Global Longitudinal Strain Reduction in the Absence of Clinical Cardiac Symptoms in Multisystem Inflammatory Syndrome in Children Associated with COVID-19: A Case Series.

Multisystem inflammatory syndrome in children is a term that encompasses the systemic inflammation seen in children 4-6 weeks following COVID-19 infection. Cardiac involvement is common in this condition and can range from mild myocarditis to severe hypotension and cardiogenic shock, but not all patients display overt cardiac symptoms. We present three such patients who presented with a variety of systemic inflammatory symptoms but lacked apparent cardiac symptoms, and all had normal left ventricular ejection fraction but reduced global longitudinal strain (GLS). GLS is a cardiac tissue deformation index measured by Echocardiography to detect early changes in global function even before changes in ejection fraction are seen. We suggest this finding may indicate subclinical myocardial injury and stress the need for closer evaluation and follow-up for these patients as well as further research on both the short- and long-term effects of COVID-19 on cardiac function in the pediatric population.