Natural shear waves show sequential changes in myocardial stiffness In paediatric multi-inflammatory systemic syndrome post COVID

Abstract

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Egyptian ministry of research and higher education Background Multi-inflammatory systemic syndrome post COVID infection (MIS-C) in children causes myocarditis and affects myocardial diastolic function. Recent high frame rate echocardiography allows to assess myocardial shear waves (SW). SW are mechanical waves generated by mitral and aortic valve closure (MVC & AVC). Their propagation velocities are related to myocardial stiffness (MS), a determinant of diastolic function. Nevertheless, this has not yet been tested in paediatric cardiology and in this pathology. Purpose This study aimed at exploring the changes in natural SW propagation velocity as measure of myocardial diastolic properties in paediatric patients with MIS-C. Methods Seven MIS-C children (mean age 6.7 ±3.6 years) were prospectively followed over 6 months (group A). As a control group; one hundred-four healthy volunteers (HV) (mean age 10.2 ±4.4 years) were recruited (group B). High-frame rate echocardiography was used to obtain parasternal long axis views of all subjects at a frame rate of 1580 ±113 Hz. An anatomical M-mode was drawn along the interventricular septum and Tissue Doppler acceleration maps were extracted to measure SW propagation speed after MVC and AVC (Figure 1). Independent sample t-test was used to compare between both groups. Repeated measures analysis of variance (ANOVA) was used to show sequential changes during follow-up. Results SW propagation velocities were significantly higher among MIS-C patients than in HV group after both MVC (4.3 ±0.6 m/s vs 2.8 ±0.3 m/s respectively, p<0.001) and AVC (5.2 ±0.6 m/s vs 3.0 ±0.3 m/s respectively; p<0.001). Interestingly, SW propagation speeds in MIS-C patients declined significantly with myocardial recovery during course of disease (figure 2) and normalised 6 months post discharge (MVC: 2.9 ±0.3 m/s; P<0.001, AVC: 3.2 ±0.4 m/s; P<0.001) compared to admission. Conclusions SW speed found to be 1.5 to 1.7 fold higher with myocardial inflammation in MIS-C patients compared to HV. Values normalised within 6 months. These findings indicate that SW velocities can show sequential changes in the course of a disease and suggest that SW imaging has potential to serve as a new non-invasive diagnostic tool in paediatric cardiac diseases.