Continuous vectorcardiography in cardiac surgery: natural course of vector changes and relationship to myocardial oxygen uptake |
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Authors: | O Wesslén R Ekroth P O Joachimsson L Nordgren S O Nystr?m H Tydén |
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Institution: | Department of Thoracic and Cardiovascular Surgery, University Hospital, Uppsala, Sweden. |
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Abstract: | Continuous vectorcardiography was registered before and during the first 18 hours after cardiac surgery in 53 patients. QRS vector changes (QRS-VD) occurred during the operation, but no further changes were observed postoperatively. The ST vector (ST-VM) increased during the operation, and a further slight increase occurred postoperatively. Perioperative myocardial infarction occurred in three patients. Their ST-VM was higher than the average in patients without myocardial infarction, while QRS-VD did not differ from the average pattern. Twelve other patients were studied in pacemaker-induced moderate tachycardia. QRS-VD increased in proportion to heart-rate changes (rs median = 0.93, p less than 0.01). QRS-VD also correlated with myocardial oxygen uptake (rs median = 0.62, p less than 0.05). The ST-VM responses were not uniform. The data suggest that vectorcardiogram variables can provide information related to myocardial energy metabolism. |
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