The Carotid Sinus Reflex in Patients with Hypertension.

The observation that a state of elevated blood pressure develops in animals after denervation of the carotid sinus and aortic arch (1) has suggested that certain forms of hypertension in man might similarly be due to a failure of the depressor mechanism. Several studies have lent some support to this hypothesis (2, 3, 4). The evidence may be summarized briefly as follows: direct stimulation of the carotid sinus endings in hypertensive patients by digital pressure over the walls of the sinus causes a marked fall in blood pressure; however, alteration of pressure within the carotid sinus by digital compression and release of the common carotid artery below the sinus produces only minimal or negligible changes in blood pressure or heart rate. The conclusion has therefore been drawn that in hypertension there exists a certain degree of insensitiveness of the carotid sinus endings to their physiologic stimulus, namely changes in intravascular pressure within the sinus. The suggestion, furthermore, has been made that in these patients this defect is, in part at least, responsible for the development of the elevation of blood pressure (4, 5). The desirability of reexamining the observations which are the basis of these claims concerning the etiology of hypertension in man is apparent.