Dynamic QRS-complex and ST-segment monitoring by continuous vectorcardiography during carotid endarterectomy

• Published in: British journal of anaesthesia : BJA Vol. 90; no. 2; pp. 142 - 147
• Main Authors: Kawahito, S., Kitahata, H., Tanaka, K., Nozaki, J., Oshita, S.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2003; Oxford University Press; Oxford Publishing Limited (England)
• Subjects: Aged; Anesthesia; Anesthesia depending on type of surgery; Anesthesia, General; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Biological and medical sciences; carotid endarterectomy; Electrocardiography. Vectocardiography; Electrodiagnosis. Electric activity recording; Endarterectomy, Carotid - adverse effects; Female; heart; heart, ischaemia; Humans; Intraoperative Complications - diagnosis; Intraoperative Complications - etiology; Intraoperative Complications - physiopathology; Investigative techniques, diagnostic techniques (general aspects); ischaemia; Male; Medical sciences; Middle Aged; monitoring; Monitoring, Intraoperative - methods; monitoring, vectorcardiography; Myocardial Ischemia - diagnosis; Myocardial Ischemia - etiology; Myocardial Ischemia - physiopathology; surgery; surgery, carotid endarterectomy; Thoracic and cardiovascular surgery. Cardiopulmonary bypass; vectorcardiography; Vectorcardiography - methods; monitoring, vectorcardiography; heart, ischaemia; surgery, carotid endarterectomy; heart, ischaemia; monitoring, vectorcardiography; surgery, carotid endarterectomy; QRS interval; Stenosis; Cardiovascular disease; Vectorcardiography; Myocardial disease; Arterial disease; Vascular disease; Ischemia; Surgery; Complication; Diagnosis; Endarteriectomy; Cerebrovascular disease; Monitoring; Human; Nervous system diseases; ST interval; General anesthesia; Intraoperative; Coronary heart disease; Cerebral disorder; Carotid; Central nervous system disease; Myocardium
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/aeg031

Many authors report a high incidence of cardiac events during carotid endarterectomy. The aim of the present study was to evaluate the usefulness of dynamic continuous on-line vectorcardiography for monitoring the occurrence of myocardial ischaemia during carotid endarterectomy. We studied 21 patients undergoing carotid endarterectomy. Patients underwent general anaesthesia with isoflurane or sevoflurane. The vectorcardiogram was monitored continuously during carotid endarterectomy. Electrodes were placed according to the previously described lead system and connected to a computerized system for on-line vectorcardiography. Two trend variables were recorded: the QRS vector difference, which reflects changes in the shape of the QRS complex; and the ST vector magnitude, which represents deflection of the ST segment from the isoelectric level. The ST segment deflection was measured 60 ms after termination of the QRS complex. Vectorcardiography was successfully recorded in all 21 patients. Three patients showed intraoperative vectorcardiogram abnormalities. In one of these three patients, both ST vector magnitude and QRS vector difference increased after induction of anaesthesia and ST vector magnitude returned to baseline after administration of nitroglycerin. In the other two patients, both ST vector magnitude and QRS vector difference gradually increased after cross-clamping of the internal carotid artery and ST vector magnitude returned to baseline after unclamping. QRS vector difference remained elevated for several hours in all three patients. Monitoring ST vector magnitude and QRS vector difference by vectorcardiography may be useful for identifying myocardial ischaemia during carotid endarterectomy.