II. Epidemiology

  1. Post-MI Pericarditis Incidence has fallen with the advent of cardiac interventions for Acute Coronary Syndrome

III. Pathophysiology

  1. Post-MI Pericarditis arises from an immune response to Antigens (antimyosin, antiheart) from injured Myocardium
  2. Pericarditis represents one part of a Constellation of post-MI syndrome complications

IV. Types

  1. Early Post-MI Pericarditis (1 to 6% of acute MI patients)
    1. Onset within the first few days of Myocardial Infarction
    2. Arises from localized inflammation from Myocardium injured by infarction
    3. Typically benign course and resolves spontaneously
  2. Late Post-MI Pericarditis or Dressler Syndrome (<1% of MI patients)
    1. Onset weeks to months after Myocardial Infarction
    2. Abnormal, persistent inflammation that extends beyond the time of MI recovery
    3. Typically symptomatic with a more complicated course (Pericardial Effusions or Cardiac Tamponade)

V. Risk Factors

  1. Large Myocardial Infarction
  2. Delayed MI presentation
  3. Failed percutaneous intervention

VI. Labs

  1. Serum Troponin
    1. Elevations from acute MI will be difficult to distinguish from Myocarditis
  2. Inflammatory markers (e.g. C-RP, ESR, Leukocytosis)
    1. Often elevated in both Myocardial Infarction and Pericarditis

VII. Diagnostics

  1. See EKG in Pericarditis
  2. See EKG in Acute Coronary Syndrome
  3. Electrocardiogram
    1. May be difficult to distinguish post-MI and reperfusion findings from Pericarditis related EKG changes

VIII. Imaging

  1. Echocardiogram
    1. Identifies Pericardial Effusion and Cardiac Tamponade
  2. Cardiac MRI
    1. Identifies findings consistent with Pericarditis
      1. Pericardium thickening or edema
      2. Pericardium delayed clearance of contrast
    2. Identifies Myocardial Infarction (MI) complications
      1. Extent and timing of MI
      2. Ventricular Scar
      3. Cardiomyopathy
      4. Ventricular aneurysm

IX. Findings

  1. See Pericarditis
  2. Similar Pericarditis symptoms and signs, in the context of recent Myocardial Infarction

X. Management

  1. Optimize Management of Acute Coronary Syndrome
    1. Acute MI management (e.g. reperfusion) takes precedence over Pericarditis management
  2. Aspirin
    1. First-line therapy for Post-Myocardial Infarction Pericarditis (or Pericarditis and known Coronary Artery Disease)
    2. Aspirin 650-1000 mg every 6-8 hours for 7-10 days and then tapered over 4 weeks
  3. Colchicine
    1. Indicated in Pericarditis refractory to Aspirin
    2. See Colchicine for adverse effects and lab monitoring
    3. Dosing
      1. Start 1-2 mg on day 1 and then 0.5 to 1 mg/day for 3 months (divided dosing)
      2. Weight > 70 kg (154 lb): 0.5 mg twice daily
      3. Weight <70 kg (154 lb): 0.5 mg once daily
      4. Colchicine weaned after CRP drops to <3
  4. Medications to Avoid In Post-MI Pericarditis (contrast with non-MI related Pericarditis)
    1. Avoid NSAIDs
      1. Delay myocardial healing
      2. Indomethacin decreases coronary Blood Flow
    2. Avoid Corticosteroids
      1. Delay myocardial healing and weaken the Myocardium
      2. Risk of myocardial rupture or ventricular aneurysm

XI. Complications

  1. See Pericarditis
  2. Cardiac Tamponade
  3. Constrictive Pericarditis
  4. Recurrent Post-MI Pericarditis (10-15% of cases)
    1. Differentiate from recurrent Acute Coronary Syndrome

XII. References

  1. Klasek and Alblaihed (2023) Crit Dec Emerg Med 37(6): 4-11
  2. Verma (2020) Curr Cardiol Rep 22(10): 127 [PubMed]

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