Pulmonary Embolism ECG Review

The most common ECG finding in the setting of a pulmonary embolism is sinus tachycardia. However, the “S1Q3T3” pattern of acute cor pulmonale is classic; this is termed the McGinn-White Sign.


A large S wave in lead I, a Q wave in lead III and an inverted T wave in lead III together indicate acute right heart strain. This pattern only occurs in about 10% of people with pulmonary embolisms and is similar to the ECG findings of a left posterior fascicular block, or LPFB. Recall that sinus tachycardia is actually the most common ECG finding during a pulmonary embolus.

ECG Examples:

1. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric, 6e
2. Surawicz B, et al. AHA/ACCF/HRS Recommendations for the Standardization and Interpretation of the Electrocardiogram. Circulation. 2009;doi:10.1161/CIRCULATIONAHA.108.191095.