Endomyocardial Biopsy Yield Predictor (Myocarditis Suspicion Model)

Endomyocardial Biopsy Yield Predictor (Myocarditis Suspicion Model): Explanation and Clinical Context This calculator estimates the probability that an endomyocardial biopsy (EMB) will provide a specific histopathologic or immunohistochemical diagnosis in patients with clinically suspected myocarditis. Diagnostic yield in contemporary cohorts averages around 50–55%, depending on timing, imaging, sampling site, and targeting method. Clinical interpretation Early biopsy (≤14 days), positive cardiac MRI (updated Lake Louise Criteria), LV or biventricular sampling, electroanatomic mapping, and obtaining ≥5–7 specimens all substantially improve yield.

Delayed biopsy (>30 days) or right-ventricular-only sampling tends to reduce diagnostic return. The model assumes a baseline yield of 53% and applies incremental effects derived from published observational data. Use in practice Predicted yield <30% → low likelihood; optimize strategy before proceeding.

30–60% → intermediate yield; typical for most myocarditis biopsies. >60% → high yield; strategy optimized (early, LV/biventricular, mapping, adequate samples).