Relation of Heart Rate and Systolic Blood Pressure to the Onset of Pain in Angina Pectoris

Arterial pressure was recorded directly and continuously in 15 patients with angina pectoris while pain was repeatedly induced by exercise of various types and severity. In every case, the precipitation of angina could be consistently related to the level reached by the product of heart rate and systolic blood pressure (corrected when necessary for changes in ejection time). This relationship persisted even when there were large variations in the type, intensity, and duration of the exercise and was also maintained in a patient in whom spontaneous and emotional episodes of pain were observed. A substantial improvement in exercise tolerance occurred in one patient and this was completely accounted for by a reduction in the circulatory response to exercise. It was concluded that the precipitation of angina is normally the result of a rise in the work of the myocardium to a critical level which is essentially fixed in each patient. The varying ease with which pain is provoked on different occasions can usually be explained by variations in circulatory response to the precipitating stress.