Influence of atenolol on the relationship between heart rate and QT interval in patients with exercise-induced myocardial ischemia.

Summary: The aim of this study was to analyze the relationship between heart rate and QT interval (HR-QT) during exercise in control subjects (Group A) and in patients with coronary artery disease (CAD) with effort angina and without previous myocardial infarction (MI) (Group B). The diagnosis of CAD was confirmed by coronarographic examination. The correlation HR-QT was significant (p 1 mm) frequently occurred, a longer QT interval was present in Group B. Moreover, in Group B, the QT interval in the presence of ECG signs of ischemia was significantly longer (peO.01) than in Group A at comparable heart rates both on effort and at rest, thereby confirming the result obtained by comparing both regression lines. The same effort protocol was repeated in Group B patients after acute administration of atenolol 100 mg per 0s. After