Cerebral microembolism detected by transcranial Doppler during cardiac procedures

Background and Purpose-Cerebral embolism with clinical sequelae may rarely complicate cardioversion and cardiac catheterization. Transcranial Doppler sonography has recently been introduced to monitor microemboli entering the middle cerebral artery in cardiac and carotid surgery. We therefore used this technique to evaluate the risk of asymptomatic embolism during common cardiac procedures. Methods-Patients were monitored by transcranial Doppler while undergoing direct current cardioversion (n = 15) and cardiac catheterization (n = 17). Results-Microemboli were detected in all patients having cardiac catheterization but in only 1 patient after cardioversion. Conclusions-Microembolism occurred frequently during cardiac catheterization and rarely during cardioversion. It is not yet known whether this has clinical relevance.