Peristaltic-Like Motion of the Human Fetal Right Ventricle and its Effects on Fluid Dynamics and Energy Dynamics
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In both adult human and canine, the cardiac right ventricle (RV) is known to exhibit a peristaltic-like motion, where RV sinus (inflow region) contracts first and the infundibulum (outflow region) later, in a wave-like contraction motion. The delay in contraction between the sinus and infundibulum averaged at 15% of the cardiac cycle and was estimated to produce an intra-ventricular pressure difference of 15 mmHg. However, whether such a contractile motion occurs in human fetuses as well, its effects on hemodynamics remains unknown, and are the subject of the current study. Hemodynamic studies of fetal hearts are important as previous works showed that healthy cardiac development is sensitive to fluid mechanical forces. We performed 4D clinical ultrasound imaging on eight 20-weeks old human fetuses. In five fetal RVs, peristaltic-like contractile motion from the sinus to infundibulum (“forward peristaltic-like motion”) was observed, but in one RV, peristaltic-like motion was observed from the infundibulum to sinus (“reversed peristaltic-like motion”), and two RVs contraction delay could not be determined due to poor regression fit. Next, we performed dynamic-mesh computational fluid dynamics simulations with varying extents of peristaltic-like motions for three of the eight RVs. Results showed that the peristaltic-like motion did not affect flow patterns significantly, but had significant influence on energy dynamics: increasing extent of forward peristaltic-like motion reduced the energy required for movement of fluid out of the heart during systolic ejection, while increasing extent of reversed peristaltic-like motion increased the required energy. It is currently unclear whether the peristaltic-like motion is an adaptation to reduce physiological energy expenditure, or merely an artefact of the cardiac developmental process.
KeywordsHuman fetus Right ventricle Peristaltic motion Fluid mechanics Ventricular vortex Wall shear stress
The authors thank the National University of Singapore Young Investigator Award, grant entitled “Fluid Mechanics and Mechanobiology of Congenital Cardiac Outflow Tract Malformations” (PI: Yap) for funding, and the National University of Singapore Graduate School of Integrated Sciences and Engineering Scholarship for funding support for the lead author, Hadi Wiputra.
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- 2.Armour, J., J. Pace, and W. Randall. Interrelationship of architecture and function of the right ventricle. Am. J. Physiol.-Leg. Content 218:174–179, 2016.Google Scholar
- 6.Kenny, J. F., T. Plappert, P. Doubilet, D. H. Saltzman, M. Cartier, L. Zollars, G. Leatherman, and M. S. J. Sutton. Changes in intracardiac blood flow velocities and right and left ventricular stroke volumes with gestational age in the normal human fetus: a prospective Doppler echocardiographic study. Circulation 74:1208–1216, 1986.CrossRefPubMedGoogle Scholar
- 11.Moss, A. J., and F. H. Adams. Heart Disease in Infants, Children, and Adolescents. Baltimore: Williams & Wilkins Company, 1968.Google Scholar
- 12.Paladini, D., M. Vassallo, G. Sglavo, C. Lapadula, and P. Martinelli. The role of spatio-temporal image correlation (STIC) with tomographic ultrasound imaging (TUI) in the sequential analysis of fetal congenital heart disease. Ultrasound Obstet. Gynecol. 27:555–561, 2006.CrossRefPubMedGoogle Scholar
- 13.Raines, R., M. LeWinter, and J. Covell. Regional shortening patterns in canine right ventricle. Am. J. Physiol.-Leg. Content 231:1395–1400, 1976.Google Scholar
- 15.Steinman D. and L. Antiga. VMTK-Vascular Modeling Toolkit. Webpage, 2008.Google Scholar
- 17.Tworetzky, W., L. Wilkins-Haug, R. W. Jennings, M. E. van der Velde, A. C. Marshall, G. R. Marx, S. D. Colan, C. B. Benson, J. E. Lock, and S. B. Perry. Balloon dilation of severe aortic stenosis in the fetus potential for prevention of hypoplastic left heart syndrome: candidate selection, technique, and results of successful intervention. Circulation 110:2125–2131, 2004.CrossRefPubMedGoogle Scholar
- 18.Wiputra, H., C. Q. Lai, G. L. Lim, J. J. W. Heng, L. Guo, S. M. Soomar, H. L. Leo, A. Biwas, C. N. Z. Mattar, and C. H. Yap. Fluid mechanics of human fetal right ventricles from image-based computational fluid dynamics using 4D clinical ultrasound scans. Am. J. Physiol.-Heart Circ. Physiol. 311:H1498–H1508, 2016.CrossRefPubMedGoogle Scholar