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  • 1
    Electronic Resource
    Electronic Resource
    The impact of cardiac activity on triaxially recorded endogenous microvibrations of the body (1980)
    Springer
    European journal of applied physiology 44 (1980), S. 83-96 
    Details
    ISSN: 1439-6327
    Keywords: Microvibrations ; Cardiac activity ; Isoprenaline ; Exercise ; Cold stress ; Muscle tonus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of cardiac activity on the endogenous microvibrations of the body (MV) was studied in a total of 37 young, healthy subjects. The force oscillations and the rectified and integrated force-time function in the three space directions were simultaneously recorded with the ECG and the arterial pulse during quiet bipedal standing before (control) and after isoprenaline inhalation, a work load of 150 W, and mild cold stress. In the vertical force component (Fz) 27 out of the 37 subjects showed cardiac characteristics similar to the ballistocardiogram. After isoprenaline or exercise, all 37 subjects showed these cardiac characteristics in Fz, and the maximal amplitudes as well as the rectified impulse values were increased in the three directions, but particularly in the z-axis. The propagation of the MV through the body was independent of the arterial pulsation. The increase in muscle tone due to cold stress led to a significant increase of the rectified impulse only in the sideward direction (SY). It is concluded that the triaxially recorded MV arise from cardiac activity, mainly reflected in the vertical (z) axis, and from skeletal musculature representing a mechanical oscillating system with varying material constants (muscle tension, inertial forces, etc.).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00421767
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The ECG changes due to altitude and to catecholamines (1984)
    Springer
    European journal of applied physiology 53 (1984), S. 35-42 
    Details
    ISSN: 1439-6327
    Keywords: Altitude ; Aerohypoxia ; Isoprenaline ; Beta-receptor blockade ; ECG changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to distinguish the effects of beta-receptor stimulation on the ECG from other factors during short-term adjustment to hypoxic aerohypoxia, the ECG of 19 volunteers were compared during moderately acute, stepwise exposure to high altitude (6,000 m) in a low pressure chamber, once with and once without beta-receptor blockade (propranolol), and after isoprenaline inhalation at ground level. The results show that beta-receptor stimulation accounts mainly for most ECG changes during altitude exposure, i.e., for the shortening of R-R interval, the lengthening of Q-T and in particular for the ST-T flattening, the latter therefore being only an indirect sign of hypoxia. After exclusion of the catecholamines, the minor but still significant ECG changes at altitude (shortening of R-R interval, increase of P wave, prolongation of P-Q, deviation of the R vector, T wave flattening in the left precordial leads) may be attributed to other, so far undefined factors, such as cardiac hypoxia, vagal withdrawal, or increase of pulmonary resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00964687
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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