FOURIER ANALYSIS OF KOROTKOFF VIBRATIONS.

Abstract : Blood pressure measurements were made on two subjects, a healthy subject and a patient in clinical shock in whom the Korotkoff sounds were absent. The Korotkoff vibrations were detected by a piezoelectric transducer and recorded during a blood pressure measurement cycle on each subject. The Korotkoff vibrations were digitized and spectral analysis performed using the fast Fourier transform algorithm. Results of this experiment demonstrate that characteristic Korotkoff vibrations are detectable in hypotensive subjects even when the Korotkoff sounds are absent. The amplitude-frequency spectrum of these detected Korotkoff vibrations show abrupt changes in character as cuff pressure is reduced. In the normo-tensive subject, abrupt changes were found to occur at the systolic and diastolic indices. (Author)