Post-infectious Autoimmune Cardiac Risk Index (Autoantibodies Panel)

Post-infectious Autoimmune Cardiac Risk Index (Autoantibodies Panel): Explanation and Clinical Context Post-infectious autoimmune cardiac disorders represent a spectrum of myocardial and endocardial injury that follows infectious triggers such as viral myocarditis, bacterial infections, or systemic inflammatory responses. The immune system, after pathogen clearance, may continue to recognize cardiac antigens as foreign due to molecular mimicry between microbial epitopes and myocardial proteins. This Autoimmune Cardiac Risk Index integrates six well-established autoantibody markers—anti-myosin, anti-troponin I, β1-adrenergic receptor, M2-muscarinic receptor, anti-myosin heavy chain, and anti-endothelial cell antibodies—to provide a semi-quantitative assessment of post-infectious autoimmune cardiac activity.

Interpretation: A higher composite index reflects a stronger autoimmune signature, suggestive of ongoing or evolving myocardial inflammation. In patients with elevated cardiac enzymes, arrhythmias, or left ventricular dysfunction post-infection, this index supports the consideration of autoimmune myocarditis, virus-negative inflammatory cardiomyopathy, or post-COVID immune-mediated cardiac syndromes. Clinical Application: - Early identification of autoimmune myocarditis and potential progression to dilated cardiomyopathy. - Guidance for immunomodulatory or immunosuppressive therapy initiation. - Monitoring therapeutic response during follow-up, particularly in virus-negative myocarditis.

Limitations: This index is a research-based composite model. Variations in antibody quantification methods and threshold standardization across laboratories can affect its predictive accuracy. Clinical correlation with imaging (CMR, PET) and endomyocardial biopsy findings remains essential.