Tracker--an ambulatory recorder for ST-segment monitoring?
If ST-segment shifts are markers for ischaemic heart disease, they must be recorded accurately so that reliable diagnoses may be made. It is important to establish whether ST segments are distorted when recorded with ambulatory recorders. The Tracker/Replay II system (Reynolds Medical Ltd) is a machine widely used in Europe, yet little has been published assessing its performance when recording ST segments. We have therefore investigated the Tracker/Replay II system using electrocardiograms from patients with ischaemic heart disease and synthesized test signals to see if it could accurately reproduce ST-segment levels. We found that when recording QRS complexes at the upper limit of normal (2 mV and 110 ms), significant (0.14 mV) artefactual ST-segment changes were produced. The distortion was less for narrower or smaller complexes.
Tayler
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Cardiac Department, Northern General Hospital, Sheffield, U.K.
Oakley
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D000553:Ambulatory Care; D000572:American Heart Association; D003327:Coronary Disease / Q000175:diagnosis* / Q000503:physiopathology; D004562:Electrocardiography / Q000592:standards*; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000592:standards; D015203:Reproducibility of Results; D013637:Tape Recording / Q000295:instrumentation* / Q000592:standards; D014481:United States