Clinical Predictors of Subacute Myocardial Dysfunction in Multisystem Inflammatory Syndrome in Children (MIS-C) Associated with COVID-19

Echocardiograms and bed placement in patients with multisystem inflammatory syndrome in children

Background

Understanding of multisystem inflammatory syndrome in children (MIS-C) continues to evolve with extensive evaluations, including echocardiograms, obtained in emergency departments (EDs) to assist with clinical decision making and bed allocation. We assessed the utility of obtaining echocardiograms in the ED to assist in determining bed placement for this patient population.

Methods

This 2-year retrospective single-center study of patients 0-21 years old without underlying cardiac disease hospitalized for MIS-C focused on individuals whose initial evaluation occurred in the institution's ED and whose echocardiogram was obtained either in the ED or within 24 hours of admission. Patients were placed in two cohorts-those remaining in their unit of admission without transfer (cohort WoT) and those transferred (cohort T) from their initial unit to one with a differing level of care within 24 hours. Pearson chi-square test assessed the relationship between echocardiogram status and appropriate bed placement, defined as no transfer within 24 hours.

Results

Of the 60 patients who met study criteria, no significant difference was detected in rates of transfer between patients whose echocardiograms were obtained in the ED versus those obtained within 24 hours of admission (odds ratio =2.08; 95% confidence interval: 0.58, 7.95; P=0.28).

Conclusions

Cardiac involvement is a known complication of MIS-C; however, our study yields no evidence in favor of obtaining echocardiograms in the ED to ensure appropriate bed placement. While this modality remains integral in evaluation and management, it does not appear to be requisite as part of an emergent workup prior to admission.

Long-term global longitudinal strain abnormalities in paediatric patients after multisystem inflammatory syndrome in children correlate with cardiac troponin T: a single-centre cohort study

BACKGROUND

Multisystem inflammatory syndrome in children is an inflammatory syndrome related to severe acute respiratory syndrome coronavirus 2 with a high risk of cardiovascular complications (vasoplegia, cardiac shock). We investigated the cardiac outcomes in multisystem inflammatory syndrome in children, focusing on the identification of predictors for late cardiac function impairment.

METHODS

Clinical characteristics, conventional echocardiography (left ventricle ejection fraction, fractional shortening), 4-chamber left ventricular global longitudinal strain, and cardiac MRI of multisystem inflammatory syndrome in children patients (n = 48) were collected during admission, 6 weeks, 6 months, >12-≤18 months, and >18-≤24 months post-onset. Paired over-time patterns were assessed and multivariable regression analyses were performed to identify predictors for late global longitudinal strain impairment.

RESULTS

In total, 81.3% of patients had acute cardiac dysfunction (left ventricle ejection fraction <50% and/or fractional shortening <28%). The left ventricle ejection fraction and fractional shortening reached a plateau level ≤6 weeks, while the global longitudinal strain continued to decrease in the first 6 months post-onset (median -17.3%, P < 0.001 [versus acute]). At 6 months, 35.7% of the patients still had an abnormal global longitudinal strain, which persisted in 5/9 patients that underwent echocardiography >12-≤18 months post-onset and in 3/3 patients >18-≤24 months post-onset. In a multivariable analysis, soluble troponin T (>62.0 ng/L [median]) was associated with reduced global longitudinal strain at 6 months. Our cardiac MRI findings indicated acute myocardial involvement (increased T1/T2 value) in 77.8% (7/9), which recovered quickly without signs of fibrosis on convalescent cardiac MRIs.

CONCLUSIONS

Late global longitudinal strain impairment is seen in some multisystem inflammatory syndrome in children patients up to one-year post-onset. Careful cardiac follow-up in patients with elevated troponin in the acute phase and patients with persistent abnormal global longitudinal strain is warranted until resolution of the global longitudinal strain since the long-term implications of such abnormalities are still unclear.

