Minimal influence of anaesthesia and abdominal surgery on computerized vectorcardiography recordings

Myocardial infarction still represents a major cause of morbidity and mortality following surgical procedures. Continuous computerized on-line vector-ECG has previously been shown to be useful in the detection of myocardial ischaemia, in acute myocardial infarction and unstable angina pectoris and for ischaemia monitoring after PTCA procedures. This method was presently tested for the possible influence of anaesthesia and surgery during cholecystectomy under general anaesthesia (n = 9), and during inguinal hernia repairs using a spinal block (n = 5). The patients had no history, symptoms or signs of ischaemic heart disease. Analyses of vectorcardiographic changes were made in relation to predefined standardized anaesthetic and surgical procedures, all of which potentially could influence the vector-ECG. Three vectorcardiographic trendparameters were studied: QRS-vector difference, ST-vector magnitude and ST-change vector magnitude. The overall vectorcardiographic changes were minimal and smaller than vectorcardiographic changes previously reported during myocardial ischaemia and infarction. Since anaesthetic and surgical procedures per se had only minor effects on the vector ECG recordings, it is concluded that continuous computerized on-line vectorcardiography will not be skewed by these procedures. Hence, vectorcardiography has the potential of becoming a new monitor for the detection of perioperative myocardial ischaemia.