SYNCOPE AND CONVULSIONS DUE TO A HYPERACTIVE CAROTID SINUS REFLEX

Abstract

For many years it has been known that pressure over the vagus nerve produces slowing of the heart.¹Not until 1923, however, was the true mechanism of this phenomenon recognized. Hering²conclusively demonstrated in animals that slowing of the heart and other effects of such pressure are due to reflexes arising in the carotid sinus. His work has been amply confirmed, particularly by Heymans.³The application of these findings to man has been rather recent. A report of fifteen cases by Weiss and Baker⁴demonstrated that an abnormally sensitive carotid sinus mechanism can be responsible for attacks of unconsciousness and convulsions and that such attacks can be reproduced by pressure over one carotid sinus. In most of the fifteen patients the attacks were associated with cerebral anoxemia resulting either from cardiac asystole or from a primary reflex depression of the blood pressure. In two patients, however,