CMR Findings in the Long-Term Outcomes After Multisystem Inflammatory Syndrome in Children (MUSIC) Study

Area of Science:

• Pediatric Cardiology
• Cardiovascular Imaging
• Pediatric Infectious Diseases

Background:

• Multisystem Inflammatory Syndrome in Children (MIS-C) often involves acute cardiac complications.
• Long-term effects of MIS-C on cardiac function are not well understood.
• Cardiac magnetic resonance (CMR) can assess myocardial health in MIS-C.

Purpose of the Study:

• To characterize systolic function and myocardial tissue properties in MIS-C patients.
• To evaluate medium-term cardiac sequelae in a large cohort of MIS-C patients.
• To utilize CMR imaging for detailed cardiac assessment post-MIS-C.

Main Methods:

• Analysis of 263 CMR studies from 255 MIS-C patients across 32 North American centers.
• Assessment of ventricular volumes, tissue characterization, and coronary arteries by a core laboratory.
• Longitudinal evaluation at 3 months, 6 months, and 1 year post-hospitalization.

Main Results:

• Left ventricular dysfunction was mild and infrequent (6.7% initially, decreasing over time).
• Late gadolinium enhancement (myocardial scarring) was rare (0.8%).
• Coronary artery dilation occurred in 7.5% of patients; 3.5% met criteria for myocarditis.

Conclusions:

• Medium-term follow-up reveals a low prevalence of significant cardiac dysfunction and myocardial abnormalities in MIS-C patients.
• Mild residual cardiac abnormalities can persist in a small subset of patients up to 1 year post-hospitalization.
• CMR is valuable for assessing cardiac recovery and identifying potential long-term sequelae in MIS-C survivors.