Origin of cerebrospinal fluid pulsations

Abstract

Experiments were performed in dogs to determine whether cerebrospinal fluid pulses were venous or arterial in origin. Since all cerebrospinal fluid pulsations synchronous with the heart beat must originate either in the right atrium or the left ventricle, interventions were designed to dissociate right atrial and left ventricular events. In the majority of normal dogs, the major pulsation in the cerebrospinal fluid was arterial in origin, but smaller venous pulsations were usually also present. Under conditions in which arterial pressure is decreased and/or venous pressure is increased, the venous pulsation may predominate. Interventions in which right atrial waves could be clearly demonstrated included the surgical production of complete heart block, partial pulmonary artery occlusion, and hypothermia. Cerebrospinal fluid pulsations of arterial origin were demonstrated during pulsus alternans, complete right heart bypass, mechanical stimulation of the left ventricle, and in some dogs with complete heart block. Recognition of the origin of cerebrospinal fluid pulsations is of importance in understanding normal pressure/flow relationships.