P828 Echocardiographic two-dimensional speckle tracking identifies acute myocardial edema and sub-acute fibrosis in pediatric focal myocarditis with normal ejection fraction: comparison with MRI

Abstract Aim To evaluate the ability of Speckle Tracking Echocardiography (STE), as compared to Cardiac Magnetic Resonance (CMR), in identifying acute and sub-acute abnormalities in systolic function occurring with focal myocarditis in children and adolescents without evident wall motion abnormalities. Methods: We analyzed data from 33 consecutive patients (age 4-17year) with CMR-confirmed focal myocarditis and without regional motion abnormalities and/or reduced ejection fraction. Patients underwent echocardiography with analysis of regional and global longitudinal strain and CMR for the identification of focal edema and myocardial fibrosis. Impaired longitudinal strain was defined according to previously reported age-specific reference values. Results: Despite normal ejection fraction at admission, prevalence of impaired systolic function by STE was present in 58% of patients (n = 19). Reduction in longitudinal strain was regionally related to CMR-identified edema areas, with lowest values found at the level of the infero-lateral segments as compared to the mean of the other segments (p < 0.05). Amount of CMR-edema was strongly correlated with impairment of STE (r=-712; p = 0.01). At follow-up, significant improvement in global longitudinal strain could be observed in all patients (p < 0.001) with STE normalization recorded in 13 of 19 patients. Persistent regional impairement in STE could however still be found 6 patients, consistent with residual focal cardiac fibrosis at follow-up CMR. Conclusion: In children and adolescents with focal myocarditis, STE identifies subclinical abnormalities in systolic function, consistent with regional edema at CMR. In addition, analysis of STE provides insights in the identification of regional recovery or persistent systolic impairment, possibly due to residual focal fibrosis. Abstract P828 Figure.