The Effect on Blood Pressure in the Right Heart, Pulmonary Artery and Systemic Artery of Cardiac Standstill Produced by Carotid Sinus Stimulation

Abstract

In two patients with hypersensitive carotid sinus syndrome, cardiac standstill was induced while pressures were recorded in the pulmonary and femoral arteries and right heart. With onset of ventricular standstill, pressures in the right atrium and right ventricle equalized and gradually increased, that in the femoral artery decreased, and that in the pulmonary artery-fell until it became equal to right ventricular pressure, and then increased commensurately with it. All pressures then approached a uniform magnitude asymptotically: this uniform pressure is believed to correspond to the "static pressure." The manner in which the respective pressures returned to normal with resumption of normal cardiac rhythm is described, and certain unexpected findings are discussed.