Evaluation of myocarditis in a pediatric population using cardiovascular magnetic resonance and endomyocardial biopsy.

OBJECTIVES

To evaluate myocarditis in a pediatric population using cardiovascular magnetic resonance (CMR) and endomyocardial biopsy.

METHODS

Twenty suspected for myocarditis patients aged 8-16 years and 20 controls were evaluated. CMR was performed using STIR T2-weighted (T2W), early T1-weighted (EGE) and late gadolinium-enhanced images (LGE). Immunohistologic and polymerase chain reaction (PCR) analysis of myocardial specimens were employed in 8/16, who fulfilled the criteria for myocarditis according to clinical and CMR findings.

RESULTS

Typical clinical, ECG and echocardiographic presentation were identified in 10/16. Troponine I was positive only in 3/16 patients. T2 and EGE in myocarditis were increased compared to controls (2.35 ± 0.5 vs. 1.57 ± 0.13, p<0.001 and 8.5 ± 3 vs. 3.59 ± 0.08, p<0.001, respectively). LGE was found only in 10/16 patients. Endomyocardial biopsy, performed in 8/16 patients with positive CMR, showed positive immunohistology in 2/8 and presence of viral genomes in 6/8 (Herpes, Parvo B19 and Epstein-Barr). Left ventricular ejection fraction (LVEF) was significantly decreased compared to controls (49.6 ± 14.8 vs. 64 ± 0.2, p<0.001). After 6 months, CMR showed normalization of T2, EGE and decreased/or absent LGE. LVEF was normal in all, except two, who remained with low LVEF but in a stable clinical condition.

CONCLUSIONS

In a small Greek pediatric population with myocarditis, CMR proved useful for the detection of myocarditis, especially in those with negative troponine and mild clinical presentation.