Long-term effects on cardiac function and symptoms in patients with myocarditis following COVID-19 vaccination: the ECHOVID-19 Long-term Study.

BACKGROUND

The long-term effects of myocarditis following COVID-19 vaccination on cardiac function and symptoms remain unclear.

PURPOSE: To assess the long-term effects of myocarditis following COVID-19 vaccination on cardiac function, inflammatory biomarkers and symptoms.

METHODS

Patients with myocarditis within 50 days of receiving COVID-19 vaccination (2021-2022) were invited to follow-up approximately 2 years after initial hospitalisation. Follow-up assessment included echocardiography, biomarkers, ECG, lung ultrasound (LUS) and symptom questionnaires. Patients with myocarditis following COVID-19 vaccination (V-myocarditis) were compared with non-vaccine-related myocarditis (NV-myocarditis) controls admitted during the same period.

RESULTS

17 patients with V-myocarditis (median age 47 (27-59) years, 53% women) were included. Median time from vaccination to admission was 6 days, with 88% admitted within 30 days. At follow-up (28±6 months), patients with V-myocarditis showed mildly impaired left ventricular (LV) function (median global longitudinal strain (GLS) 16.0% (13.2%-18.2%)) and diastolic dysfunction in 71%. Right ventricular (RV) and LUS findings were preserved. Biomarkers normalised from admission to follow-up with significant reductions in troponin-I (p<0.001) and C-reactive protein (p=0.001), while 35% showed persistent low-grade inflammation. Symptoms were common at follow-up, including fatigue (35%) and chest pain (41%). Compared with NV-myocarditis, patients with V-myocarditis had similar symptoms and biomarker recovery, but lower GLS at follow-up (NV-myocarditis: 18.5% (15.4%-20.3%), p=0.04).

CONCLUSION

In one of the longest reported follow-up studies of myocarditis following COVID-19 vaccination, patients exhibited mild LV and diastolic dysfunction, preserved RV function and overall normalised biomarkers. A notable proportion continued reporting symptoms, highlighting the need for long-term follow-up.