What is the treatment for myocarditis?

Myocarditis Treatment

All patients with definite myocarditis should be hospitalized, ideally at an advanced heart failure center, and treated with guideline-directed medical therapy for heart failure, while immunosuppression is generally NOT indicated except for specific subtypes like giant cell myocarditis, cardiac sarcoidosis, or eosinophilic myocarditis. 1, 2

Immediate Hospitalization and Risk Stratification

• Hospitalize all patients with mild or moderate myocarditis at an advanced heart failure center 3, 1
• Transfer patients with fulminant myocarditis (hemodynamic instability, cardiogenic shock, or refractory arrhythmias) to centers with expertise in mechanical circulatory support 3, 1, 2
• Fulminant myocarditis carries 28% mortality at 60 days despite aggressive treatment, but paradoxically has better long-term prognosis than non-fulminant forms if patients survive the acute phase 2, 4

Standard Medical Therapy (First-Line for All Patients)

Initiate guideline-directed heart failure therapy before discharge and titrate in outpatient setting: 3, 1, 2

• ACE inhibitors or ARBs for neurohormonal blockade (start with low doses like captopril 1-6.25 mg if systolic BP >100 mmHg) 2, 4
• Beta-blockers for patients with supraventricular arrhythmias, but ONLY if hemodynamically stable—avoid in overt heart failure with pulmonary congestion or low output 1, 2, 4
• Aldosterone antagonists for patients with mildly reduced left ventricular function and stable hemodynamics 1

Critical Pitfall: Avoid NSAIDs

• Do NOT use NSAIDs for chest pain in myocarditis (except when pericardial involvement is suspected), as they increase inflammation and mortality in animal models 3
• For pericardial involvement specifically, NSAIDs, colchicine, and/or prednisone are reasonable 3

Mechanical Circulatory Support for Severe Cases

For patients with cardiogenic shock despite optimal medical management: 3, 1, 2

• Start inotropic support (dopamine 5 mcg/kg/min, titrate up to 20-50 mcg/kg/min based on response) 4
• Initiate mechanical circulatory support urgently if shock does not reverse rapidly with pharmacological therapy 4
• Options include percutaneous cardiopulmonary support, ECMO, or intra-aortic balloon pump 2, 4
• Some patients can be bridged to recovery; cardiac transplantation survival rates are similar to other causes of heart failure 3, 1

Immunosuppression: Only for Specific Subtypes

Immunosuppression is generally NOT indicated for acute lymphocytic myocarditis in adults (the most common form), as individual trials and meta-analyses show no benefit 3, 1, 2

When to Use Immunosuppression:

Consider immunosuppressive therapy in these specific circumstances: 3, 1, 2

• Giant cell myocarditis (requires immunosuppression)
• Cardiac sarcoidosis (requires immunosuppression)
• Eosinophilic myocarditis (requires immunosuppression)
• COVID-19 myocarditis with hemodynamic compromise or MIS-A: IV corticosteroids may be considered 3
• COVID-19 myocarditis with pneumonia requiring supplemental oxygen: treat with corticosteroids 3, 1
• Biopsy-proven severe myocardial inflammatory infiltrates or fulminant myocarditis: empiric corticosteroids may be considered, balanced against infection risk 3, 1

For immune checkpoint inhibitor-induced myocarditis (grade 3-4): 2

• Permanently discontinue the immunotherapy
• Start high-dose methylprednisolone 1 mg/kg IV immediately
• Continue for several days until improvement to grade ≤1
• Mortality remains high at 23% despite rapid treatment

Arrhythmia Management

• Acute arrhythmias often resolve with resolution of inflammation—management is supportive 3
• Continuous ECG monitoring is essential 4
• Insert temporary pacemaker if symptomatic or high-grade AV block triggers ventricular tachyarrhythmias 4
• Consider permanent pacemaker if AV block persists 4
• For drug-refractory ventricular arrhythmias after myocarditis, endocardial and epicardial radiofrequency catheter ablation can be effective 3

Activity Restriction

Mandate complete exercise abstinence for 3-6 months after diagnosis 3, 1

• Sustained aerobic exercise during acute viral myocarditis increases mortality in animal models and can cause sudden death 3
• Competitive sport participation should be avoided for 3-6 months 3, 1
• Before resuming competitive sports, reassess with: 3
  • Absence of cardiopulmonary symptoms
  • Resolution of laboratory evidence of myocardial injury
  • Normalization of LV systolic function
  • Absence of spontaneous/inducible cardiac arrhythmias on ECG monitoring and exercise stress testing

Follow-Up Surveillance

Perform follow-up testing 3-6 months after presentation to assess recovery: 1, 2

• Repeat echocardiography or cardiac MRI to assess ventricular function 2
• Reassess cardiac biomarkers 2
• Clinical evaluation and functional testing before resuming competitive activities 3
• Dilated cardiomyopathy develops in 21% of patients during long-term follow-up 2