How to treat myocarditis?

Treatment of Myocarditis

Myocarditis should be treated with guideline-directed heart failure therapy, physical rest for 3-6 months, and avoidance of NSAIDs, with immunosuppression reserved only for specific subtypes such as giant cell, cardiac sarcoidosis, or eosinophilic myocarditis. 1

Diagnostic Approach

Before initiating treatment, confirm the diagnosis with:

• Cardiac troponin levels (elevated in myocarditis) 1
• 12-lead ECG (may show ST-segment elevation, arrhythmias) 1
• Standard transthoracic echocardiogram (assess ventricular function) 1
• Cardiac MRI (gold standard for non-invasive diagnosis) 2, 3
• Endomyocardial biopsy (EMB) in specific situations:
  • Patients requiring inotropic support
  • Mechanical circulatory support
  • Mobitz type 2 second-degree or higher heart block
  • Sustained/symptomatic ventricular tachycardia
  • Failure to respond to guideline-based therapy 1

Treatment Algorithm Based on Clinical Stability

For Unstable Patients (Hypotension, Cardiogenic Shock)

1. Transfer to advanced heart failure center 2
2. Consider mechanical circulatory support (including V-A ECMO) for severe cases 1
3. Inotropic support as appropriate 2
4. For those with hemodynamic compromise or MIS-A (multisystem inflammatory syndrome in adults), consider intravenous corticosteroids 1
5. After stabilization, perform CMR before discharge to confirm diagnosis and assess extent of dysfunction 1

For Stable Patients

1. Heart Failure Management:

   • ACE inhibitors for reduced LV ejection fraction 2
   • Low-dose aldosterone antagonists for mildly reduced LV function 1, 2
   • Beta-blockers for hemodynamically stable patients, particularly with supraventricular arrhythmias 1, 2, 4
   • Diuretics for fluid overload 2

2. Anti-inflammatory Treatment:

   • Avoid NSAIDs due to risk of increased inflammation and mortality 1
   • For pericardial involvement with chest pain: consider low-dose colchicine or prednisone 1
   • Immunosuppression (corticosteroids) only for specific subtypes:
     • Giant cell myocarditis
     • Cardiac sarcoidosis
     • Eosinophilic myocarditis 1, 3

3. Physical Activity Restrictions:

   • Avoid strenuous physical activity for 3-6 months 1, 5
   • Competitive sports should be avoided during this period 1
   • Gradual return to activity after:
     • Resolution of cardiopulmonary symptoms
     • Normalization of laboratory evidence of myocardial injury
     • Normalization of LV systolic function
     • Absence of arrhythmias on monitoring and stress testing 2, 5

Special Considerations

For COVID-19 Related Myocarditis

• Patients with concurrent COVID-19 pneumonia requiring oxygen should receive corticosteroids 1
• For MIS-A with acute heart failure/cardiogenic shock, intravenous corticosteroids have shown favorable outcomes 1

For Fulminant Myocarditis

• Management at centers with advanced heart failure expertise 2
• Consider empiric immunosuppressive therapy if biopsy shows severe inflammatory infiltrates 1
• Higher risk of mortality or need for transplant (28% at 60 days) 3

Follow-up and Surveillance

• Perform surveillance testing 3-6 months after presentation:
  • ECG
  • Echocardiogram
  • Ambulatory rhythm monitor
  • Cardiac MRI 1, 2
• Initiate guideline-directed heart failure therapy before discharge and titrate as appropriate in outpatient setting 1

Common Pitfalls to Avoid

1. Inappropriate use of NSAIDs - can worsen inflammation and increase mortality 1
2. Premature return to strenuous activity - can lead to sudden death 1, 5
3. Indiscriminate use of immunosuppression - generally not indicated for acute lymphocytic myocarditis in adults 1
4. Failure to recognize specific subtypes requiring immunosuppression (giant cell, cardiac sarcoidosis, eosinophilic) 1, 3
5. Overuse of beta-blockers in patients with compromised cardiac function - can precipitate cardiogenic shock 1

The overall prognosis varies by severity - approximately 75% of patients have an uncomplicated course with negligible mortality, while those with acute heart failure or ventricular arrhythmias have a 12% rate of in-hospital mortality or need for heart transplant 3.