Carotid-vertebral artery blood transit time in health and in neurological patients: a preliminary study by a non-invasive impedance method.

Thirty-one healthy subjects and nineteen neurological patients covering a range of chronic neurological and neurovascular syndromes were examined by an electrical impedance method. Two estimates of carotid-vertebral artery transit times were measured: one time taken between the Q wave of the EKG to the commencement of the next succeeding impedance pulse-volume wave (CT1), and the other, this estimate together with the time to maximum point of the impedance wave (CT2). Results indicated prolonged circulation times for the patients as compared with the controls without relevance to age in the case of CT1, although transit times did increase with age for CT2. It is suggested that this impedance technique may be valuable in the initial screening of transient cerebral ischaemia.