Inverted T waves on electrocardiogram: myocardial ischemia versus pulmonary embolism

Electrocardiogram (ECG) is of limited diagnostic value in patients suspected with pulmonary embolism (PE). However, recent studies suggest that inverted T waves in the precordial leads are the most frequent ECG sign of massive PE (Chest 1997;11:537). Besides, this ECG sign was also associated with the best sensitivity, specificity, and positive and negative predictive values for diagnosing PE. We report 2 cases with similar ECG findings that were referred to us as unstable angina. Both were hemodynamically stable and had moderate-size pulmonary emboli. The ECG findings reverted to normal within a week of anticoagulation treatment. Our observation suggests that even a moderate-size PE can cause these ECG changes.