Hypertension secondary to bradycardia: blood pressure regulation under the effect of impaired cerebral blood flow and bradycardia.

Ninety-two patients of advanced age were studied in whom arterial hypertension was associated with chronic bradycardia, the cessation of bradycardia after pacemaker implantation was followed by a significant fall or permanent normalization of the high blood pressure. In three cases cerebral blood flow was found low, but it increased when the heart rate was normalized on pacing. In order to check the results obtained in humans, cerebral blood supply was restricted by carotids ligation, in some animals the vertebral artery of one side was also ligated. During obstruction of cerebral blood flow, bradycardia induced by av block or vagal stimulation was followed by an increase in arterial blood pressure. It is suggested that disturbances of cerebral blood flow associated with bradycardia have a decisive part in the pathogenesis of hypertension in old age.