Monitoring of Postoperative Myocardial Ischemia and Infarction With Continuous ECG Measurements
Vanhatalo, Joonas (2017)
Vanhatalo, Joonas
2017
Master's Degree Programme in Biomedical Engineering
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
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Hyväksymispäivämäärä
2017-01-11
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201612154867
https://urn.fi/URN:NBN:fi:tty-201612154867
Tiivistelmä
Postoperative myocardial ischemia leading to myocardial infarction (PMI) after a non-cardiac surgery is shown to be common in selected population and is associated with increased mortality and morbidity in-hospital and long term. Primary and a relatively sensitive detection rate can be achieved using assays of a biomarker called cardiac troponin in order to indicate myocardial injury. However, for troponin concentration to rise an injury must have already occured. Electrocardiography(ECG) changes on the other hand are known to be present in the setting of myocardial ischemia immediately after diminished or restricted blood ow. In addition major part of the postoperative ischemic events are asymptomatic thus further stressing the importance of ECG monitoring. Despite the abundant clinical evidence supporting these facts the standard of practice in many hospitals does not include routine troponin assays or even routine ECG monitoring after non-cardiac surgery. Thus in order to increase the likelihood of timely detection of ischemic events continuous ECG monitoring in parallel with regular troponin assays should be performed to prevent the ischemia developing further in the rst place. At the same time this should be done e ciently with minimal burden for the patient. Recent advances are driving patient monitoring towards wireless approach which suits the needs placed by this scenario as well. In this thesis the ischemic events of patients undergoing a non-cardiac vascular surgery were studied in the Helsinki university central hospital. ECG was measured using a Holter ECG system in order to imitate the wireless monitoring setting. The monitoring time was 72 hours after a noncardiac vascular surgery. Additionally standard 12-lead snapshot ECG's were measured for comparison to determine the bene ts of continuous ECG monitoring. The performance of the continuous measurements was used to assess the quality of the measurements for future development of ischemia monitoring. A literature review of the relevant background of the topic and the current state of ischemia monitoring is given as well. Additionally a custom software analysis tool was developed in order to visualize and utilize the data in an orderly manner. The tool was used in visual annotations and post-processing of the data. From the study group of 56 patients, 19 were diagnosed to have ischemia. Out of the 19 patients, 5 were diagnosed to have myocardial infarction during the postoperative monitoring. All ischemia appeared as depression of the ST-segment. After analysing the data the ECG lead sensitivities were found to be consistent with similar studies and clinical guidelines. Moreover the ischemic burden revealed by continuous monitoring was considerable and increased cumulatively during the monitoring. The thesis shows evidence that continuous realtime ECG monitoring of certain postoperative patients would reduce the total ischemic burden of patients.