What is the treatment for viral myocarditis?

Treatment of Viral Myocarditis

Treatment of viral myocarditis is primarily supportive with guideline-directed heart failure therapy, while immunosuppression is generally NOT indicated for acute lymphocytic myocarditis but should be considered for specific subtypes including giant cell myocarditis, cardiac sarcoidosis, or eosinophilic myocarditis. 1

Initial Risk Stratification and Hospitalization

All patients with definite myocarditis (mild or moderate severity) require hospitalization, ideally at an advanced heart failure center. 1 The severity determines the level of care:

• Fulminant myocarditis (cardiogenic shock, sustained ventricular arrhythmias, advanced AV block) requires management at centers with expertise in advanced heart failure, mechanical circulatory support including V-A ECMO, and transplant capabilities 1
• Stable patients with chest pain as the only symptom, preserved LV function, and no ventricular arrhythmias can be managed in the ambulatory setting with close monitoring 1

Supportive Medical Therapy

Heart Failure Management

Treatment should follow standard heart failure pathways unrelated to the viral etiology. 1 The specific approach includes:

• Guideline-directed medical therapy for heart failure should be initiated before discharge and titrated in the outpatient setting 1
• Low-dose aldosterone system inhibitors may be used empirically in patients with mildly reduced LV systolic function and stable hemodynamics 1
• Beta-blockers may be helpful in patients with supraventricular arrhythmias if hemodynamically stable, but can precipitate cardiogenic shock in patients with greater cardiac compromise 1

Anti-Inflammatory Therapy

For patients with associated pericardial involvement, nonsteroidal anti-inflammatory drugs may be used to alleviate chest pain and inflammation 1. However, NSAIDs should generally be avoided in isolated myocarditis due to risk of increased inflammation and mortality in animal models 1.

• Low-dose colchicine or prednisone may be added for persistent chest pain, with tapering based on symptoms and clinical findings 1

Immunosuppressive Therapy: When to Use

The role of immunosuppression is highly selective and etiology-dependent:

Indications for Immunosuppression

• Giant cell myocarditis: Immunotherapy improves survival and should be considered 1, 2
• Cardiac sarcoidosis: Immunosuppression is indicated 1
• Eosinophilic myocarditis: Corticosteroids are appropriate 1, 2
• Fulminant myocarditis with biopsy evidence of severe myocardial inflammatory infiltrates: Empiric corticosteroids may be considered, balanced against infection risk 1
• Hemodynamic compromise or MIS-A (multisystem inflammatory syndrome in adults): IV corticosteroids may be considered 1

When NOT to Use Immunosuppression

Individual trials and meta-analyses demonstrate that immunosuppression is generally NOT indicated for acute lymphocytic myocarditis in adults. 1 This represents the most common form of viral myocarditis and routine immunosuppression has not shown benefit 2, 3.

Activity Restriction

Competitive sport participation and strenuous physical activity must be avoided for 3-6 months after diagnosis. 1 This is critical because:

• Sustained aerobic exercise during acute viral myocarditis leads to increased mortality in animal models and can cause sudden death 1
• Reassessment with clinical evaluation and functional testing is required before resuming competitive sports 1

Mechanical Circulatory Support

For patients developing cardiogenic shock despite optimal medical management, mechanical circulatory support may be required 1. Some patients can be bridged to recovery, though the role of immunosuppression in patients requiring MCS remains uncertain 1.

Follow-Up and Surveillance

Follow-up surveillance testing is essential in all patients with myocarditis and should include: 1

• ECG, echocardiogram, ambulatory rhythm monitor, and CMR at 3-6 months after presentation
• Particularly important in those with ongoing cardiac symptoms or findings suggestive of significant myocardial involvement 1
• CMR should be performed before hospital discharge in patients who had cardiogenic shock or hemodynamic instability to confirm diagnosis and assess extent of dysfunction 1

Arrhythmia Management

Acute arrhythmia management is supportive, as arrhythmias often resolve with resolution of acute inflammation 1. For patients with drug-refractory ventricular arrhythmias after myocarditis, endocardial and epicardial radiofrequency catheter ablation can be effective 1.

Common Pitfalls to Avoid

• Do not use NSAIDs routinely in isolated myocarditis without pericardial involvement due to increased inflammation risk 1
• Do not initiate beta-blockers in hemodynamically compromised patients as they can precipitate cardiogenic shock 1
• Do not use empiric immunosuppression for typical lymphocytic viral myocarditis, as it has not demonstrated benefit and increases infection risk 1, 2
• Do not allow early return to exercise before the 3-6 month restriction period and proper reassessment 1