Hyperventilation and ergonovine tests in Prinzmetal's variant angina: comparative sensitivity and relation with the activity of the disease.

Hyperventilation (HV) and ergonovine (E) tests were carried out in a group of 32 patients with variant angina to compare their sensitivity and to correlate the results with the activity of the disease. The HV test was positive in 84% of the patients and E in 94% of them; the percentage of positive responses to HV was similar to that to E (96% vs 100%) in the patients with daily attacks, while it was lower (55% vs 77%) in those with sporadic attacks. All 27 patients with a positive HV also had a positive response to E, while of the five patients with a negative HV, two also had a negative response to E and the other three had a positive E at a higher dose than that of the patients with daily attacks. The incidence of chest pain and of ST-segment elevation or depression or T-wave positivization was similar during the two tests; however, spontaneous remission of ischaemia was more frequent after HV than after E and ventricular arrhythmias less frequent during the HV test. At the onset of myocardial ischaemia pH was significantly higher compared with basal values (7.51 +/- 0.07 vs 7.38 +/- 0.05, P less than 0.001), while double product was not significantly different compared with basal (10.0 +/- 2.4 vs 9.2 +/- 2.1).(ABSTRACT TRUNCATED AT 250 WORDS)