Mental stress test is an effective inducer of vasospastic angina pectoris: comparison with cold pressor, hyperventilation and master two-step exercise test

Abstract

Background: Cold pressor, hyperventilation and exercise stress tests were usually used for inducing an angina attack in patients with vasospastic angina pectoris. We induced vasospastic angina attack using the mental calculation stress test, and compared the results with those using other stress tests. Subjects and methods: Subjects were 29 patients with vasospastic angina pectoris. Their ages were 60.8±8.4 years. Coronary vasospasm was induced by an acetylcholine infusion test during coronary angiography. The mental stress test was performed as follows; after memorizing six digits numbers, they repeated these numbers in reverse for 5 min, and performed serial subtraction of 17 from 1000 for 5 min. Blood pressure, heart rate and ECG were recorded every 1–5 min during the mental stress test. The serum concentrations of epinephrine and norepinephrine were measured before and during the mental stress test. We compared these results with those obtained using cold pressor, hyperventilation and the Master two-step exercise stress test. Results: (1) Eight of the 29 patients (28%) showed ischemic ST–T change, which was caused by the mental stress test. (2) The increase in norepinephrine was greater in patients with an ST–T change than without an ST–T change (0.11±0.06 vs. 0.04±0.04 ng/ml, P<0.01). (3) The incidence of the ST–T change caused by the mental stress test (28%) was similar to the cold pressor test (27%) and greater than that caused by the hyperventilation test (13%). The incidence of ST–T change caused by the Master two-step test was 55%. Conclusions: The mental stress test is an effective inducer of vasospastic angina attack, and attack may be induced by neurohumoral vasoconstrictive reflex and/or increased left ventricular afterload.