Importance of understanding different factors that causes ST segment abnormalities

In a new publication from Cardiovascular Innovations and Applications; Sharen Lee, Gary Tse, Xin Wang, Adrian Baranchuk and Tong Liu from Laboratory of Cardiovascular Physiology, Hong Kong, China, Second Hospital of Tianjin Medical University, Tianjin, China and Queen's University, Kingston, Ontario, Canada consider ST-segment depression in leads I and aVL.

The 12-lead electrocardiogram (ECG) is a routinely performed test but is susceptible to misinterpretation even by experienced physicians. The authors report a case of a 72-year-old lady with no prior cardiac history presenting 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 were also observed in the precordial leads V2 to V6. By contrast, these abnormalities were notably absent in lead II. A repeat of the ECG taken 30 minutes later revealed the resolution of most abnormalities seen in the initial ECG on a background of high-frequency noise in the limb leads.

The patient 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.