Stanley E Rittgers

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Diastolic time (DT) is calculated as the cycle length (RR) minus electromechanical systole (QS2). The ratio of DT (RR-QS2) to RR interval times 100, or the percent diastole (%D), varies nonlinearly with heart rate (HR), increasing rapidly with decreasing HR. The effect of commonly used cardioactive agents on %D was studied in five groups of normal subjects.(More)
OBJECTIVE The purpose of this study was to simultaneously monitor the transcriptional levels of 12 endothelial growth factor genes in response to alterations in wall shear stress (WSS) under conditions relevant to the development of intimal hyperplasia, a major cause of arterial bypass graft failure. METHODS Human umbilical vein endothelial cells were(More)
Due to the relatively limited amount of work done to date on developing prosthetic vein (as opposed to cardiac) valves, advances in this topic require progress in three distinct areas: 1) improved device design, 2) relevant device testing conditions, and, 3) appropriate parameters for evaluation of results. It is the purpose of this paper to address two of(More)
In vivo wall shear rates have been obtained based on estimates from either volume flow rate or single-point velocity measurements along with the wall no slip assumption and a simple linear regression. Recent results [19] have shown that, under pulsatile flow conditions, wall shear rates are more accurately predicted by using up to four velocity points and a(More)
BACKGROUND Chronic venous insufficiency is a serious disease for which there is no clearly successful surgical treatment. Availability of a proven prosthetic vein valve could provide such an option by reducing venous reflux while permitting normal antegrade flow. METHODS A new prosthetic vein valve design has been developed which mimics the function of a(More)
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