Acute pulmonary embolism (PE) is a common condition that can be both severe and difficult to diagnose. Half of all acute PE cases are diagnosed in the emergency department, and acute PE follows acute coronary syndrome as the second most common cause of sudden unexpected death in outpatients. Also, right ventricular dysfunction is a consequence of massive/submassive acute pulmonary embolism and correlates with a poor prognosis and high mortality rate. Although an ECG lacks both sensitivity and specificity for acute PE, there are some clues that can help in determining the size of an acute PE.
What are some of the common ECG changes seen with massive acute PE? 1
| ECG Changes | Massive PE (%) | Non-Massive PE (%) |
| Anterior Ischemic Pattern | 85 | 19 |
| S1Q3T3 | 54 | 54 |
| Sinus Tachycardia | 36 | 0 |
| Low Voltage | 36 | 36 |
| RBBB | 22 | 24 |
| Pulmonary P Waves | 7 | 0 |
Study methodology: 80 patients enrolled, prospective study
Conclusions:
Anterior ischemic pattern (inverted T waves) on ECG was the most frequently observed ECG abnormality in patients with massive acute PE.
- Had the best sensitivity (85%), specificity (81%), PPV (93%), and NPV (65%) for massive acute PE
- Correlated highly with a Miller index of >50% (90%) and mean pulmonary artery pressure (PAP) >30 mmHg (81%)
What are some of the common ECG changes seen with right ventricular dysfunction due to acute PE? 2–4
| ECG Changes | RV Dysfunction (%) | Without RV Dysfunction (%) |
| T-Wave Inversion in Leads V1 – V3 | 75 | 5 – 12 |
| RBBB | 30 – 46.4 | 3 – 17 |
| Qr in Lead V1 | 31 | 3 |
| S1Q3T3 | 25 – 35 | 5.5 – 10 |
| Normal ECG | 8 | 49 |
Study methodology: 204 patients enrolled with acute PE
Conclusions:
T-wave inversion in leads V1 – V3 was the most prevalent finding on ECG with right ventricular dysfunction due to acute PE.
- Sensitivity of 75%
- Specificity of 88–95%
- NPV of 86–95.5%
- PPV of 73.1-78%
Summary
In general, the ECG is not very sensitive or specific for acute PE, but T-wave inversions in leads V1 – V3 seem to be the most common ECG finding in massive/submassive acute PE with a diagnostic accuracy of close to 80%.
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