The Evolving Phenotype of Myocarditis: The Role of Cardiovascular Magnetic Resonance from Acute Injury to Healing and Residual Scar

Myocarditis is a dynamic disease, and myocardial oedema, injury, ventricular dysfunction, and fibrosis may evolve differently over time. Cardiovascular magnetic resonance (CMR) has become central to its non-invasive assessment, providing complementary information on myocardial tissue through T2-sensitive imaging, native T1, extracellular volume (ECV), and late gadolinium enhancement (LGE). The meaning of these findings, however, depends on when imaging is performed. Follow-up CMR may therefore provide a better understanding of myocardial recovery, helping to characterize resolving myocardial injury, persistent tissue abnormalities, and residual post-acute changes. Based on the temporal evolution of CMR findings, we propose four conceptual patterns of myocardial recovery: near-complete imaging recovery; resolving oedema/injury-pattern abnormalities; persistent oedema/injury-pattern abnormalities; post-acute injury with residual LGE and potential structural remodelling. These patterns are intended as a framework for interpreting serial CMR rather than as formally validated imaging phenotypes, and should be considered complementary to contemporary clinical disease-stage and mechanistic classifications. In selected patients, integration with echocardiography, molecular imaging, genetics, and endomyocardial biopsy may provide further insight into the underlying disease process. Whether this longitudinal approach can improve risk stratification and ultimately guide therapeutic decisions remains an important question for future studies.