Human Fetal Hearts with Tetralogy of Fallot have Altered Fluid Dynamics and Forces.

In this study, we performed patient-specific ultrasound-based flow simulations of 3 TOF and 7 normal human fetal hearts. TOF right ventricles (RV) had smaller end-diastolic volumes (EDV) but similar stroke volumes (SV), while TOF left ventricles (LV) had similar EDV but slightly increased SV compared to normal ventricles. Simulation showed that TOF ventricles had elevated systolic intra-ventricular pressure gradient (IVPG), and required additional energy for ejection, but IVPG elevations were considered to be mild relative to arterial pressure. TOF RV and LV had similar pressures due to equalization via ventricular septal defect (VSD). Further, relative to normal, TOF RVs had increased diastolic wall shear stresses (WSS), but TOF LVs were not. This was caused by high tricuspid inflow that exceeded RV stroke volume, leading to right-to-left shunting and chaotic flow with enhanced vorticity interaction with the wall to elevate WSS. Two of the three TOF RVs but none of the LVs had increased thickness. As pressure elevations were mild, we hypothesized that pressure and WSS elevation could play a role in the RV thickening, among other causative factors. Finally, the endocardium surrounding the VSD consistently experienced high WSS due to RV-to-LV flow shunt and high flow rate through the over-riding aorta. PMID: 30216114 [PubMed - as supplied by publisher]
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Tags: Am J Physiol Heart Circ Physiol Source Type: research