Carotid sinus nerve stimulation in the treatment of angina pectoris and supraventricular tachycardia.

E. BRAUNWALD: * The carotid sinus is a dilatation of the internal carotid artery near its origin at the bifurcation of the common carotid artery. This area of the vessel is richly supplied by nerve receptors which lead into the carotid sinus nerve; the latter in turn joins the ninth cranial nerve, the glossopharyngeal, which leads to vasomotor cen-ters in the medulla. Since the classic work of Hering in 1923 it has been known that the carotid sinuses play a critical role in the regulation of arterial pressure. Stimulation of the pressure receptors (baroreceptors) in the carotid sinuses and aortic arch results in reflex arteriolar dilation and reduction of heart rate and myocardial contractil-Supported ity, this as a consequence of a reduction in the frequency of sympathetic efferent impulses and an increase in the frequency of vagal impulses.1 The opposite changes occur when the pressure acting upon these receptors is reduced. For this reason, the sensory nerves from the baroreceptors are called buffer nerves; in normal circumstances they are continuously active in the regulation of arterial pressure, heart rate and myocardial contractility. It is that circulatory