Quantitative Studies in Man of the Cardiovascular Effects of Reflex Vagal Stimulation Produced by Carotid Sinus Pressure: I. Localization of an Increased Effect in a Patient with Angina Pectoris

Abstract

In a 2-yr. period the effect of carotid sinus pressure on auriculo-ventricular conduction in a 70-yr.-old man with angina pectoris increased markedly. At first, right carotid sinus pressure had no effect, whereas left carotid sinus pressure gave only P-R interval prolongation. Two yrs. later, pressure on either side produced dropped beats. The maximum effect on the sino-auricular rate remained the same. No other change could be detected in the patient''s heart during this period. The site of the cause of the increased vagal effect was either in the intrinsic cardiac nerves to the atrio-ventricular node or in the node itself.