PURPOSE: We investigated iron status and inflammatory activation to predict myocardial damage in cardiac magnetic resonance (CMR) in patients with MCD.
METHODS: Consecutive patients hospitalized for MCD (the diagnosis was based on clinical symptoms, elevated myocardial necrosis biomarkers, and excluded coronary artery disease) in a tertiary referral cardiology center in 2017-2018 were enrolled and followed-up after 30 weeks (including CMR). Age- and sex-matched volunteers were considered a control group.
RESULTS: We compared clinical, laboratory and CMR data of 11 patients with MCD (age: 31 [26–34] years; men: 95%; baseline left ventricular ejection fraction [LVEF]; 56±10%) and 13 control subjects. Regarding CMR parameters, patients with MCD vs. controls had lower LVEF (57 (54–59) vs. 60 (58–63)%; p<0.05), longer native T1 [1053 (1038–1073) vs. 1018 (993–1029) ms; p<0.01] and higher T2 ratio [2,08 (1,69–2,5) vs. 1.59 (1,25–1,7); p<0.05]. Median number of left ventricle segments with oedema in MCD was 3 and with late gadolinium enhancement (LGE) – 6. Controls had neither oedema nor LGE segments.
In MCD patients we observed myocardial recovery after 30 weeks, defined as a decrease in the number of LV segments with oedema [from 3 (0–4) to 0 (0–0)] and with LGE [from 6 (4–7) to 4 (3–5)], native T1 [from 1053 (1038–1073) to 1030 (1010–1033) ms] and T2 ratio [from 2,1 (1,7–2,5) to 1,6 (1,5–1,7)] (all p<0.05). Importantly, clinical recovery was heterogenous – there was no recovery of LV segments with LGE in about 1/3 of followed-up patients.
There was a trend towards higher ferritin related to baseline T2 ratio (R= 0.5, p=0.1), and between the ferritin and baseline number of LV segments with oedema (R= 0.5, p=0.1). In patients with MCD serum ferritin correlated with the area of the major LGE focus after 30 weeks of follow-up (R=0.82, p<0.05). Neither troponin nor N-terminal pro-B type natriuretic peptide correlated with CMR indices of myocardial oedema or necrosis.
CONCLUSIONS: Our data report that clinical parameters which are on the crossroad of immune response and iron metabolism are related to pathophysiology of myocarditis. High circulating ferritin may predict myocardial oedema and fibrosis persisted after 30 weeks of follow-up in patients with MCD.