We presented a cardiac work rate for one cycle cardiac based on the area of a Pressure Phase Plane, the velocity of activation and relaxation of the pressure curve, the interval of time and the variation of the pressu...We presented a cardiac work rate for one cycle cardiac based on the area of a Pressure Phase Plane, the velocity of activation and relaxation of the pressure curve, the interval of time and the variation of the pressure measurement on that cycle. We established an algebraic model to the Pressure Phase Plane area with a complete correlation of that model and the laboratory data for normal hypertensive and hypertrophied rat hearts (r = 0.99). We have obtained disjoint intervals for the cardiac work rate of the control group and the hypertrophied rat hearts as a consequence of the application of our algebraic model in those data acquisition.展开更多
Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency ...Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency cellular traction recovery. By applying a gradient-based digital image correlation method to track randomly distributed fluorescence microbeads on the deformed substrate induced by single cardiac myocyte, high-resolution substrate displacement field can readily be obtained. By using a numerical algorithm based on the integral Boussinesq solution, cell-substrate tractions are reconstructed in a stable and reliable manner. Finally, spatiotemporal dynamics of a single cardiac myocyte is investigated as it adheres to a polyacrylamide elastic substrate.展开更多
Purpose: Myocardial revascularization by coronary artery bypass grafting (CABG) in ischemic heart disease patients has direct impact on hemodynamic parameters in the immediate post-operative period. The peri-operative...Purpose: Myocardial revascularization by coronary artery bypass grafting (CABG) in ischemic heart disease patients has direct impact on hemodynamic parameters in the immediate post-operative period. The peri-operative cardiovascular functioning is an important determinant for outcome of surgery. In On-Pump CABG (ONCAB), the cardiopulmonary bypass has a negative effect on myocardium. Off-Pump CABG (OPCAB) avoids the effect of CPB but complete revascularization with difficult positioning of heart is technically demanding. This study is aimed to compare the cardiovascular functioning in the immediate post-operative period after OPCAB and ONCAB. Methods: Total 106 patients were operated for CABG from January 2015 to June 2016, of which 75 patients were operated for OPCAB and 31 patients were operated for ONCAB. For the comparison, hemodynamic parameters were measured during anesthesia before surgery, postoperatively after 1 and 4 hours (h) in the ICU, and in the morning after surgery, approximately after 20 h. Results: The time-dependent rise of hemodynamic parameters like Cardiac Output (CO), Cardiac Index (CI), Stroke volume (SV) and Left Ventricular Stroke Work Index (LVSWI) in the immediate post-operative hours (1 h and 4 h) are more predominant in OPCAB group than ONCAB group although the difference is eliminated mostly at 20 h. The better peripheral vasodilation after OPCAB causes immediate fall of Systemic Vascular Resistance Index (SVRI) after OPCAB. Conclusion: Better cardiovascular functioning immediately after OPCAB than ONCAB may be important for better hemodynamic stability. The difference is however eliminated after 24 hours indicating little significance in long term outcome.展开更多
基金supported by a scholarship from CAPESsupported by a grant from the CAPES,PRONEX/FAPES/CNPqsupported by grants from CAPES.
文摘We presented a cardiac work rate for one cycle cardiac based on the area of a Pressure Phase Plane, the velocity of activation and relaxation of the pressure curve, the interval of time and the variation of the pressure measurement on that cycle. We established an algebraic model to the Pressure Phase Plane area with a complete correlation of that model and the laboratory data for normal hypertensive and hypertrophied rat hearts (r = 0.99). We have obtained disjoint intervals for the cardiac work rate of the control group and the hypertrophied rat hearts as a consequence of the application of our algebraic model in those data acquisition.
基金supported by the National Basic Research Program (Grant No2007CB935602)the National Natural Science Foundation of China (Grant Nos90607004,10672005 and 10872008)
文摘Quantitative investigation on mechanical characteristics of cardiac myocytes has important physiological significance. Based on elastic substrate technique, this paper develops a set of algorithms for high-efficiency cellular traction recovery. By applying a gradient-based digital image correlation method to track randomly distributed fluorescence microbeads on the deformed substrate induced by single cardiac myocyte, high-resolution substrate displacement field can readily be obtained. By using a numerical algorithm based on the integral Boussinesq solution, cell-substrate tractions are reconstructed in a stable and reliable manner. Finally, spatiotemporal dynamics of a single cardiac myocyte is investigated as it adheres to a polyacrylamide elastic substrate.
文摘Purpose: Myocardial revascularization by coronary artery bypass grafting (CABG) in ischemic heart disease patients has direct impact on hemodynamic parameters in the immediate post-operative period. The peri-operative cardiovascular functioning is an important determinant for outcome of surgery. In On-Pump CABG (ONCAB), the cardiopulmonary bypass has a negative effect on myocardium. Off-Pump CABG (OPCAB) avoids the effect of CPB but complete revascularization with difficult positioning of heart is technically demanding. This study is aimed to compare the cardiovascular functioning in the immediate post-operative period after OPCAB and ONCAB. Methods: Total 106 patients were operated for CABG from January 2015 to June 2016, of which 75 patients were operated for OPCAB and 31 patients were operated for ONCAB. For the comparison, hemodynamic parameters were measured during anesthesia before surgery, postoperatively after 1 and 4 hours (h) in the ICU, and in the morning after surgery, approximately after 20 h. Results: The time-dependent rise of hemodynamic parameters like Cardiac Output (CO), Cardiac Index (CI), Stroke volume (SV) and Left Ventricular Stroke Work Index (LVSWI) in the immediate post-operative hours (1 h and 4 h) are more predominant in OPCAB group than ONCAB group although the difference is eliminated mostly at 20 h. The better peripheral vasodilation after OPCAB causes immediate fall of Systemic Vascular Resistance Index (SVRI) after OPCAB. Conclusion: Better cardiovascular functioning immediately after OPCAB than ONCAB may be important for better hemodynamic stability. The difference is however eliminated after 24 hours indicating little significance in long term outcome.
