What are the ECG findings and treatment options for a patient with pericarditis?

ECG Findings and Treatment of Pericarditis

ECG Findings in Acute Pericarditis

The classic ECG finding in acute pericarditis is widespread ST-segment elevation (concave upward) with PR-segment depression, though these changes appear in only 25-60% of cases. 1

Key ECG Characteristics

• ST-segment elevation: Widespread, concave upward pattern affecting multiple leads without reciprocal ST depression 2, 3
• PR-segment depression: Present in multiple leads, highly specific when present 2, 3
• T-wave changes: May develop T-wave inversions as the disease evolves 3
• Absence of reciprocal changes: Unlike myocardial infarction, pericarditis shows no reciprocal ST depression 3

Critical Diagnostic Pitfalls

ECG changes may be completely absent in 40-75% of pericarditis cases, and a normal ECG does not exclude the diagnosis. 4, 5 The ECG can be normal at initial presentation or for days after symptom onset, requiring serial ECGs to capture evolving changes 4. ECG changes are temporally dynamic and influenced by disease severity, timing of presentation, degree of myocardial involvement, and treatment initiation 4.

When ECG changes are present, they suggest concurrent myocardial involvement (myopericarditis) rather than isolated pericarditis, since the pericardium itself is electrically silent. 1, 5 ECG abnormalities correlate with troponin elevation and indicate epicardial inflammation 5.

Differential Diagnosis

The major ECG differential is ST-elevation myocardial infarction (STEMI) 1. Key distinguishing features:

• Pericarditis: widespread ST elevation, concave upward, no reciprocal changes, PR depression 3, 6
• STEMI: localized ST elevation, convex upward, reciprocal ST depression in opposite leads 7

Diagnostic Criteria

Diagnosis requires at least 2 of 4 criteria: (1) pericarditic chest pain, (2) pericardial friction rub, (3) new widespread ST-elevation or PR depression on ECG, (4) new or worsening pericardial effusion. 1, 2, 3

Clinical Features to Identify

• Chest pain: Sharp, retrosternal or left precordial, pleuritic quality, radiates to trapezius ridge, improves sitting forward, worsens with inspiration 2, 3
• Pericardial friction rub: Mono-, bi-, or triphasic scratching sound on auscultation, highly specific but transient, present in only 18-30% of cases 3, 6
• Pericardial effusion: Detected on echocardiography 1, 2

Mandatory Diagnostic Workup

• ECG: Recommended in all suspected cases (Class I) 1
• Transthoracic echocardiography: Recommended in all cases to assess effusion size and detect tamponade (Class I) 1, 2, 3
• Chest X-ray: Recommended in all cases, though typically normal unless effusion exceeds 300 mL (Class I) 1, 2
• Inflammatory markers: CRP, ESR, and white blood cell count to confirm inflammation and monitor treatment response (Class I) 1, 2
• Cardiac biomarkers: Troponin and creatine kinase to assess for myocardial involvement (Class I) 1, 2

Treatment Algorithm

Risk Stratification (Determines Inpatient vs Outpatient Management)

High-risk features requiring hospital admission: 2, 3

• Fever >38°C (100.4°F)
• Subacute onset (symptoms developing over days)
• Large pericardial effusion (>20 mm on echo)
• Cardiac tamponade
• Failure to respond to NSAIDs within 7 days
• Elevated cardiac biomarkers suggesting myopericarditis

Low-risk patients can be managed as outpatients with empiric anti-inflammatory therapy and 1-week follow-up (Class I, Level B). 1, 3

First-Line Treatment

NSAIDs at full anti-inflammatory doses until symptom resolution and CRP normalization: 3, 6

• Ibuprofen 600-800 mg three times daily, OR
• Aspirin 750-1000 mg three times daily

PLUS Colchicine 0.5 mg twice daily (or 0.5 mg once daily if <70 kg) for 3 months to reduce recurrence risk. 3, 6

Treatment Duration and Monitoring

• Continue NSAIDs until symptoms resolve and CRP normalizes 3
• Taper medications gradually only after symptom resolution and CRP normalization 3
• Mandatory follow-up at 1 week to assess treatment response (Class I, Level B) 1, 3
• Exercise restriction until symptom resolution and CRP normalization 3

Second-Line Treatment

Low-dose corticosteroids reserved ONLY for: 3, 6

• Contraindications to NSAIDs and colchicine
• Pregnancy beyond 20 weeks gestation
• Systemic inflammatory conditions requiring steroids

Avoid glucocorticoids as first-line therapy—they significantly increase recurrence risk. 3

Critical Treatment Caveats

• Avoid NSAIDs in post-myocardial infarction pericarditis, as they impair myocardial healing 3
• Do not administer reperfusion therapy if pericarditis is misdiagnosed as STEMI—this causes adverse effects 7
• Normal inflammatory markers do not exclude pericarditis, especially if anti-inflammatory treatment already started 2
• Pericardiocentesis indicated only for tamponade, suspected bacterial/neoplastic pericarditis, or symptomatic large effusions not responding to medical therapy 2