Improvement of cerebral blood flow and cognitive function following pacemaker implantation in patients with bradycardia.

We investigated the effects of pacemaker implantation on cerebral blood flow and cognitive function in 14 severely bradycardic patients (mean age 75.2 years). Cerebral blood flow and verbal intelligence improved after the pacemaker implantation. Systolic and mean arterial blood pressure was significantly reduced after the implantation. Changes in cerebral blood flow significantly correlated with changes in heart rate in polynomial regression analysis, but not with changes in cardiac output. Before the implantation, verbal cognitive function was lower in bradycardic patients than in age-matched control subjects, and brain CT showed significant advanced atrophy in these patients. However, verbal cognitive function was also improved after the implantation. Pacemaker implantation in the severe bradycardic elderly should be beneficial not only for cardiac function but also for brain function. We concluded that these results suggest that heart rate is one of the important factors in the regulation of cerebral circulation in patients with severe bradycardia. Pacemaker implantation in the elderly improved quality of life and may prevent mental deterioration.