were more often heavy smokers than normal responders. Body weight and serum cholesterol were similar in the two groups. Over the next 5 years there was an 85% probability that these abnormal responders would develop angina pectoris or experience a myocardial infarction.These relatively insensitive but highly specific and reproducible ECG criteria accurately identify men with clinically silent but far-advanced coronary atherosclerosis, attested by the poor prognosis of an abnormal response. An abnormal postexercise ECG is valid evidence of IHD. A submaximal ECG stress test is useful in clinical and epidemiologic studies and might be useful in assessing the effectiveness of efforts to reduce the risk of IHD.Additional Indexing Words: Ischemic (coronary) heart disease Exercise IT IS generally, although not universally, accepted that transient abnormalities of intraventricular conduction and of ventricular repolarization appearing during or after exercise are manifestations of reversible myocardial ischemia. In the absence of myocardial or valvar dysfunction, anemia, electrolyte disturbance, or digitalis, these electrocardiographic abnormalities are imputed to the inability of coronary arteries narrowed by atheroma to deliver enough blood to meet the immediate energy requirements of the increased myocardial work load. The electrocardiographic criteria of induced myocardial

Cardiac evaluation of the patient with stroke.

“…- 23 In a prospective study, Froelicher and associates 24 screened 1,390 asymptomatic pilots for latent coronary artery disease by treadmill testing and followed them for an average of 6.3 years. Using angina, acute myocardial infarction, or sudden death as end points, exercise electrocardiography's sensitivity was 61% and its specificity was 92% for predicting future coronary events.…”

Prognostic Value of Exercise Tolerance Testing in Asymptomatic Chronic Nonischemic Mitral Regurgitation

“…Only a relatively small number of patients manifested newly developing ST segment depression after study entry, limiting our ability to assess the association between this descriptor and subsequent events, a relation previously reported among patients with coronary artery disease (22). However, events did not cluster among these patients; indeed, there was not even a non-significant tendency for such clustering.…”

“…Data were analyzed, post hoc, to determine whether ST segment depression first occurring after study entry added to the predictive value of this parameter, as it does for coronary artery disease (22); risk of endpoints was identical (hazard ratio=1.0, NS, Table 3) among patients with and without ST segment depression when the 5 patients who developed ST depression after study entry were added to those with ST depression at study entry and also was similar when these 5 patients were compared with those who did not manifest ST depression either at study entry or during follow-up (hazard ratio=0.9, NS, Table 3). ST depression with exercise had no predictive value for subsequent events even when analyses were adjusted for baseline variations in age, gender, etiology and chronic use of any cardiac medication or when the magnitude of the ST change was evaluated post hoc (NS, all comparisons) as a continuous variable, and no significant interaction was found between ST segment depression with exercise and exercise duration.…”

Clinical, Angiographic and Hemodynamic Characteristics of Patients with a Strongly Positive Exercise Test

“…Long-term follow-up studies of patients presenting for exercise evaluation have identified a relationship between the extent of S-T segment depression and subsequent coronary morbidity and mortality (12)(13)(14). These investigations did not document the anatomic extent o f coronary stenosis in the study popula tions.…”