Pulsewave velocity

Homocysteine may contribute to systolic hypertension and cardiac events by decreasing conduit artery compliance and inducing endothelial dysfunction. The effects of the experimental induction of hyperhomocysteinemia on systemic arterial compliance and pulsewave velocity are unclear, with contradictory results from previous studies. The investigators tested whether oral methionine impairs brachial artery compliance in addition to endothelial function.

We aimed to validate a new method for measuring arterial pulsewave transit time and pulsewave velocity (a measure of arterial elasticity), based on the principle of photoplethysmography (PPG), and to compare transcutaneous values with those obtained by intra-arterial measurements. Three validation experiments are described. (a) PPG pulse wave delay times (defined as the time interval between the ECG R wave and the foot of the arterial pulse wave measured at the wrist or ankle) were compared to values obtained simultaneously from an established methodology (Doppler ultrasound)...

Pulsewave velocity analysis is an option for the noninvasive determination of cardiac output and the evaluation of additional haemodynamic parameters. An algorithm we developed ourselves has been established as a method for the measurement of cardiac output in rabbits. The effectiveness of this program was investigated by monitoring controlled hypoxia-induced alterations in the circulatory system. Calculated values were compared with direct measurements of cardiac output with a Doppler flow probe placed in the ascending aorta...

A one-dimensional intravascular MR (IVMR) technique for the measurement of pulsewave velocity in a single cardiac cycle is presented. The technique was used to measure pulsewave velocity in vivo in the intact rabbit model, where its sensitivity to different hemodynamic states was demonstrated using a pharmacological intervention with phenylephrine and nitroprusside. IVMR measurements of pulsewave velocity were found to increase with mean arterial pressure, as expected. Further, IVMR-based pulsewave velocity estimates were in agreement with those measured by pressure catheters and direct distensibility measurement...

A clinical study was conducted to examine the effects of depression on cardiac autonomic control. Cardiac autonomic control was measured in 26 nonmedicated patients (19 females) suffering from Major Depression, melancholic type, and in 26 age- and sex-matched normal controls. We measured heart rate and high frequency heart rate variability (respiratory sinus arrhythmia), pulsewave velocity and blood pressure, during 10 min of supine rest under controlled conditions. Using a log transformed time domain measure of respiratory sinus arrhythmia (logRSA), we found an inverse linear dependence between cardiac vagal tone and age in the healthy subjects as well as the depressed patients...

A new, one-dimensional method for the measurement of pulsewave velocities using real-time magnetic resonance (MR) imaging is presented. The measurement sequence is essentially of a RACE-type (Real Time Acquisition and Evaluation) with interleaved acquisition in two not necessarily parallel slices. In each slice the blood flow velocity perpendicular to the slice orientation was monitored. From the relative time difference of blood flow activity and the slice distance, pulsewave velocities were calculated. With a time resolution of 13 ms an overall acquisition time of 3...

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The present investigation sought to determine the extent to which primary changes in mean arterial pressure (MAP) might influence the calculated aortic impedance. In seven open-chest, anesthetized, autonomically blocked dogs, we measured aortic impedance using white-noise analysis at various levels of MAP achieved by adjusting the height of a left atrial reservoir rather than by pharmacological intervention. Impedance spectra so obtained were parameterized according to best-fit wind-kessel models (Ra, Rc, Ca) and three parameters to characterize wave reflections: the frequency at which the phase of the impedance approached or crossed through 0 degree (phi 0), the frequency of the first minimum of the impedance modulus (fmin), and the amplitude of the first oscillation of the impedance modulus (a 1)...

It was possible in a controlled double-blind study to demonstrate by means of dynamographic measurements the action of raubasine in patients with cerebrovascular disorders. A new formulation of Lamuran tablets (MF706d) was used for the investigation. This formulation has an improved in-vitro dissolution rate for raubasine that is largely independent of pH. In the raubasine group (10 patients aged 47 to 81 years, including 6 cases of anacidity) there was after one and two weeks treatment with dialy doses of 90 mg raubasine a significant reduction of the raised vascular resistance and pulsewave velocity and systolic blood pressure in the internal carotid artery which indicate an improvement in cerebral haemodynamics...

Pulsatile haemodynamics associated with graded degrees of experimentally produced stenosis were studied in the canine femoral artery. Invasively determined pulsatile blood flow and noninvasively determined blood velocity with Doppler ultrasound were measured an average of 1.3 and 2.3 cm proximal to the stenosis, respectively. Pulsatile blood pressure was measured 0.6 cm proximal and 3.7 cm distal to the stenosis. With increasing severity of stenosis there were progressive increases in the femoral artery hydraulic input impedance moduli and in the ratio of the impedance moduli to the zero harmonic impedance (or total resistance)...