Clinical presentation of myocarditis and its association with cardiac imaging features and clinical outcome
L Lorenzo Alves, J Goncalves, T Branco, B Viana, E Andrade, S Amorim, R Rdorigues, M VasconcelosAbstract
Background
Myocarditis presents with heterogeneous clinical phenotypes, ranging from chest pain–dominant presentations to heart failure, arrhythmic or haemodynamically unstable forms. Whether the initial clinical presentation reflects differences in myocardial imaging characteristics and clinical trajectory remains incompletely defined.
Purpose
To investigate whether the initial clinical presentation of myocarditis is associated with differences in cardiac magnetic resonance (CMR) findings and clinical outcomes.
Methods
We conducted a retrospective observational study including consecutive patients admitted with myocarditis to a tertiary referral centre between January 2016 and November 2025. Patients were categorised according to initial presentation as chest pain or non–chest pain (heart failure, syncope or arrhythmia). Baseline assessment included clinical variables, biomarkers, electrocardiography, echocardiography and CMR. CMR evaluation comprised ventricular volumes and function, myocardial oedema, late gadolinium enhancement (LGE) extent and pattern, native T1/T2 values, and Lake Louise criteria. Acute management variables and clinical outcomes, including cardiovascular rehospitalisation, ventricular function during follow-up and mortality, were recorded.
Results
Among 138 patients, 128 (92.8%) presented with chest pain and 10 (7.2%) with a non–chest pain phenotype. Patients without chest pain were older (p=0.002) and had a more severe acute clinical profile, with higher natriuretic peptide levels (p<0.001), greater need for ventilatory and inotropic support (both p<0.001), mechanical circulatory support (p=0.001), and longer hospitalisation (p<0.001). On acute CMR, the prevalence of myocardial oedema, LGE, and Lake Louise criteria positivity did not differ between groups. However, non–chest pain presentation was associated with lower CMR-derived LVEF (p<0.001) and a higher prevalence of intramyocardial LGE pattern (p=0.020). During follow-up, non–chest pain presentation was associated with more cardiovascular rehospitalisations and higher device implantation rates. In multivariable analysis, non–chest pain presentation independently predicted reduced CMR LVEF (OR 52.8, 95% CI 4.25–656.0; p=0.002).
Conclusion
Initial clinical presentation in myocarditis provides meaningful prognostic information beyond inflammatory CMR findings. While markers of myocardial inflammation are comparable across presentations, a non–chest pain phenotype is strongly associated with early functional impairment, haemodynamic compromise and a more adverse clinical course, supporting its role as a simple tool for early risk stratification.Table. OutcomesFor image description, please refer to the figure legend and surrounding text.BoxplotFor image description, please refer to the figure legend and surrounding text.