2D Speckle Tracking Strain Echocardiography in Multisystem Inflammatory Syndrome in Children: A Multicenter Analysis From the MUSIC Study

BACKGROUND: 2D-speckle tracking echocardiography may help detect subclinical ventricular dysfunction, but data in multisystem inflammatory syndrome in children (MIS-C) are scarce. We investigated left ventricular (LV) strain parameters in MIS-C and their association with outcomes. METHODS: We performed an ambi-directional, 32-center cohort study on hospitalized patients with MIS-C (March 2020–November 2021) with at least 1 echocardiogram read by the Core Lab. Generalized estimating equation modeling was used to test associations between LV strain and a composite in-hospital adverse cardiovascular outcome (vasoactive support, arrhythmias, cardiac arrest, extracorporeal support, death, or heart transplant). RESULTS: Of 349 patients (median age, 8.7 years [interquartile range, 5.3–12.9]), 35% had decreased LV ejection fraction during hospitalization, and 45% had depressed LV strain (either 4-chamber LV longitudinal strain [4CH-LVLS] or mid-ventricular LV circumferential strain [mid-LVCS]). The worst 4CH-LVLS and mid-LVCS occurred at ≈5 days of illness; 50% of abnormal LV strain normalized within 1 week, and 95% within 50 days. In-hospital adverse outcomes occurred in 35% of patients; these patients were older ( P =0.003) and, at admission, had more likely abnormal troponin ( P <0.001) higher C-reactive protein ( P <0.001), higher indexed LV end-diastolic volume ( P <0.001) and mass ( P =0.015), worse LV ejection fraction ( P <0.001), and worse LV strain (4CH-LVLS, P =0.002; mid-LVCS, P =0.001). Covariate-adjusted individual models for each strain parameter showed that 4CH-LVLS (adjusted odds ratio, 1.09 [95% CI, 1.07–1.12]), mid-LVCS (adjusted odds ratio, 1.06 [95% CI, 1.04–1.09]), worst LV strain Z score between 4CH-LVLS and mid-LVCS (adjusted odds ratio, 1.30 [95% CI, 1.21–1.41]), and early diastolic longitudinal strain rate (adjusted odds ratio, 1.68 [95% CI, 1.26–2.23]) at admission were found to be associated with adverse outcomes. CONCLUSIONS: About half of patients with MIS-C had abnormal LV strain during hospitalization. 4CH-LVLS, mid-LVCS, the most abnormal strain Z score, and early diastolic longitudinal strain rate at admission were independently associated with in-hospital adverse cardiovascular outcome. These data may help early characterization and prognostication in MIS-C.