Input Impedance of the Systemic Circulation

Input impedance of the systemic circulation.

Input impedance of the systemic circulation in man.

To determine the systemic input impedance, pulsatile pressure and flow were measured in the ascending aorta in 16 human subjects who were undergoing diagnostic cardiac catheterization. Blood flow was measured with a catheter-tip electromagnetic velocity meter, and pressure with an external transducer connected with the fluid-filled lumen of the catheter. Five subjects were found to have no evid...

Noninvasive input impedance of the human systemic circulation.

Noninvasive Input Impedance of the Human Systemic Circulation To the Editor: The study of noninvasive aortic input impedance by Segers et al1 is a very important step in understanding age-related changes in humans and an advance on previous limited invasive studies conducted decades ago.2,3 One reason that these lapsed was the difficulty in accurately measuring aortic pulsatile flow, attributab...

The influence of mock circulation input impedance on valve acceleration during in vitro cardiac device testing.

For a mechanical heart valve, a strong spike in pressure during closing is associated with valve wear and erythrocyte damage; thus, for valid in vitro testing, the mock circulation system should replicate the conditions, including pressure spikes, expected in vivo. To address this issue, a study was performed to investigate how mock circulation input impedance affects valve closure dynamics. A ...

Input impedance of the pulmonary arterial system in normal man. Effects of respiration and comparison to systemic impedance.

Input impedance of the pulmonary arterial system was determined in 10 subjects undergoing elective cardiac catheterization. No cardiovascular or pulmonary disease was found in these patients. In five of the subjects, systemic arterial impedance was also obtained, so that both systems could be compared. Pulmonary and systemic peripheral resistances were 79 +/- 9 dynes sec/cm5 (mean +/- SEM) and ...