Detailed Assessment of Left Ventricular Function in Multisystem Inflammatory Syndrome in Children, Using Strain Analysis.

Background: Cardiac manifestations in multisystem inflammatory syndrome in children (MIS-C) occur in ∼80% of patients. Left ventricular (LV) systolic dysfunction is the most frequent cardiac finding.

Methods: In this single-centre, retrospective cohort study, we report on detailed assessment of LV function in MIS-C patients using strain and strain rate analysis. We compare those with normal peak systolic strain z-scores (both longitudinal and circumferential strain) to those with abnormal peak systolic strain z-scores (decreased circumferential and/or longitudinal strain).

Results: Among 25 patients, 14 (56%) were male, 20 (80%) were Black or Hispanic, 13 (52%) were overweight/obese, and the median age was 11.4 years (interquartile range: 7.5 to 16). Median ejection fraction (EF) was 55.2% (interquartile range: 48.3% to 58%), with the abnormal strain patients having a lower EF (P < 0.01). Demographics were similar between groups. The abnormal strain patients had more organ systems involved and were more likely to require inotropic support. In a comparison of MIS-C patients with normal EF (n = 15) to controls, MIS-C patients had lower peak systolic strain as well as lower early diastolic strain rates. In patients with initially depressed function, EF normalized in 8 of 10 (80%), but 4 of 11 (36%) patients had persistently abnormal systolic strain after discharge.

Conclusions: LV systolic dysfunction is common in the acute phase of MIS-C, and detection may be improved with strain imaging. Longitudinal cardiac follow-up is imperative, as some patients may be at risk for persistent LV dysfunction.