VASODEPRESSOR AND CAROTID SINUS SYNCOPE

Abstract

Syncope, or fainting, is by definition a transient reaction, and only rarely does the physician have an opportunity to make careful observations during a spontaneous episode. Certain types of syncope which may be provoked at will, notably carotid sinus syncope,1spontaneous and induced orthostatic hypotension2and some rare examples of vagovagal syncope,3have been studied extensively. The introduction of the inkwriting electroencephalograph (Grass) offers a method of obtaining continuous simultaneous records of the electrical activity of the brain (electroencephalogram) and of the heart (electrocardiogram) during the syncopal experience and of correlating these with other clinical and physiologic data. In this paper we are reporting on the clinical, electroencephalographic, electrocardiographic and circulatory responses observed during a variety of syncopal reactions, including syncope provoked by venipuncture, by distention of the duodenum, colon, rectum or vagina, by hyperventilation and by carotid sinus reflex. The mechanisms of these various types of