Measurement of the Angina Threshold Using Atrial Pacing: A New Technique for the Study of Angina Pectoris

Abstract
A threshold level of tension-time index has been found in patients with angina pectoris above which angina occurred. End-diastolic x-ray films showing an increase, rather than the usual decrease, in heart size with increasing rate were thought to explain the absence of a threshold level in some patients.