Conventional MRI findings continue to outperform newer mapping measures for predicting long-term risk in acute myocarditis. The study, published in the International Journal of Cardiology, found that patients meeting the original LL criteria had significantly higher cardiac event rates than those diagnosed using mapping-based methods, reaffirming the strong prognostic value of traditional imaging markers.

The study included 210 adults with hemodynamically stable acute myocarditis diagnosed according to updated LL criteria. Participants were divided into two groups. The first group, defined by the original LL criteria, had both myocardial edema on T2-STIR imaging and non-ischemic LGE. The second group met diagnosis through mapping-based parameters, including T1, T2, or extracellular volume (ECV) mapping.

Over a median follow-up of 57 months, 31 cardiac events were recorded, including cardiac death, heart failure hospitalization, myocarditis recurrence, or appropriate implantable cardioverter-defibrillator shocks. All 31 events occurred in patients fulfilling the original LL criteria, while none occurred among those diagnosed by mapping measures alone.

Kaplan-Meier analysis demonstrated that patients meeting the original criteria had a significantly worse prognosis (p < 0.0001). A greater number of fulfilled LL criteria also correlated with poorer outcomes (p = 0.0002). On multivariate analysis, both the number of LL criteria and the presence of midwall-septal or ring-like LGE patterns remained independent predictors of major cardiac events (p < 0.0001).

These findings confirm that the combination of myocardial edema and LGE provides robust prognostic information in stable myocarditis. Mapping criteria alone offered limited predictive value and should complement, rather than replace, conventional LL imaging in clinical risk assessment.