• True incidence of pericarditis unknown: 5% of non-ACS “chest pain” ED visits.
• Cardiac tamponade can occur in up to 15% of cases.
• Important to distinguish from ACS.
• Inflammatory condition of the pericardium:
  • Infectious etiologies
    • Most common cause is viral or idiopathic as etiologic agent is rarely identified.
    • Consider tuberculosis if recent travel to an endemic region.
  • Non-infectious etiologies
    • Autoimmune conditions – SLE, RA, scleroderma, sarcoid, vasculitis.
    • Autoinflammatory pericardial syndromes (Dressler syndrome): post myocardial infarction, cardiac surgery or cardiac trauma.
    • Neoplastic: (metastatic: lung>breast>leukaemia and lymphoma>melanoma).
    • Radiation.
    • Metabolic (uremia).
    • Drug-related.
  • Symptoms usually last 4-6 weeks but other forms exist
    • Incessant pericarditis: up to 3 months.
    • Recurrent/relapsing pericarditis: symptoms recur after a symptom-free period.
    • Chronic pericarditis: symptoms > 3 months.

History

• Quick onset, sharp chest pain:
  • Pleuritic – worse on inspiration
  • Improves with sitting and leaning forward
  • May radiate to neck, back, shoulder and/or jaw
• May be preceded by a gastrointestinal or “flu-like” syndrome.

Physical Examination

• Tachycardic, tachypneic, fever
• Friction rub highly specific but only present in 30% of cases
  • Can fluctuate hourly.
  • Heard best at end expiration, with the patient leaning forward.

ECG

• There are four stages of ECG evolution in pericarditis, all of which are found in 60% of cases (figure 1).
  • Stage 1 (hours to days): Diffuse ST elevation and PR depression, ST depression in aVR only
  • Stage 2 (within first week): ST and PR segments normalize
  • Stage 3: Diffuse T wave inversion and ECG otherwise normal
  • Stage 4: T waves return to normal (May have indefinite persistence of T wave inversion)

Created By Ella Barrett-Chan, MSI UBC

• Pericarditis features that differentiate it from ACS:
  • ST elevation is ‘concave’ up but typically ‘convex’ up in ACS (figure 2)
  • Down sloping T-P segments (“Spodick sign”)
  • Absence of pathologic Q waves
  • Absence of reciprocal ST changes
  • Absence of QRS widening and QT prolongation in leads with ST elevation

Created By Ella Barrett-Chan, MSI UBC

• Differentiating pericarditis from benign early repolarization (BER)
  • ST elevation is less than 25% of T-wave amplitude in BER
  • ECG findings are stable over time in BER
  • No PR depression in BER

Figure 3. Comparison of ECG changes in acute pericarditis, ST elevation MI and benign early repolarization.

Laboratory Findings

• WBC, CRP and ESR are likely to be elevated.
• Troponin may be elevated in 30% – concomitant myocarditis.

Imaging

• CXR typically normal
  • Large pericardial effusion is uncommon – cardiomegaly.
• Transthoracic echocardiography
  • Pericardial effusion in up to 60% of cases, often mild.
  • Wall motion abnormalities suggest ACS rather than pericarditis.

• Diagnosis of acute pericarditis requires at least two of the four main clinical criteria:
  • Typical chest pain (> 85% cases).
  • Pericardial friction rub (up to 30% cases).
  • New widespread ST elevation or PR depression (up to 60% cases).
  • Pericardial effusion (up to 60% cases).
• Supportive findings for diagnosis include: elevated inflammatory markers, evidence of pericardial inflammation through CT or CMR (not an ED issue).
• Diagnostic pericardiocentesis may be considered by cardiology, internal medicine.

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2. Doctor NS, Shah AB, Coplan N, Kronzon I. Acute Pericarditis. Prog Cardiovasc Dis. 2017;59(4):349-359. doi:10.1016/j.pcad.2016.12.001

   
   

3. Imazio M, Gaita F. Diagnosis and treatment of pericarditis. Heart. 2015;101(14):1159-1168. doi:10.1136/heartjnl-2014-306362

   
   

4. Abdushi S, Veseli A, Abdushi S, Zenelaj F. Differential Diagnosis of ST segment elevation on ECG. UBT Conf Present. 2017;(October 2017). doi:10.33107/ubt-ic.2017.291

   
   

5. Chiabrando JG, Bonaventura A, Vecchié A, et al. Management of Acute and Recurrent Pericarditis: JACC State-of-the-Art Review. J Am Coll Cardiol. 2020;75(1):76-92. doi:10.1016/j.jacc.2019.11.021

   
   

6. Rossello X, Wiegerinck RF, Alguersuari J, et al. New electrocardiographic criteria to differentiate acute pericarditis and myocardial infarction. Am J Med. 2014;127(3):233-239. doi:10.1016/j.amjmed.2013.11.006