Exercise stress testing in angina patients with positive response to hyperventilation testing: influence of the coronary artery tone.

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 II (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 greater than or equal to 1 mm) was found in 24 patients in group I vs. 15 in group II (p less than 0.01), despite a lower maximal rate pressure product (198 +/- 11.2 vs. 236 +/- 10.1, p less than 0.05) and maximal work load (110 W +/- 7.1 vs. 136 +/- 7.4 W, p less than 0.02) in group I. A high coronary artery tone (dilatation (DIL%) of the coronary arteries after nitroglycerin greater than or equal to 10%) was found in 18 patients in group I and in 4 in group II (p less than 0.01). DIL% was 22.6 +/- 3.8 vs. 5.8 +/- 1.4 in groups I and II, respectively (p less than 0.005). DIL% was significantly related to persistence of ST depression after exercise (r = 0.36, p less than 0.05), and 21 of 22 patients with high tone had a positive exercise stress test vs. 18 of 28 with low tone (p less than 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.