Treadmill stress test using body surface mapping in coronary artery disease. The clinical significance of ST depression.

In this study we assessed in 27 patients with coronary artery disease whether the size of the ST-depression area, which was measured by body surface maps recorded before and after treadmill exercise, could be a useful indicator for evaluating coronary artery disease (CAD) quantitatively. The patients were divided into 3 groups on the basis of the findings of the left ventriculograms: patients with anterior asynergy (n = 6), those with inferior asynergy (n = 6) and those with no asynergy (n = 15). Coronary arteriograms were evaluated according to Pujadas, and epsilon Grade, as an index of the severity of CAD, was developed by adding the grade numbers of the 4 main coronary stems (right coronary artery, main trunk of the left coronary artery, left anterior descending artery and left circumflex artery). Patients with inferior asynergy and with no asynergy have ST-depression areas in proportion to their epsilon Grade (r = 0.845, p less than 0.001), whereas none of the patients with anterior asynergy showed ST-depression areas regardless of their epsilon Grade. Of 6 patients who had anterior asynergy, 5 (83%) had pathologic Q waves in the left anterior chest leads. These findings emphasize the clinical value of the ST-depression are for the quantitative and non-invasive diagnosis of CAD, especially in patients without pathologic Q waves in the left anterior chest leads.