ESC 2025 Myocarditis risk stratification and its association with cardiac magnetic resonance findings and clinical outcomes at follow-up
L Lorenzo Alves, J Goncalves, B Viana, E Andrade, T Branco, R Rodrigues, M VasconcelosAbstract
Background
The 2025 ESC Guidelines for myocarditis and pericarditis introduced a novel risk stratification framework for acute myocarditis, primarily aimed at identifying patients at risk of early complications. Whether this classification is also associated with longer-term myocardial recovery assessed by cardiac magnetic resonance (CMR) remains insufficiently explored in real-world populations.
Purpose
To assess the association between ESC 2025 myocarditis risk categories and structural and functional abnormalities on follow-up CMR, and their relationship with clinical events.
Methods
We conducted a retrospective observational study including consecutive patients admitted with acute myocarditis to a tertiary referral centre between January 2016 and November 2025. Patients were classified into low, intermediate, and high-risk categories according to the ESC 2025 risk stratification. Follow-up CMR outcomes included persistent late gadolinium enhancement (LGE), extensive LGE (≥4 segments), myocardial oedema, and persistent left ventricular systolic dysfunction (LVEF <50%). Clinical outcomes included all-cause mortality, malignant ventricular arrhythmias, cardiovascular hospitalisations, implantable cardioverter-defibrillator implantation, and heart transplantation.
Results
Among 138 patients (81% male, median age 28 years [IQR 22–38]), follow-up CMR was available in 48 (35%). Persistent LGE was common across all ESC risk categories (low 50%, intermediate 80.6%, high 75%; p=0.38), without discrimination between intermediate and high-risk groups. In contrast, persistent extensive LGE (≥4 segments) showed a strong stepwise association with ESC risk (0% low, 27.6% intermediate, 83.3% high; p=0.026; p for trend=0.009). Each incremental increase in ESC risk category was independently associated with extensive LGE persistence (OR 13.7, 95% CI 1.4–132.1; p=0.024). The number of LGE-positive myocardial segments increased across ESC risk strata (p=0.018). Persistent left ventricular dysfunction also increased across risk categories (0%, 2.8%, and 28.6%; p for trend=0.025). Non-subepicardial LGE patterns were associated with higher ESC risk and independently predicted clinical events (OR 12.0, 95% CI 1.9–75.1; p=0.008). Major clinical events were infrequent and did not differ significantly across risk categories.
Conclusion
The ESC 2025 myocarditis risk stratification identifies a clear gradient of persistent myocardial injury and impaired recovery on follow-up CMR, particularly related to extensive and non-subepicardial LGE. While clinical events were uncommon, CMR endpoints provided superior discrimination of longer-term risk, supporting the complementary prognostic value of follow-up CMR beyond the acute phase.Distribution of persistent LGEFor image description, please refer to the figure legend and surrounding text.Number of myocardial segments with LGEFor image description, please refer to the figure legend and surrounding text.