ECG Case 070

Elderly patient presenting with sudden onset of chest pain and shortness of breath. Hypoxic (SaO2 82% RA) and hypotensive (80/50). Describe and interpret his ECG


Describe and interpret this ECG


There are multiple features suggestive of right ventricular hypertrophy or RV strain:

Given the clinical history, the most likely scenario is acute right heart strain due to massive pulmonary embolism.

A similar ECG pattern may also be seen with chronic cor pulmonale, pulmonary hypertension or RV hypertrophy (e.g. due to congenital heart disease).


ECG changes in pulmonary embolism include:

  • Sinus tachycardia – the most common abnormality; seen in 44% of patients.
  • Complete or incomplete RBBB associated with increased mortality; seen in 18% of patients.
  • Right ventricular strain pattern –  T wave inversions in the right precordial leads (V1-4) ± the inferior leads (II, III, aVF). This pattern is seen in up to 34% of patients and is associated with high pulmonary artery pressures.
  • Right axis deviation – seen in 16% of patients. Extreme right axis deviation may occur, with axis between zero and -90 degrees, giving the appearance of left axis deviation (“pseudo left axis”).
  • Dominant R wave in V1 – a manifestation of acute right ventricular dilatation.
  • Right atrial enlargement (P pulmonale) – peaked P wave in lead II > 2.5 mm in height. Seen in 9% of patients.
  • SI QIII TIII  pattern – deep S wave in lead I, Q wave in III, inverted T wave in III. This “classic” finding is neither sensitive nor specific for pulmonary embolism; found in only 20% of patients with PE.
  • Clockwise rotation – shift of the R/S transition point towards V6 with a persistent S wave in V6 (“pulmonary disease pattern”), implying rotation of the heart due to right ventricular dilatation.
  • Atrial tachyarrhythmias – AF, flutter, atrial tachycardia. Seen in 8% of patients.
  • Non-specific ST segment and T wave changes, including ST elevation and depression. Reported in up to 50% of patients with PE.

Simultaneous T wave inversions in the inferior (II, III, aVF) and right precordial leads (V1-4) is the most specific finding in favour of 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 |

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.