ECG in suspected pulmonary embolism.

Area of Science:

• Cardiology
• Diagnostic Imaging
• Pulmonary Medicine

Background:

• Pulmonary embolism (PE) is a critical condition requiring accurate diagnosis.
• Electrocardiogram (ECG) is a readily available tool, but its diagnostic value for PE is debated.
• Specific ECG changes have been anecdotally linked to PE, but their predictive accuracy needs validation.

Purpose of the Study:

• To evaluate the diagnostic utility of specific ECG abnormalities for suspected pulmonary embolism (PE).
• To determine the sensitivity and specificity of ECG findings in identifying PE.
• To assess the predictive value of ECG changes in relation to PE clot burden.

Main Methods:

• Retrospective case-control study involving 189 patients with confirmed PE and 189 controls with suspected PE.
• Patients were matched for age, and ECGs were analyzed for eight prespecified features.
• Analysis was stratified based on large and small clot loads in PE patients.

Main Results:

• Normal ECGs were observed in 20-25% of PE patients, including those with large clot loads.
• Right ventricular (RV) strain pattern showed significant association with PE (11.1% vs 2.6%, OR 4.58).
• RV strain was more prevalent in PE patients with large clot loads (17.1% vs 2.6%, OR 7.55), demonstrating high specificity (97.4%).

Conclusions:

• An ECG demonstrating RV strain in a breathless patient is highly indicative of PE.
• Commonly cited ECG changes like S1Q3T3 and P pulmonale are infrequent in PE.
• Only the RV strain pattern on ECG holds significant predictive value for diagnosing PE.