Longitudinal Cardiac Evaluation of Children with Multisystem Inflammatory Syndrome (MIS-C) Following COVID-19 by Conventional and Speckle-Tracking Echocardiography

Multisystem inflammatory syndrome in children (MIS-C), is a rare but severe, hyperinflammatory complication of COVID-19, in which cardiovascular abnormalities are frequently detected. In this prospective study, we describe the echocardiographic findings in patients with MIS-C, with the use of conventional Echocardiography and Speckle-Tracking Echocardiography (STE) with Left Ventricular (LV) Global Longitudinal Strain (GLS) analysis, in the acute and follow-up phase. In total, 25 MIS-C patients [64% females, mean (± SD) age: 8.3 (± 3.72) years] were included. In the acute phase, median (IQR) Troponin and NT-proBNP and mean heart rate, were 8.07 (14.52) pg/mL, 2875.00 (7713.00) pg/mL, and 102.87 (± 22.96) bpm, respectively. Median (IQR) LV Ejection Fraction (LVEF) was 66 (8)% and LVEF impairment was detected in 2/25 (8%) patients. On follow-up (mean time interval:9.50 ± 4.59 months), heart rate was significantly lower, with a mean value of 90.00 (± 14.56) bpm (p-value = 0.017). Median (IQR) LVEF was 66.00 (6.70)% (p-value = 0.345) and all 25 participants had normal LVEF. In 14/25 patients, additional LV-GLS analysis was performed. During the acute phase, mean LV-GLS was - 18.02 (± 4.40)%. LV-GLS was abnormal in 6/14 patients (42.9%) and among them, only one patient had reduced LVEF. On follow-up (median (IQR) time interval:6.93 (3.66) months), mean LV-GLS was -20.31 (± 1.91)% (p-value = 0.07) and in 1/14 patient (7.1%), the LV-GLS impairment persisted. In conclusion, in the acute and follow-up phase, we detected abnormal LV-GLS values in some patients, in the presence of normal LVEF, indicating that STE-GLS is a valuable tool for identifying subclinical myocardial injury in MIS-C.

Multisystem Inflammatory Syndrome in Children (MIS-C): Reduced Exercise Duration and Capacity at Six Month Follow-Up

Myocarditis is common in Multisystem Inflammatory Syndrome in Children (MIS-C), and the mechanism may differ from idiopathic/viral myocarditis as MIS-C involves a hyper-inflammatory state weeks after COVID-19. We sought to evaluate exercise stress testing (EST) in these patients as EST may help guide return-to-play recommendations. Retrospective cohort study evaluating ESTs (standard Bruce treadmill protocol) from MIS-C patients from 2020 to 2022, compared to myocarditis patients and age, sex, and weight matched controls from 2005 to 2019. ESTs included 22 MIS-C patients (mean age 11.9 years) with 14 cardiopulmonary and 8 cardiovascular tests, 33 myocarditis (15.5 years), and 44 controls (12.0 years). Percent-predicted peak VO2 was abnormal (< 80% predicted) in 11/14 (79%) MIS-C patients, 13/33 (39%) myocarditis, and 17/44 (39%) controls (p = 0.04). Exercise duration was shorter in MIS-C than myocarditis or control cohorts (p = 0.01). Isolated atrial or ventricular ectopy was seen in 8/22 (36%) MIS-C, 9/33 (27%) myocarditis, and 5/44 (11%) controls (p = 0.049). No arrhythmias/complex ectopy or evidence of ischemia were noted, though non-specific ST/T wave abnormalities occurred in 4/22 (18%) MIS-C, 5/33 (15%) myocarditis, and 3/44 (7%) controls. Exercise duration and percent-predicted peak VO2 were significantly reduced in MIS-C at mean 6-month follow-up compared to pre-COVID era idiopathic/viral myocarditis and control cohorts. This may be secondary to deconditioning during the pandemic and/or chronic cardiopulmonary or autonomic effects of COVID/MIS-C. Although there were no exercise-induced arrhythmias in our MIS-C patients, larger cohort studies are warranted. EST in MIS-C follow-up may help evaluate safety and timing of return to play and potentially mitigate further deconditioning.

Pediatric heart failure with preserved ejection fraction, a review

Diastolic dysfunction refers to a structural or functional abnormality of the left ventricle, resulting in impaired filling of the heart. Severe diastolic dysfunction can lead to congestive heart failure even when the left ventricle systolic function is normal. Heart failure with preserved ejection fraction (HFpEF) accounts for nearly half of the hospitalizations for acute heart failure in the adult population but the clinical recognition and understanding of HFpEF in children is poor. The condition is certainly much less frequent than in the adult population but the confirmatory diagnosis of diastolic dysfunction in children is also challenging. The underlying causes of HFpEF in children are diverse and differ from the main cause in adults. This review addresses the underlying causes and prognostic factors of HFpEF in children. We describe the pulmonary hypertension profiles associated with this cardiac condition. We discuss diagnosis difficulties in clinical practice, and we provide a simplified diagnostic algorithm for HFpEF in children.