title: Flow patterns in three-dimensional left ventricular systolic and diastolic flows determined from computational fluid dynamics.
abstract: A realistic model of the left ventricle of the heart was previously constructed, using a cast from a dog heart which was in diastole. Previous studies of the three-dimensional heart model were conducted in systole only. The purpose of this investigation was to extend the model to both systole and diastole, and to determine what the effect of a previous cardiac cycle was on the next cardiac cycle. The 25.8 cc ventricular volume was reduced by 40% in 0.25 seconds, then increased to the original volume in another 0.25 seconds and then allowed to rest for 0.25 seconds. Runs done with an ejection fraction of 60% showed little variation from one cardiac cycle to another after the third cardiac cycle was completed; the maximum velocity could vary by over 30% between the first and second cardiac cycles. In systole, centerline and cross-sectional velocity vectors greatly increased in magnitude at the aortic outlet. Most of the pressure drop occurred in the top 15% of the heart. The diastolic phase showed complex vortex formation not seen in the systolic contractions; these complex vortices could account for experimentally observed turbulent blood flow fluctuations in the aorta.
authors.affiliation: Department of Bio-Medical Engineering, School of High-Technology for Human Welfare, Tokai University, Shizuoka, Japan.
authors.forename: T W
authors.initials: TW
authors.lastname: Taylor
authors.forename: T
authors.initials: T
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D003198:Computer Simulation; D003971:Diastole; D004285:Dogs; D008955:Models, Cardiovascular; D012039:Regional Blood Flow; D013318:Stroke Volume; D013599:Systole