BIOLOGICALRESEARCHFORNURSINGVol. 3,No. 2,October 2001Wung / Computer-Assisted ST-Segment Analysis Computer-Assisted Continuous ST-Segment Analysis for Clinical Research: Methodological Issues

Continuous ST-segment monitoring has been used to detect acute myocardial ischemia, determine the success of the reperfusion therapy, and predict out-comes in both research and a variety of clinical set-tings. However, analyzing the abundant electrocardi-ography (ECG) data recorded using continuousmultilead ST-segment monitoring techniques is time consuming and requires expertise. Experienced data interpreters in dedicated ECG core laboratories handle many con-tinuous ECG data records from large clinical trials. Little information on measurement issues for com-puter-assisted ST-segment analysis is available for individual investigators. Unsupervised or inexperi-enced computer analysis of ST-segment deviations can, under certain circumstances, yield invalid or unreliable summary indices. The goal of this article is to discuss basic ST-segment measurement principles in evaluating acute myocardial ischemia and method-ological issues surrounding the use of computer-assisted ST-segment analysis for continuous ECG data. Variables affecting ST-segment measurements will be examined. Sources and examples of variability for these potential errors will be identified. Key words: Computer assisted, ST-segment, myocardial ischemia, electrocardiography, postural, contrast media Continuous ST-segment monitoring is important in numerous patient populations that are at risk for myo-cardial ischemia. Therefore, it is useful in research and a variety of clinical settings. For example, continuous ST-segmentmonitoring provides valuable information related to the occurrence of reperfusion and reocclu-sion in patients with acute coronary syndromes (Krucoff and others 1993;Klootwijk and others 1996). Interpre-tation of the ST-segment trend data aswell as detection and quantification of myocardial ischemia can yield important prognostic information (Barbash and other