Improved diagnosis of COVID-19 vaccine-associated myocarditis with cardiac scarring identified by cardiac magnetic resonance imaging

Abstract

AbstractBackgroundMyocarditis is a rare but potentially serious complication of COVID-19 vaccination. Cardiac magnetic resonance (CMR) late gadolinium enhancement (LGE) imaging can identify cardiac scar, which may improve diagnostic accuracy and prognostication.ObjectivesTo define the incidence of long-term LGE post COVID-19 vaccine-associated myocarditis (C-VAM) and to establish the additive role of CMR in the diagnostic work-up.MethodsPatients with Brighton Collaboration Criteria Level 1 (definite) or Level 2 (probable) C-VAM were prospectively recruited from the Surveillance of Adverse Events Following Vaccination In the Community (SAEFVIC) database to undergo CMR at least 12 months after diagnosis. As there were limited patients with access to baseline CMR, prior CMR results were not included in the initial case definition. The presence of LGE on follow-up CMR was then integrated into the diagnostic algorithm and the reclassification rate (definite vs. probable) was calculated.ResultsSixty-seven patients with C-VAM (mean age 30 ± 13 years, 72% male) underwent CMR evaluation. Median time from vaccination to CMR was 548 (range 398-603) days. Twenty patients (30%) had persistent LGE, most frequently found in the basal inferolateral segment (n = 11). At diagnosis, nine patients (13%) were classified as definite and 58 (87%) as probable myocarditis. With integration of CMR LGE data, 16 patients (28%) were reclassified from probable to definite myocarditis.ConclusionPersistent LGE on CMR occurs in one third of patients with C-VAM. Without CMR at diagnosis, almost one third of patients are misclassified as probable rather than definite myocarditis.