Diastolic Parameters
Diastolic dysfunction is characterized by decreased E/A,
Em/Am, E/Em ratio,
prolonged E DT, and prolonged IVRT [12]. MPI is the ratio of time
interval that is proved to be reliable method for the evaluation of both
systolic and diastolic functions, not depending volume and pressure
conditions of ventricles, and high heart rate [13]. Goncu et al.
found mitral E/A ratio significantly lower in pregnant women that
recovered moderate COVID-19 infection [21]. Similarly, we found both
mitral and tricuspid E/A ratios, in addition Em,
Em/Am values of COVID-19 group
significantly lower both in prenatal and postnatal period. MEDT, TEDT,
IVRT of LV and RV lateral walls were significantly longer in fetal
period. IVRT of all segments were significantly prolonged in postnatal
echoes. These findings demonstrate that diastolic dysfunction of both
ventricles, which started with wall thickening in post-COVID fetal life,
continues in the infancy. These findings may be the long-term negative
effects of the maternal COVID-19.
Placental SARS-CoV-2 infection can lead to massive local inflammation
with the formation of fibrin deposits, thus, fetal and subsequent
neonatal distress due to placental dysfunction caused by placental
immunological findings and inflammation may transiently have a clinical
course resembling the fetal presentation of SARS-CoV-2-associated MIS-N
[5]. Although the hyperinflammatory response developing in the
neonatal period with perinatal asphyxia is associated with enlargement
of the coronary arteries, severe myocardial dysfunction and left
ventricular dilatation, it has thought to be related with neonatal
myocarditis [24].
Gestational/pregestational diabetes mellitus has been used as a model of
fetal diastolic dysfunction due to myocardial hypertrophy and the
consequent reduction of ventricular compliance. In this respect, as a
result of an increased myocardial mass and left ventricular hypertrophy,
fetuses of diabetic mothers may have a higher preload than normal
controls. Significantly lower E/Em ratios were observed
in both atrioventricular valves in fetuses of diabetic mothers when
compared to control fetuses. This is the result of higher myocardial
velocities at the mitral and tricuspid annuluses, rather than because of
changes in early atrioventricular diastolic flows. In the fetus, the
impaired ventricular diastolic function as a result of decreased
relaxation and compliance occurring in maternal diabetes seems to prompt
higher myocardial velocities in the atrioventricular annuluses, in order
to counter the limited ventricular distensibility in early diastole
[22]. Similar to this hypothesis, myocardial velocities of three
segments were found to be significantly higher, mitral and tricuspid
E/Em ratios were significantly lower in the fetal period
in our study. These findings did not persist postnatally except
Em. Because of persisting wall thickening and decreased
compliance, Em remained significantly low on the
postnatal long-term.