Investigation of the most effective provocation test for patients with coronary spastic angina: usefulness of accelerated exercise following hyperventilation

This study sought to compare the clinical usefulness of the hyperventilation plus cold stress test or the hyperventilation combined with accelerated exercise test with other single tests in patients with coronary spastic angina. The study examined 24 patients (23 men, mean age 66 years) with angiographically confirmed coronary spastic angina and less than 50% stenosis. Moreover, none had spontaneous ST segment elevation before the study. Under no medication for at least 24 h prior, 4 procedures were performed from 09.00 h to 11.00 h: (i) a hyperventilation test for 5 min (HV(5)); (ii) HV(5) combined with a cold stress test for the last 2 min (HV(5)+CS(2)); (iii) a treadmill exercise test based on Bruce's protocol (TM(3)); and (iv) a treadmill exercise test accelerated at 1 min intervals according to Bruce's protocol immediately after HV(5) (HV(5)+TM(1)). The rate of appearance of chest pain and ischemia-induced ECG changes due to HV(5)+TM(1) were significantly higher than the other 3 tests. HV(5)+CS(2) was not superior to HV(5) alone. The incidence of provoked ST segment elevation due to HV(5)+TM(1) was higher than with the other 3 procedures. Thus, in patients with coronary spastic angina, no spontaneous ST segment elevation and near normal coronary arteries, HV(5)+CS(2) was no more useful than HV(5) alone. It is recommended that the newly designed HV(5)+TM(1) combination test be used for documenting evidence of ischemia in patients with coronary spastic angina, low disease activity and near normal coronary arteries.