ST-Segment Depression in Leads I and aVL: Artifactual or Pathophysiological Findings?

Abstract

The 12-lead electrocardiogram (ECG) is a routinely performed test but is susceptible to misinterpretation even by experienced physicians. We report a case of a 72-year-old lady with no prior cardiac history presented to our hospital with atypical chest pain. Her initial electrocardiogram shows an initial ST depression followed by positive deflections leads I and aVL. Non-physiological ST segment and T-wave changes are also observed in the precordial leads V2 to V6. By contrast, these abnormalities are notably absent in lead II. A repeat of the ECG taken 30 minutes later reveals the resolution of most abnormalities seen in the initial ECG on a background of high-frequency noise in the limb leads. She was referred to the cardiology department for further management. An urgent echocardiogram revealed no regional wall motion abnormalities with preserved ejection fraction, and her coronary angiogram revealed no significant coronary stenosis. This case illustrates the importance of understanding different factors that can cause ST segment abnormalities, notably artifactual changes that can mimic ST segment myocardial infarction.