tailieunhanh - Báo cáo y học: "Modeling left ventricular diastolic dysfunction: classification and key in dicators"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Modeling left ventricular diastolic dysfunction: classification and key in dicators. | Luo et al. Theoretical Biology and Medical Modelling 2011 8 14 http content 8 1 14 THEORETICAL BIOLOGY AND MEDICAL MODELLING RESEARCH Open Access Modeling left ventricular diastolic dysfunction classification and key in dicators Chuan Luo1 Deepa Ramachandran1 David L Ware2 Tony S Ma3 4 and John W Clark Jr1 Correspondence jWc@ 1Dept. Electrical and Computer Engineering Rice University Houston TX 77005 USA Full list of author information is available at the end of the article 2 BioMed Central Abstract Background Mathematical modeling can be employed to overcome the practical difficulty of isolating the mechanisms responsible for clinical heart failure in the setting of normal left ventricular ejection fraction HFNEF . In a human cardiovascular respiratory system H-CRS model we introduce three cases of left ventricular diastolic dysfunction LVDD 1 impaired left ventricular active relaxation IR-type 2 increased passive stiffness restrictive or R-type and 3 the combination of both pseudo-normal or PN-type to produce HFNEF. The effects of increasing systolic contractility are also considered. Model results showing ensuing heart failure and mechanisms involved are reported. Methods We employ our previously described H-CRS model with modified pulmonary compliances to better mimic normal pulmonary blood distribution. IR-type is modeled by changing the activation function of the left ventricle LV and R-type by increasing diastolic stiffness of the LV wall and septum. A 5th-order Cash-Karp Runge-Kutta numerical integration method solves the model differential equations. Results IR-type and R-type decrease LV stroke volume cardiac output ejection fraction EF and mean systemic arterial pressure. Heart rate pulmonary pressures pulmonary volumes and pulmonary and systemic arterial-venous O2 and CO2 differences increase. IR-type decreases but R-type increases the mitral E A ratio. PN-type produces the well-described pseudo-normal mitral inflow pattern. All