Myopericarditis versus myocarditis: the impact of concomitant pericarditis on cardiac magnetic resonance phenotype and clinical course
L Lorenzo Alves, J Goncalves, B Viana, T Branco, E Andrade, S Amorim, R Rodrigues, M VasconcelosAbstract
Background
Myopericarditis is a frequent presentation within the spectrum of myocardial inflammatory diseases, yet its association with acute severity, myocardial injury on cardiac magnetic resonance (CMR), and subsequent clinical evolution remains incompletely characterised.
Purpose
To evaluate the impact of concomitant pericarditis on clinical phenotype, CMR injury pattern, and functional and clinical evolution in patients with myocarditis.
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 classified according to the presence of concomitant pericarditis. Baseline assessment included clinical presentation, biomarkers, echocardiography, and CMR. Acute disease severity was assessed using objective clinical markers. Follow-up evaluation included CMR assessment of left ventricular ejection fraction (LVEF) and late gadolinium enhancement (LGE) persistence when available, as well as clinical outcomes.
Results
Among 138 patients, 82 (59.4%) had concomitant pericarditis. These patients were more frequently male (89.0% vs 69.6%, p=0.004) and presented almost exclusively with chest pain (100% vs 82.1%, p<0.001). Normal LVEF at presentation was more common in patients with pericarditis (87.8% vs 69.1%, p=0.007), while severely reduced LVEF occurred only in those without pericarditis. Markers of acute severity were numerically lower with pericarditis but did not reach statistical significance. Troponin levels were similar between groups, whereas BNP levels were significantly lower in patients with myopericarditis (38 vs 93 pg/mL, p=0.002). Acute CMR findings were comparable, including myocardial oedema, LGE prevalence, and Lake Louise criteria. On follow-up CMR, persistent LV systolic dysfunction occurred exclusively in patients without pericardial involvement (19.0% vs 0%, p=0.011), while persistent LGE was more frequent in patients with myopericarditis (83.9% vs 56.5%, p=0.027). Adverse clinical events were less frequent in patients with concomitant pericarditis (9.7% vs 33.3%, p=0.034), driven mainly by higher rates of cardiovascular rehospitalisation, persistent ventricular dysfunction, and device therapy in patients without pericarditis.
Conclusion
In myocarditis, concomitant pericarditis identifies a distinct clinical phenotype characterised by chest pain presentation, preserved ventricular function, and lower haemodynamic stress. Despite similar acute CMR inflammatory findings and more frequent LGE persistence, patients with myopericarditis experienced less persistent LV dysfunction and fewer adverse clinical events. These findings support myopericarditis as a prognostically distinct entity in which residual myocardial scar does not necessarily translate into adverse functional or clinical outcomes.Table clinical profileFor image description, please refer to the figure legend and surrounding text.Boxplot LVEFFor image description, please refer to the figure legend and surrounding text.