Abstract 14254: Myocarditis in Athletes and Non-Athletes: Evaluating the Persistence and Degree of Myocardial Fibrosis at Follow Up

Abstract

Introduction: Myocarditis is a common acquired cardiac disorder that may lead to persistent scar. Current guidelines recommend follow up cardiac MRI (CMR) in 3-6 months for athletes. Data supporting this recommendation is unfortunately very limited. Aim: The aim of this study was to evaluate the demographic and clinical variables of patients diagnosed with myocarditis. Clinical data for those who had a follow up CMR was also evaluated separately. Methodology: Patients who had a cardiac MRI (CMR) organised between July 2019 till December 2022 because of a MINOCA/Myocarditis hospital admission were retrospectively reviewed. Those with a myocarditis diagnosis were included. An athlete was defined as an individual who engaged in >4 hours of physical activity weekly or underwent organized sport. Results: 105 patients were included (mean age 35.4±15.6 years, 83.8% male). 34.3% were athletes. 12.4% had possible acute myocarditis, 10.5% had likely myocarditis and 77.1% had confirmed myocarditis on cardiac MRI (median 4 days from presentation). ECG was abnormal in 60.0%. 8.6% had arrhythmias. Echocardiography was abnormal in 26.7%. CMR revealed 15.2% reduced LV EF, 57.1% regional wall motion abnormalities, 5.7% reduced RV EF, 25.7% pericardial effusion, 84.5% myocardial oedema. Most (88.5%) had late gadolinium enhancement (LGE). 56.2% were started on anti-heart failure medical therapy. 29.5% had a CMR repeated (interval between scans 14.7±14.2 months). 77.4% showed persistent LGE, less pronounced in most (71.0%). Diffuse LGE at baseline was the only predictor for persistent scar (p=0.004). Scar persisted equally in athletes and non-athletes (p=0.666). Clinical variables were similar in both. At follow-up (24.6±15.3 months), 8.6% had adverse outcomes. The event rate was similar in athletes and non-athletes. A low LV EF on CMR (p=0.011) and abnormal ECHO (p=0.027) were the only variables that could predict outcome. Conclusion: LGE after myocarditis persists in 77.4% of cases, albeit better. No variable could predict the persistence of LGE in this cohort. Athletes and non-athletes had a similar clinical course, suggesting that repeat CMR in non-athletes is reasonable. The diagnostic utility of repeat CMR after myocarditis remains questionable.