Cardiac Manifestations and Persistent Myocardial Dysfunction in Multisystem Inflammatory Syndrome in Children: Insights from Conventional and Strain Echocardiography

TL;DR

This study shows that MIS-C often causes heart problems in children, and strain echocardiography reveals hidden heart damage even when traditional tests look normal.

Contribution

The study demonstrates that strain imaging detects persistent myocardial dysfunction in MIS-C patients, even when ejection fraction appears normal.

Findings

LV global longitudinal strain was significantly reduced in MIS-C patients compared to controls at both the day of worst dysfunction and discharge.

Strain abnormalities persisted even after left ventricular ejection fraction recovered to normal levels.

LV global longitudinal strain and apical infero-septal strain were the strongest predictors of reduced left ventricular ejection fraction.

Abstract

Background: Multisystem inflammatory syndrome in children (MIS-C) is a severe post-infectious complication of SARS-CoV-2, often with cardiac involvement. Myocardial strain imaging may detect dysfunction missed by conventional echocardiography. The objectives of this study are to characterize cardiac manifestations of MIS-C and assess the value of strain imaging in children with preserved and reduced left ventricular ejection fraction (LV-EF). Methods: We retrospectively analyzed 22 MIS-C patients admitted between September 2020 and January 2024, all with cardiac involvement. Clinical, laboratory, and echocardiographic data—including 2D and speckle-tracking strain—were collected at the day of worst dysfunction (DWD) and discharge (DD) and compared with 22 matched controls. Results: Median age was 4.65 years; 59% male; 45% overweight/obese. LV systolic dysfunction (LV-EF < 50%) occurred in 54.5%, coronary abnormalities in 36.4%, and pericardial effusion in 95.5%. LV global longitudinal strain (LVGLS) was significantly lower than controls at the DWD (−15.45 ± 4.76%, p < 0.0001) and DD (−20.63 ± 4.66%, p = 0.014). Strain abnormalities persisted despite LV-EF recovery, and even patients with preserved LV-EF showed significant segmental strain reduction. LVGLS and apical infero-septal strain were strongest predictors of reduced LV-EF. Conclusions: MIS-C often causes systolic dysfunction and coronary changes, but strain imaging reveals persistent subclinical myocardial injury. Long-term cardiac monitoring is warranted.

Figures