Expert Consensus Pathway for Myocarditis Management: A Comprehensive Guide by the ACC

 A new expert consensus decision pathway from the American College of Cardiology (ACC) provides comprehensive guidance on the management of myocarditis, covering aspects from diagnosis to follow-up.

Recent advances in myocarditis care and the absence of a dedicated guideline prompted the creation of this document, which was published in the Journal of the American College of Cardiology.

The document introduces a novel four-stage classification system for myocarditis:

• Stage A: At risk (patients with or exposed to risk factors).
• Stage B: Asymptomatic with evidence of myocardial inflammation.
• Stage C: Symptomatic myocarditis.
• Stage D: Advanced myocarditis with hemodynamic or electrical instability requiring intervention.

The classification is modeled after frameworks used in conditions like chronic heart failure and valvular heart disease, emphasizing that myocarditis is a dynamic condition with distinct trajectories.

This system aims to support research into the progression of myocarditis and therapies tailored to each stage.

The document seeks to increase awareness of myocarditis among clinicians across specialties, not just cardiologists.

A Five-Step Pathway for Management

1. Recognition of the three classic presentations: chest pain, heart failure/cardiogenic shock, and symptoms related to arrhythmias.
2. Triage to determine whether hospitalization, advanced heart failure care, or emergent management is needed.
3. Conducting pivotal diagnostic tests, including cardiac magnetic resonance (CMR) imaging and endomyocardial biopsy.
4. Administering appropriate treatment based on test results.
5. Providing longitudinal follow-up, which includes biomarker testing, imaging, genetic counseling/testing, and assessing fitness for physical activity.

The pathway stresses a low threshold for transferring high-risk patients to advanced centers, especially those with severe ventricular dysfunction or hemodynamic instability.

Follow-up includes imaging studies to track resolution, with repeat echocardiograms at 2-4 weeks and either a CMR or another echocardiogram at 6 months.

Genetic counseling and testing are recommended for all consenting individuals, recognizing the role of genetics in myocarditis development.

Addressing Knowledge Gaps

The document identifies knowledge gaps in the understanding of myocarditis trajectories and the impact of social determinants of health.

International registries are deemed essential to gather large-scale data and establish unified diagnostic standards.

Randomized controlled trials are encouraged to build a stronger evidence base for treatment.

This pathway is designed to be a practical guide for clinicians and was endorsed by key organizations, including the Heart Failure Society of America and the Myocarditis Foundation.

Take-Home Points

• A new ACC expert consensus pathway offers guidance on diagnosing and managing myocarditis.
• The four-stage classification system provides a framework for understanding disease progression.
• A five-step pathway emphasizes early recognition, triage, testing, treatment, and follow-up.
• Long-term follow-up and genetic testing are critical components of care.
• Collaboration through international registries and clinical trials will advance myocarditis research.

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