What is the treatment for myocarditis?

Treatment of Myocarditis

All patients with definite myocarditis should be hospitalized at an advanced heart failure center and treated with guideline-directed medical therapy for heart failure, while immunosuppression is reserved only for specific subtypes including giant cell myocarditis, cardiac sarcoidosis, eosinophilic myocarditis, or immune checkpoint inhibitor-induced disease. 1, 2

Immediate Hospitalization and Risk Stratification

• Hospitalize all patients with mild or moderate myocarditis at an advanced heart failure center to ensure immediate access to mechanical circulatory support if clinical deterioration occurs 1, 2
• Transfer patients with fulminant myocarditis immediately to centers with ECMO or percutaneous cardiopulmonary support capabilities, as this presentation carries 28% mortality at 60 days despite aggressive treatment 1, 2
• Fulminant myocarditis paradoxically has better long-term prognosis than non-fulminant forms if patients survive the acute phase 1, 2

Standard Medical Therapy

Initiate guideline-directed heart failure therapy before discharge according to current systolic heart failure guidelines 3, 2, 4:

• ACE inhibitors or ARBs for neurohormonal blockade in all patients with systolic blood pressure >100 mmHg 1, 2
• Beta-blockers only if hemodynamically stable, particularly for patients with supraventricular arrhythmias; avoid in overt heart failure with pulmonary congestion or low cardiac output 1, 2, 4
• Aldosterone antagonists for patients with mildly reduced left ventricular function and stable hemodynamics 1, 2, 4

Mechanical Circulatory Support

• Initiate mechanical circulatory support urgently if cardiogenic shock does not reverse rapidly with pharmacological therapy 3, 4
• Options include ECMO, percutaneous cardiopulmonary support, or intra-aortic balloon pump 4
• Some patients can be bridged to recovery with mechanical support 3

Immunosuppression: When NOT to Use

Immunosuppression is generally NOT indicated for acute lymphocytic myocarditis in adults based on individual trials and meta-analyses, including the underpowered American Myocarditis Treatment Trial 3, 1, 4

Immunosuppression: When TO Use

Use immunosuppressive therapy only in these specific circumstances 3, 1, 2:

• Giant cell myocarditis
• Cardiac sarcoidosis
• Eosinophilic myocarditis
• Immune checkpoint inhibitor-induced myocarditis: permanently discontinue immunotherapy and start high-dose methylprednisolone 1, 2

For immune checkpoint inhibitor myocarditis specifically, high-dose corticosteroids result in better treatment response, with lower-dose steroids associated with elevated troponin and higher rates of major adverse cardiac events 1

Medications to AVOID

Avoid nonsteroidal anti-inflammatory drugs because of the risk of increased inflammation and mortality in myocarditis 3

Arrhythmia Management

• Acute arrhythmias often resolve with resolution of inflammation; management is supportive 3, 1, 2
• Insert temporary pacemaker if symptomatic or high-grade AV block triggers ventricular tachyarrhythmias 1, 2
• For drug-refractory ventricular arrhythmias after myocarditis, endocardial and epicardial radiofrequency catheter ablation can be effective 3

Activity Restriction

Mandate complete exercise abstinence and avoid competitive sport participation for 3-6 months after diagnosis 3, 1, 2, 4

This recommendation is based on animal models showing that sustained aerobic exercise during acute viral myocarditis leads to increased mortality and can lead to sudden death 3

Reassess with clinical evaluation and functional testing before resuming competitive sports 3, 1

Follow-Up Surveillance

Perform follow-up testing 3-6 months after presentation to assess recovery 1, 2, 4:

• Repeat echocardiography or cardiac MRI to assess ventricular function 1, 2
• Reassess cardiac biomarkers 1, 2
• Monitor for development of dilated cardiomyopathy, which occurs in 21% of patients during long-term follow-up 1, 2

Cardiac Transplantation

• The overall rate of survival after cardiac transplantation for adult patients with myocarditis is similar to that for other causes of cardiac failure 3, 4
• Recent data suggest higher post-transplantation risk in children if active myocarditis is present in the explanted heart 3

Common Pitfalls to Avoid

• Do not use empiric immunosuppression for typical lymphocytic myocarditis – this is not supported by evidence and may cause harm 3, 1
• Do not prescribe NSAIDs for chest pain relief – these increase inflammation and mortality 3
• Do not allow patients to return to competitive sports without formal reassessment at 3-6 months – premature exercise can cause sudden death 3, 1
• Do not discharge patients with new-onset myocarditis to community hospitals – they require advanced heart failure center capabilities 1, 2