What syndrome can occur as a complication of myocardial infarction?

Post-Myocardial Infarction Pericardial Syndromes

Two distinct pericardial syndromes can complicate myocardial infarction: early post-infarction pericarditis (occurring within days) and Dressler syndrome (occurring 1-2 weeks or later after MI). 1, 2, 3

Early Post-Infarction Pericarditis

This syndrome typically develops 2-3 days after acute MI and is now rare (<5-6% incidence) in the primary percutaneous coronary intervention era, occurring mainly after delayed or failed reperfusion. 1, 3, 4

Clinical Presentation

• Sharp, pleuritic chest pain that worsens with inspiration and improves when sitting forward 1
• Pain distinguished from recurrent ischemia by its postural and respiratory relationship 1
• Pericardial friction rub on examination (though may be absent) 1, 4
• Associated with larger infarct size 1, 3

Diagnostic Approach

• ECG changes are typically overshadowed by infarction changes, though ST segments may remain elevated with persistent upright T waves 1
• Echocardiography is mandatory to assess for pericardial effusion, particularly to identify effusions >10 mm thickness which require urgent investigation for subacute ventricular rupture 1, 3
• Two-thirds of patients with effusions >10 mm may progress to tamponade or free-wall rupture 3

Management Strategy

• Most cases are self-limited and require only supportive care; anti-inflammatory therapy is reserved for patients with persistent symptoms 1, 3
• Aspirin plus colchicine is first-line therapy when treatment is needed 1, 2, 3
• Aspirin dosing: 500-1,000 mg every 6-8 hours (total 1.5-4 g/day) 2
• Colchicine dosing: 0.5-0.6 mg once or twice daily for 3 months 2
• Other NSAIDs (except ibuprofen) should be avoided as they may thin the infarct zone; ibuprofen is acceptable only when aspirin cannot be used 3
• Hospital admission is mandatory to monitor for tamponade and adjust treatment 3

Dressler Syndrome (Late Post-MI Pericarditis)

Dressler syndrome occurs 1-2 weeks to several months after MI and is extremely rare (<1%) in the primary PCI era, reflecting larger infarct size or late reperfusion. 1, 2, 3, 5, 6

Clinical Features

• Pleuritic chest pain, low-grade fever, and malaise 5, 7
• Pericardial and/or pleural effusions on imaging 7
• Elevated inflammatory markers 5
• Latent period of several weeks to months after MI is possible 8

Pathophysiology

• Auto-antibodies targeting antigens exposed after cardiac tissue damage 7
• Represents a form of post-cardiac injury syndrome (PCIS) 7

Treatment Protocol

• Aspirin plus colchicine using the same regimen as for other post-cardiac injury pericarditis 1, 2, 3
• Aspirin: 500-1,000 mg every 6-8 hours (range 1.5-4 g/day) 2
• Colchicine: 0.5 mg twice daily if ≥70 kg or 0.5 mg once daily if <70 kg for at least 6 months 2
• Colchicine reduces recurrence rates by approximately 50% 2
• Gradual tapering is essential: decrease aspirin by 250-500 mg every 1-2 weeks, taper one drug at a time, then gradually discontinue colchicine over several months 2

Refractory Cases

For patients unresponsive to first-line therapy:

• Short-term corticosteroid therapy (3-6 months) may be used with caution 2, 3
• Systemic corticosteroids should be avoided when possible due to risk of delayed myocardial healing 3
• Alternative: intrapericardial triamcinolone (300 mg/m²) via pericardiocentesis 2, 3

Critical Pitfalls to Avoid

• Do not mistake pericarditic chest pain for recurrent MI or unstable angina—careful history focusing on sharp quality, postural changes, and respiratory variation is essential 1, 4
• Never dismiss pericardial effusions >10 mm—these require urgent evaluation for subacute rupture 1, 3
• Avoid non-aspirin NSAIDs (except ibuprofen) in the post-MI setting due to infarct zone thinning risk 3
• Do not use corticosteroids as first-line therapy—they delay myocardial healing and should be reserved for refractory cases 3

Prognosis

• Despite association with larger infarct size, in-hospital and 1-year mortality rates are similar between patients with and without post-MI pericarditis 1, 3
• Most cases follow a benign course, though relapsing patterns can occur 7
• Rare complications include hemopericardium, cardiac tamponade (<2%), and constrictive pericarditis (3% of cases) 1, 4
• Serial C-reactive protein measurements can guide treatment duration and assess therapeutic response 3