What is the treatment for viral myocarditis?

Treatment of Viral Myocarditis

All patients with definite viral myocarditis require hospitalization at an advanced heart failure center with guideline-directed heart failure therapy as the cornerstone of treatment, while immunosuppression is generally not indicated for typical lymphocytic viral myocarditis. 1, 2

Immediate Hospitalization and Risk Stratification

Hospitalize all patients with mild or moderate myocarditis at an advanced heart failure center for continuous cardiac monitoring. 1, 2 The only exception is stable patients with chest pain as their sole symptom, preserved left ventricular function, and no ventricular arrhythmias, who may be managed ambulatory with close monitoring. 2

Transfer patients with fulminant myocarditis (cardiogenic shock, sustained ventricular arrhythmias, or advanced atrioventricular block) immediately to centers with mechanical circulatory support capabilities including V-A ECMO. 3, 1 Fulminant myocarditis carries 28% mortality at 60 days despite aggressive treatment, though survivors have better long-term prognosis than non-fulminant forms. 1, 4

Guideline-Directed Heart Failure Therapy

Initiate standard heart failure medications before discharge and titrate in the outpatient setting. 3, 1

• ACE inhibitors or ARBs for neurohormonal blockade in all appropriate patients 1, 2
• Low-dose aldosterone antagonists for patients with mildly reduced left ventricular systolic function and stable hemodynamics 3, 1, 2
• Beta-blockers only if hemodynamically stable and particularly useful for supraventricular arrhythmias 3, 1, 2

Critical caveat: Beta-blockers can precipitate cardiogenic shock in patients with greater cardiac compromise, so avoid in hemodynamically unstable patients. 3, 2

Anti-Inflammatory Therapy: Use Selectively

NSAIDs should be avoided in isolated myocarditis due to increased inflammation and mortality risk in animal models. 1, 2 NSAIDs may only be used when there is associated pericardial involvement to alleviate chest pain and inflammation. 3

Low-dose colchicine or prednisone may be added for persistent chest pain with pericardial involvement, with tapering based on symptoms. 3, 2

Immunosuppressive Therapy: Limited Role

Do not use immunosuppression for typical lymphocytic viral myocarditis. 1, 2 The Myocarditis Treatment Trial found no beneficial effect of prednisone with azathioprine or cyclosporine in biopsy-proven lymphocytic myocarditis. 3

Immunosuppression is reserved for specific subtypes only: 1, 2

• Giant cell myocarditis
• Cardiac sarcoidosis
• Eosinophilic myocarditis

Empiric corticosteroids may be considered in fulminant myocarditis with biopsy evidence of severe myocardial inflammatory infiltrates or in patients with hemodynamic compromise, balanced against infection risk. 3, 2

Mechanical Circulatory Support

Initiate mechanical circulatory support urgently if shock does not reverse rapidly with pharmacological therapy. 1 Options include percutaneous cardiopulmonary support, ECMO, or intra-aortic balloon pump. 1

Arrhythmia Management

Manage arrhythmias supportively as they typically resolve with resolution of acute inflammation. 1, 2 Acute arrhythmias are frequent in viral myocarditis and account for a large proportion of sudden cardiac deaths in young people. 5

Insert a temporary pacemaker for symptomatic or high-grade AV block that triggers ventricular tachyarrhythmias. 1

Mandatory Activity Restriction

Mandate complete exercise abstinence for 3-6 months after diagnosis. 3, 1, 2 Sustained aerobic exercise during acute viral myocarditis increases mortality in animal models and can cause sudden death. 1, 2

Competitive sport participation must be avoided for the entire 3-6 month period. 1, 2

Follow-Up Surveillance

Perform follow-up testing at 3-6 months after presentation including ECG, echocardiogram, ambulatory rhythm monitor, and cardiac MRI. 3, 1, 2 This surveillance is essential to gauge recovery of cardiac function and inflammation, guide heart failure management, and assess prognosis. 3

For patients who had cardiogenic shock or hemodynamic instability, perform cardiac MRI before hospital discharge to confirm diagnosis and assess extent of ventricular dysfunction and inflammation. 3, 2

Monitor for development of dilated cardiomyopathy, which occurs in 21% of patients during long-term follow-up. 1

Common Pitfalls to Avoid

• Do not use NSAIDs routinely in isolated myocarditis without pericardial involvement 1, 2
• Do not initiate beta-blockers in hemodynamically compromised patients 2
• Do not use empiric immunosuppression for typical lymphocytic viral myocarditis 1, 2
• Do not allow early return to exercise before the 3-6 month restriction period and proper reassessment 1, 2