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Right ventricular diastolic filling in the first day of life
K Harada1, T Shiota, Y Takahashi
1Department of Pediatrics, Akita University School of Medicine, Japan.
Insights
Right ventricular inflow patterns change significantly in neonates within 24 hours of birth. Increased preload, influenced by ductus arteriosus closure, affects diastolic filling, impacting flow interpretation.
Area of Science:
- Neonatal Cardiology
- Pediatric Echocardiography
- Hemodynamics
Background:
- Right ventricular (RV) diastolic function is crucial in neonates.
- Understanding RV inflow patterns requires assessing preload effects.
- Doppler echocardiography is a key tool for evaluating neonatal hemodynamics.
Purpose of the Study:
- To investigate how changes in preload affect the Doppler flow patterns of RV inflow in the first 24 hours of life.
- To correlate these flow patterns with hemodynamic changes, specifically ductus arteriosus patency.
Main Methods:
- Serial Doppler echocardiography was performed on 16 normal neonates at 2, 12, and 24 hours of age.
- Measurements included pulmonary artery (PA) flow velocity-time integral and total transtricuspid flow velocity-time integral (E area and A area).
- Data were analyzed using a computer-interfaced digitizer pad.
Main Results:
- Significant increases in PA flow velocity-time integral, total transtricuspid flow velocity-time integral, E area, and A area were observed by 24 hours compared to 2 hours.
- Peak E/A ratio and E/A area ratio showed no significant changes.
- Smaller ductus arteriosus size correlated inversely with peak E, E area, and A area, suggesting reduced left-to-right shunting.
Conclusions:
- The observed increase in RV preload by 24 hours is likely due to the cessation of left-to-right shunting through the ductus arteriosus.
- RV early and late diastolic filling patterns are dependent on preload.
- Interpreting transtricuspid velocity patterns requires consideration of preload-induced flow redistribution for accurate diastolic function assessment.
Abstract:
To evaluate the effects of altered preload on the Doppler flow pattern of right ventricular inflow in the first day of life, serial Doppler echocardiography of the pulmonary artery (PA) and tricuspid valve was performed in 16 normal neonates at 2, 12, and 24 hr. A computer-interfaced digitizer pad was utilized to measure the followings: PA flow velocity-time integral, total transtricuspid flow velocity-time integral, flow velocity-time integral of early diastolic filling (E area), and flow velocity-time integral of atrial contraction (A area). The PA flow velocity-time integral, total transtricuspid flow velocity-time integral, E area, A area, peak E, and peak A were increased significantly by 24 hr compared with the values at 2 hr of age. However, the peak E/A, E/A area and peak E/total transtricuspid flow velocity-time integral did not show significant changes from 2 to 24 hr. The ductus arteriosus size was inversely correlated with the peak E (r = -0.46, p < 0.05), E area (r = -0.37, P < 0.05), and A area (r = -0.34, p < 0.05). Therefore, the increase in right ventricular preload at 24 hr is considered to be due to the cessation of the left-to-right shunt through the ductus arteriosus. These results suggest that the pattern of early and late diastolic filling of the right ventricle were dependent on the increase in preload. We can therefore conclude that the redistribution of transtricuspid flow induced by the preload condition should be taken into account to interpret the transtricuspid velocity pattern in terms of diastolic function.