Validity and predictive value of exercise induced inverted t-wave normalization for diagnosis of ischemic heart disease

ABSTRACT

To evaluate the usefulness and validity of the exercise-induced T wave normalization for prediction and diagnosis of ischemic heart disease and to assess and quantify its correlation to autonomic dysfunction. A cohort study Department of Medicine, Farwania Hospital, Kuwait One hundred and twenty-one patients with history of exertional chest pain with inverted T wave in the resting ECG but without history of myocardial infarction and 67 patients with T wave inversion during exercise test were included in the study. All patients underwent treadmill exercise ECG test and stress thallium scintigraphy in the course of their management. Exercise induced T-wave There was no significant difference between patients from both groups as regards the resting heart rate, the time of the exercise test, peak heart rate, heart rate recovery after exercise and QT dispersion after exercise, [p = NS]. Predictive indices revealed that exercise induced T wave normalization is sensitive but not a specific indicator for prediction of ischemic heart disease, as the sensitivity was 71%, specificity = 49.2%, accuracy = 63.2%, positive predictive value = 74.4% and negative predictive value = 44.8%. A significant relation between age, smoking status, diabetes mellitus status and exercise induced T wave normalization [p < 0.05] was observed. Exercise induced T wave normalization is a sensitive but not specific marker of exercise induced myocardial ischemia and this may be due to autonomic dysfunction with impaired parasympathetic function and unopposed sympathetic action