70-year old patient presenting with chest pain, dyspnoea and dizziness. BP 90/50. SaO2 83% RA

Describe and interpret this ECG


Main Abnormalities

  • Sinus tachycardia ~ 100 bpm
  • Anterior T wave abnormalities: inverted in V1-4
  • Inferior T wave abnormalities: inverted in III, aVF
  • Subtle ST elevation in III and aVF, without reciprocal changes

Significance of ECG Findings

This pattern of T wave inversions in the right precordial leads V1-4 plus the inferior leads (especially the rightward-facing lead III) is referred to as the right ventricular strain pattern. It is a marker of right ventricular hypertrophy or dilatation.


In a patient presenting with acute shortness of breath, the combination of…

  • Sinus tachycardia
  • RV strain pattern in V1-4 (+/- lead III)

… is highly suggestive of acute cor pulmonale due to massive pulmonary embolism.

However, these ECG changes are not specific to PE and may be seen in other conditions associated with pulmonary hypertension and RV enlargement including:


Anterior T-wave inversion in V1-3 is also seen in Wellens syndrome. The presence of concurrent inferior T-wave inversion, especially in leads facing the right ventricle (III), is highly specific for differentiating pulmonary embolism from Wellens syndrome. For another example of this pattern, see ECG Case 123.

Other ECG findings associated with pulmonary embolism include:

The often quoted SI QIII TIII  pattern (deep S wave in lead I, Q wave in III, inverted T wave in III) is neither sensitive nor specific for PE and is infrequently seen (20% of cases).

Similarly, sinus tachycardia is not as ubiquitous in PE as people seem to think (< 50% of cases), and certainly should not be relied up to exclude PE.

TOP 100 ECG Series

Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner


    • The presence of concurrent TWI in inferior leads, especially III facing the RV, is highly specific for differentiating PE from Wellens. See https://litfl.com/ecg-case-123/ for another great example of this. ECG changes in Wellens will also usually be dynamic.

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