Ergebnisse mathematischer Frequenzanalysen von ersten Herztönen im Tierexperiment

Zusammenfassung

Durch frequenzanalytische Untersuchungen an Herztönen von Hunden in Narkose ließ sich ein einheitlicher Aufbau des ersten Herztones in zwei Grundton-Oberton-Komplexe in ganzzahligem Verhältnis nachweisen, die durch die Aortenklappenöffnung voneinander getrennt sind. Dieses Schema war auch durch arterielle Drucksteigerung und Drucksenkung nicht zu beeinflussen.

Die Untersuchungen lassen den Schluß zu, daß die Schallquelle der aufgefundenen Grundton-Oberton-Komplexe der linke Ventrikel ist, der als Kugelstrahler gelten kann. Die Tonschwingungen entstehen zum Beginn der isometrischen Kontraktion und zu Beginn der Austreibung.

Summary

Phonocardiographic recordings together with right and left ventricular pressure tracings were obtained from anesthetized mongrel dogs and analysed by the mathematical method of “Progressive Analyse” (Stumpff; Marth and v.Egidy).

The first heart sound proved to consist of two different fundamental frequencies with each a varying set of simple harmonics, the first fundamental frequency following the onset of left ventricular pressure rise being always of a little higher pitch than the second. The limit between these two vibratory complexes was a sharp line coinciding through all filter channels. It fell together with the aortic valve opening as judged by the maximum of rate of change of left ventricular pressure (maximumdp/dt). There was no obvious relation between the two vibratory complexes and right ventricular hemodynamic events.

This scheme of both frequency pitch and structure of the first heart sound proved to be invariant to rising and decreasing arterial pressure induced by norepinephrine or Hydergin^®.

These results confirm the theory, that the first heart sound is generated by the left ventricle and that the two parts of the first heart sound are generated consecutively by both the phase of isometric ventricular contraction and the beginning of the ejection period, whereas the right ventricle does not contribute noticeably to the first heart sound under normal conditions.