Exercise Stress Testing in Angina Patients with Positive Response to Hyperventilation Testing: Influence of the Coronary Artery Tone

Abstract

We studied the exercise stress test and the coronary artery tone in two groups of angina patients with comparable coronary atherosclerosis. Group I (20 males and 5 females, mean age 53.5 years) with a positive, and group 11 (22 males and 3 females, mean age 52.5 years) with a negative response to the hyperventilation test (HVT). A positive exercise stress test (ST depression ≥1 mm) was found in 24 patients in group 1 vs. 15 in group II (p<0.01), despite a lower maximal rate pressure product (198±11.2 vs. 236±10.1, p<0.05) and maximal work load (110 W±7.1 vs. 136±7.4 W, p<0.02) in group I. A high coronary artery tone (dilatation (DIL %) of the coronary arteries after nitroglycerin ≥ 10%) was found in 18 patients in group I and in 4 in group II (p<0.01). DIL % was 22.6±3.8 vs. 5.8±1.4 in groups I and II, respectively (p<0.005). DIL% was significantly related to persistence of ST depression after exercise (r=0.36, p<0.05), and 21 of 22 patients with high tone had a positive exercise stress test vs. 18 of 28 with low tone (p<0.05). These findings suggest that the coronary artery tone influences the response to exercise in some patients with angina. Since the patients in group I were identified by HVT, our results underline the clinical relevance of this test.