Reproducibility of work performance at serial exercises in patients with angina pectoris

The reproducibility of serial upright exercises in patients with ischaemic heart disease was tested. Five short term exercises (4--8 min) with continuous load increase and with 30 min rest intervals between tests were used. No tendency to change was found concerning work time to appearance of angina (APT), maximal working time (MWT) or time for disappearance of angina after exercise (DPT). The coefficient of variation was low for APT and MWT but considerably higher for DPT, being 9, 5 and 27%, respectively. MWT was considered as the end-point of choice. The ST depression at MWT showed no tendency to change and the variation was moderate (14%), while at APT and DPT the variation was high (52%), but, likewise, with no tendency to change. The maximal heart rate increased slightly and significantly (P less than 0.001), while the maximal blood pressure was constant throughout tests, thus the maximal rate pressure product tended to increase. This indicates a slight improvement of the myocardial performance at serial exercises, which, however, does not affect the reproducibility of the anginal reaction.