Viscoelasticity of biological materials - measurement and practical impact on biomedicine.

Mechanical behavior of biological structures under dynamic loading generally depends on elastic as well as viscous properties of biological materials. The significance of "viscous" parameters in real situations remains to be elucidated. Behavior of rheological models consisting of a combination of inertial body and two Voigt's bodies were described mathematically with respect to inverse problem solution, and behavior in impulse and harmonic loadings was analyzed.

A new method of estimation of the optimal AV delay by using pulse oximetry in DDD paced patients.

The paper gives a detailed description of a new method for estimating the optimal AV delay in dual chamber paced patients, which is non-invasive, not dependent on the examinator, not time consuming and inexpensive. In principle, the pulse oximetry signal obtained by common finger probe was used to measure the change in its time course after changes in pacemaker stimulation. The Eagle 4000 monitor, manufactured by Marquette USA, was used for measurements and digitizing the data and then this data was analyzed using a portable personal computer with original programs developed in Famulus v.

Atrial contribution to ventricular ejection in sequentially paced patients.

A new method for quantitative assessment of the atrial contribution to ventricular ejection in sequentially paced patients is described. The atrial contribution (AC) has been defined as the pulse pressure decrement (invasive arterial measurement by a canulla inserted into the brachial artery), expressed in percent of the control pulse pressure, induced by switching off the atrium activating impulse for one beat. In 17 patients, the AC was found to be atrioventricular (AV) interval dependent, the measurements were well reproducible (the mean difference between two measurements at different times was 93%, S.

[Aortic stenoses and pulmonary hypertension].

Authors have been catheterized a total of 36 patients with isolated aortal stenosis. In 14 from them (38%), the mean pression value in pulmonar artery was ranged as over 25 torrs (3.33 kPa).