Myocardial properties

Whether or not the in vitro test results of the myocardial properties are applicable for the in vivo cardiac analyses remains as a heated debate topic. As has already been discussed earlier, the finite element models enable te myocardial passive and active characteristics to be estimated in vivo. It is an inverse problem of knowing the loading and the consequent deformation and of continuously guessing the material properties until the simulated and measured deformations are approximately matched. 

So far, only the methods for estimating the global or average values of the myocardial fiber properties for a silhouette or a cross section of the ventricle have been proposed. In a later section, a method based on a blood-myocardium composite model will be discussed for the in vivo estimate of the regional myocardial properties. 

Preanesthetic drugs may be omitted in those 60 years or older because many of the medical disorders for which these drugsare contraindicated are seen in older individuals For example, atropine and glycopyrrolate, drugs that can be used to decrease secretions of the upper respiratory tract, are contraindicated in certain medical disorders such as prostatic hypertrophy, glaucoma, and myocardial ischemia. Other preanesthetic drugs that depress the central nervous astern (CN, such as narcotics barbiturates and antianxiety drugs with or without antiemetic properties may be contraindicated in the older individual. 

Electrophysiological Experiments. Guinea pig myocardial cells prepared as described previously 24) were superfused at 37 C with a Tyrode solution. Electrical properties of the myocytes were examined by the patch-clamp methods (25) using fire-polished pipettes. The current was measured by means of a patch-clamp amplifier, stored on the tape through a digital PCM data recording system, and analyzed with a computer. 

Myocardial infarction, 3 710-711 and blood coagulation, 4 81 Myocardial pacemaker cells, 5 81 Myocardium, 5 79—80 Myoglobin, properties of standard, 3 836t Myosin, role in heart excitation and contraction coupling, 5 81 Myrac aldehyde, 2 278 24 485 Myrascone, 24 571... 

Aggregation of blood platelets is the requisite first event for the maintenance of intact circulation in the face of any break in a blood vessel. It is the platelet clump that starts the long and complicated process leading to closure of the broken vessel by an organized blood clot. Though this property of platelets is vital to maintenance of the circulatory system, an excessive tendency to aggregation can also lead to problems. Thus platelet clumps formed in blood vessels in the absence of injury can lead to blockade of blood circulation and subsequent injury. Strokes and some types of myocardial infarcts have thus been associated with platelet clumps. The nonsteroid antiinflammatory... 

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