What are the EKG findings and treatment for pericarditis?

ECG Findings and Treatment for Pericarditis

The classic ECG findings in acute pericarditis include widespread ST-segment elevation (concave upward), PR-segment depression, and absence of reciprocal changes, occurring in up to 60% of cases. 1

Diagnostic ECG Findings

• Widespread ST-segment elevation with concave upward morphology (unlike the convex pattern seen in myocardial infarction) 1, 2

• PR-segment depression (opposite to P wave polarity) - a highly specific finding that helps differentiate from STEMI 1, 3

• Absence of reciprocal ST depression (except in aVR) - an important distinguishing feature from acute coronary syndromes 2, 4

• Temporal evolution of ECG changes through four stages: 1

  • Stage I: Diffuse concave ST elevation with PR depression
  • Stage II: ST segments return to baseline, PR remains deviated
  • Stage III: T wave flattening and inversion
  • Stage IV: Normalization of ECG (may not occur in all patients)

• ECG changes may be absent in up to 40% of cases, especially early in the disease course 5

• PR depression in both precordial and limb leads has high predictive value (96.7% positive predictive value) for differentiating myopericarditis from STEMI 3

Important Diagnostic Considerations

• Diagnosis requires at least 2 of 4 criteria: pericarditic chest pain, pericardial friction rub, ECG changes, and pericardial effusion 1, 2
• ECG changes reflect epicardial inflammation rather than parietal pericardial involvement, as the pericardium itself is electrically inert 1
• Serial ECGs may be necessary as changes can be dynamic and evolve rapidly during the course of disease 5
• Echocardiography is essential in all patients with suspected pericarditis to detect effusion and evaluate for complications 1, 2

Differential Diagnosis Pitfalls

• Early repolarization pattern can mimic pericarditis but typically has J-point elevations with a slur/notch at the end of QRS 1
• Left circumflex artery occlusion can sometimes produce PR depression with multilead ST elevation, mimicking pericarditis 6
• QRS widening and QT interval shortening in leads with ST elevation favor STEMI over pericarditis 6
• Myopericarditis may show elevated cardiac biomarkers (troponin, CK-MB) in addition to ECG changes 1, 2

Treatment Algorithm

1. First-line therapy: NSAIDs at full anti-inflammatory doses until symptom resolution 1, 2

   • Ibuprofen or aspirin are preferred options
   • Continue until complete symptom resolution and normalization of inflammatory markers

2. Add colchicine (0.5 mg twice daily or 0.5 mg daily for patients <70 kg) for 3 months 2

   • Reduces risk of recurrence
   • Should be used in combination with NSAIDs

3. Exercise restriction until symptoms resolve and CRP normalizes 2

4. Follow-up evaluation after 1 week to assess treatment response 1, 2

5. For high-risk patients or those with contraindications to NSAIDs/colchicine:

   • Consider hospitalization if high-risk features present (fever >38°C, subacute onset, large effusion, tamponade, or failure to respond to NSAIDs) 2
   • Low-dose corticosteroids only after excluding infectious causes 2

Important Treatment Considerations

• Avoid glucocorticoids as first-line therapy as they increase risk of recurrence 2
• Avoid NSAIDs in post-myocardial infarction pericarditis as they may impair myocardial healing 2
• Taper medications gradually only after symptoms resolve and inflammatory markers normalize 2
• Patients with myopericarditis (elevated cardiac biomarkers) may require additional monitoring 1