[Effect of premedication in general anesthesia on periodic variability of heart rate]. / Untersuchungen zum Einfluss der Prämedikation bei Allgemeinnarkosen auf die periodische Variabilität der Herzfrequenz.

During the premedication phase the temporary course of the sinus arrhythmia was studied on 10 patients without cardiocirculatory diseases undergoing insufflation anaesthesia. The progress of heart rate variability was observed in periodic components by calculation of power density spectra. The results reveal a significant decrease of the spontaneous variations of the heart rate after 40 to 50 minutes action of atropine and pethidine. Periodic components of respiration and circulation are more reduced than long wave spectral ranges. Their residue is a measure for the size of the inhibition of the vagal impulse. The inverse atropine effect is preponderantly to be observed in periodic components of respiration and circulation. About 30 minutes after the injection of the premedication mixture a new steady state was found concerning the circulatory and respiratory rhythm.

[The effect of the tidal volume on the sinus arrhythmia of the heart]. / Zum Einfluss der Atemtiefe auf die Sinusarrhythmie des Herzens

The sinus arrhythmia of the human heart was investigated in its relation to the tidal volume under resting conditions in the course of the day, in voluntarily changed tidal volume, under atropine medication and during physical work. In resting conditions it was found that nearly 40% of the sinus arrhythmia is of respiratory origin, and that no respiratory influence is demonstrable any longer at sufficient doses of atropine. Under physical load, the sinus arrhythmia is diminished in spite of the enlarged tidal volume. In this case, an additional smoothing influence to the sinus arrhythmia has to be assumed.

A comparison between noninvasive and bloody methods for use in the continuous estimation of cardiac contractility.

Simultaneous measurements of the blood pressure in arteria carotis with a catheter device and a new noninvasive continuously recording method were carried out in 7 rabbits with a chronically isolated arteria carotis loop. Results show good correspondence between both methods for pulse curve and blood pressure over a long period and a wide range,as well as good reproducibility. An absolute calibration for the noninvasive method is impossible. The new method is quite suitable for studying the dynamics of pressure pulse and pressure behavior.