SARS-CoV-2 Myocarditis Diagnostic Probability (Troponin + MRI + ECG)

ECG Pattern -- choose -- Normal Nonspecific repolarization changes Typical for myocarditis (diffuse ST-T changes / PR depression / new AV block / ventricular arrhythmia) CMR (2018 Lake Louise Criteria) -- choose -- Positive Equivocal / indeterminate Negative Not performed Days from Symptom Onset to CMR (leave blank if CMR not done) SARS-CoV-2 Myocarditis: Explanation and Clinical Context In patients with COVID-19, myocardial injury is common and manifests as troponin elevation with variable ECG changes. ECG alone has low specificity for myocarditis, whereas cardiac magnetic resonance (CMR) using the 2018 Lake Louise Criteria provides high diagnostic accuracy by combining T2-based edema markers with T1/ECV/LGE evidence of inflammatory injury. Early timing matters: performing CMR within 1–2 weeks of symptom onset maximizes sensitivity, and when paired with markedly elevated troponin, diagnostic pick-up is very high.

Troponin should be interpreted as a marker of injury rather than etiology; elevations >10× URL in the right clinical context strengthen probability but cannot, by themselves, establish myocarditis. This tool pragmatically synthesizes these elements to stratify probability into low, intermediate, high, and very high bands. It complements—not replaces—clinical judgment, guideline algorithms, and, when indicated, invasive testing.