Table 2.
Clinical characteristics and results of EMB of patients with clinically suspected acute myocarditis following mRNA COVID‐19 vaccination (n = 24)
| ID | EMB localization | Sex | Age | EF (%) | Cardiac histology | Viral PCR | Cardiac MRI |
|---|---|---|---|---|---|---|---|
| Acute myocarditis | |||||||
| #1 (case 1) | LV | M | 18 | 33 | Acute lymphocytic myocarditis | Negative | Patchy intramural LGE |
| #2 | RV | M | 35 | 42 | Acute lymphocytic myocarditis | EBV | Inferolateral LGE |
| #3 (case 3) | LV | M | 38 | 48 | Acute lymphocytic myocarditis | Negative | Patchy intramural LGE |
| #4 | LV | M | 28 | 48 | Acute eosinophilic endomyocarditis (Löffler endomyocardits) | Negative | n/a |
| #5 | LV | M | 40 | 43 | Acute focal lymphocytic myocarditis | Negative | n/a |
| Chronic myocarditis | |||||||
| #6 | LV | M | 20 | 60 | Mild healing/chronic lmphocytic myocarditis | Negative | Apical lateral LGE |
| #7 | LV | M | 68 | 30 | Mild healing/chronic lmphocytic myocarditis | Negative | Diffuse focal LGE |
| #8 | LV | M | 19 | n/a | Mild healing/chronic lmphocytic myocarditis | Negative | n/a |
| #9 | RV | M | 17 | 50 | Mild healing/chronic lmphocytic myocarditis | PVB19 (377 copies/μg DNA) | Planned after EMB |
| #10 | RV | M | 16 | 65 | Mild healing/chronic lmphocytic myocarditis | Negative | Planned after EMB |
| #11 | LV | M | 20 | 40 | Mild healing/chronic lmphocytic myocarditis | Negative | LV free wall LGE |
| Cardiac sarcoidosis | |||||||
| #12 | LV | M | 26 | 49 | Focal granulomatous inflammation with non‐necrotizing epithelioid cells granulomas with multi‐nucleated giant cells | Negative | n/a |
| Healed myocarditis | |||||||
| #13 (case 2) | LV | M | 22 | 40 | Healed myocarditis | HHV6B | Patchy intramural and pericardial LGE |
| #14 | LV | M | 16 | 75 | Healed myocarditis | Negative | Inferior LGE |
| #15 | RV | F | 45 | n/a | Healed myocarditis | Negative | Subepicardial midventricular LGE |
| #16 | RV | M | 21 | 60 | Healed myocarditis | PVB19 (678 copies//μg DNA) | Lateral basal and apical subepicardial LGE |
| #17 | RV | n/a | 36 | 35–40 | Healed myocarditis | HHV6B | n/a |
| #18 | LV | M | 32 | 60 | Healed myocarditis | HHV6B | n/a |
| Other diagnoses (cardiac damage with unclear aetiology) | |||||||
| #19 | LV | M | 39 | 20 | Chronic myocardial damage with moderate perivascular accentuated fibrosis and microangiopathy | Negative | n/a |
| #20 | LV | M | 33 | 65 | Chronic myocardial damage with interstitial fibrosis | Negative | lateral LGE |
| #21 | LV | M | 35 | 60 | Mild chronic myocardial damage | Negative | n/a |
| #22 | RV | M | 38 | 15 | Chronic myocardial damage with interstitial fibrosis | Negative | n/a |
| #23 | LV | M | 43 | 48 | Moderate chronic myocardial damage | Negative | n/a |
| #24 | RV | M | 17 | 50 | Mild chronic myocardial damage | Negative | focal LGE |
EMB revealed acute myocarditis in 5 (20.8%), chronic myocarditis in 6 (25%), cardiac sarcoidosis in 1 (4.2%), healed myocarditis in 6 (25%) and other diagnoses with cardiac damage of unclear aetiology in 6 (25%) patients.
EBV, Epstein–Barr‐Virus; EMB, endomyocardial biopsy; EF, ejection fraction; HHV6B, human herpes virus 6B; LV, left ventricle; M, male; n/a, not available; MRI, magnetic resonance imaging; PCR, polymerase chain reaction; PVB19, parvovirus B19; RV, right ventricle; W, female.