Abstract 13796: Diffuse Regional Strain Abnormalities Despite Normal Ejection Fraction Suggestive of Occult Myocardial Dysfunction in Multisystem Inflammatory Syndrome in Children

Abstract

Background: Multisystem Inflammatory Syndrome in Children (MIS-C) patients frequently present with significant hypotension and ventricular dysfunction. While they appear to recover quickly after treatment of MIS-C, long-term sequelae of the myocardium are unknown. We aimed to evaluate ventricular function longitudinally using TTE and CMR. Methods: Retrospective review was performed of all patients with MIS-C who underwent CMR from September 2020 to May 2021. Measures of ventricular size and function during admission, 2-week, and 6-week follow up by TTE as well as global and regional longitudinal strain, as measured by Strain ENCoded imaging (SENC) by CMR were analyzed. The magnitude of strain is expressed as an absolute value, with >17% considered normal. Results: Nineteen patients (13.9±1.9 years, 63% males) with MIS-C underwent CMR. Troponin leak was seen in 16/19 (84%), 15/19 (79%) had ventricular dysfunction, 3/19 (16%) had coronary abnormality, and 1/19 (5%) required ECMO. All patients had normalized function at 2- and 6-week visits (mean LVEF 62±6.3% on TTE at 6-weeks). Group 1 (n=2) had CMR during hospital admission (5, 11 days), Group 2 (n=13) during early outpatient follow-up (median 34 days, range 15-59 days), and Group 3 (n=5) during later outpatient follow-up (median 98 days, range 72-231 days). All patients had normal LVEF on CMR. LVGLS by SENC was significantly impaired throughout follow up. The mean LVGLS of Group 1, Group 2, and Group 3 were 15±0.8%, 15.4±2.4%, and 16.6±1.6%, respectively. The mean number LV segments (from the AHA modified 16 segment model) with abnormal LS in each group were 10±2, 9.2±3.2, and 8.6±2, respectively. Conclusions: There were significant global and regional strain abnormalities despite normalized LVEF on TTE and CMR. This represents occult myocardial dysfunction after MIS-C. It is unclear if these findings will persist. Longitudinal studies are needed to monitor for progression or resolution of these findings.