Speckle-tracking and conventional echocardiography in MIS-C: tracking cardiac involvement and recovery.

Abstract

Background: Multisystem inflammatory syndrome in children (MIS-C), a complication of COVID-19, is frequently associated with cardiac involvement. Although most affected children recover, the extent and duration of myocardial abnormalities remain uncertain. This study evaluates mid-term cardiac function in MIS-C patients, with and without cardiac involvement, using transthoracic echocardiography (TTE) and speckle-tracking echocardiography (STE).

Methods: This case-control study (2022-2023) included 90 children: 30 with MIS-C and cardiac involvement, 30 with MIS-C without cardiac involvement, and 30 healthy controls. TTE and STE were used to assess left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) at diagnosis and at three months, comparing outcomes across groups.

Results: The cardiac involvement group exhibited significantly elevated ferritin and C-reactive protein levels (P = 0.006 and P = 0.017, respectively) and a higher prevalence of troponin positivity (56.67% vs. 20%, P = 0.009). At baseline, these patients had markedly reduced LVEF (56.5 ± 4.3) and GLS (-21.6 ± 3.21) compared to healthy controls (LVEF: 68.2 ± 5.21; GLS: -24.8 ± 1.48; both P < 0.001). Notably, the basal segment showed significant longitudinal strain reduction (-18.75 ± 3.89 vs. -23.58 ± 0.27, P = 0.027), while differences in the apical and mid segments were not significant. By three months, LVEF (69 ± 4.21, P = 0.53) and GLS (-24.13 ± 2.39, P = 0.17) normalized. Heart failure and coronary artery brightness resolved in all affected patients, and most structural abnormalities improved; only two cases exhibited persistent mild left ventricular dilation. Regional strain analysis at follow-up revealed values comparable to those of healthy controls across all segments.

Conclusion: Cardiac dysfunction in MIS-C largely resolves within three months, with LVEF and GLS returning to normal. However, persistent myocardial abnormalities in a few cases highlight the need for long-term cardiac monitoring to detect and manage potential sequelae.