[Fluctuations in the stenocardia threshold of patients with ischemic heart disease]

In twenty-eight men (the mean age 49.3 +/- 3.2 years) with different clinical varieties of angina pectoris, analysis was made of the heart rate and the grade of ischemic depression of the ST segment, associated with anginous attacks seen during bicycle ergometry and other physical exercises in the course of daily cardiomonitoring. The data obtained indicate that in the same patient, the same grade of ischemic depression of ST was recorded despite varying heart rate. On the contrary, in spite of the same heart rate the grade of ischemic depression of the segment could vary. Dynamic coronary obstruction determined by the mechanisms of adrenergic vasoconstriction is the most probable cause of changeability of the threshold of angina pectoris in patients belonging to functional classes III-IV. The probability of fluctuations in the threshold of angina pectoris should be taken into consideration in deciding expert problems and in the assessment of the efficacy of antianginal therapy.