Computer determination of systolic time intervals based on impedance cardiography

N. Szilágyi, Eszter Láng, László Balázs

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A computerized system has been developed based on impedance cardiography for processing systolic time intervals (STI) in psychophysiological experiments. The conventional method of STI determination is based on transducing three signals: electrocardiogram, phonocardiogram and pulse tracing (carotid pulse). Because of its neglegible pulse transmission time the first derivative impedance cardiogram (dZ/dt) is more reliable than other pulse signals. Since the sharply demarcated points of the dZ/dt waveform occur simultaneously with the cardiac events the dZ/dt makes phonocardiogram processing unnecessary. Computer algorithms for STI assessment are based on processing two signals: the ECG and dZ/dt. The pre-ejection period (PEP), the left ventricular ejection time (LVET) and electromechanical systole (QS2) are derived by recognizing the B and X points on the dZ/dt signal as the endpoints of PEP and LVET respectively. X point identification consists of two steps: (i) the estimation of the QS2 based on the regression relationship between QS2 and heart rate (HR) and (ii) a filtering procedure for exact localization of the X point. The B point is determined by calculating the curvature function of the dZ/dt and employing a clustering procedure. The accuracy and reliability of the software were tested by processing data from 40 subjects under stress condition (cold pressor and mental arithmetic).

Original languageEnglish
Pages (from-to)45-49
Number of pages5
JournalInternational Journal of Psychophysiology
Volume13
Issue number1
DOIs
Publication statusPublished - 1992

Fingerprint

Impedance Cardiography
Systole
Pulse
Electrocardiography
Electric Impedance
Cluster Analysis
Software
Heart Rate

Keywords

  • Computerized measurement
  • Impedance cardiography
  • Systolic time interval
  • Waveform recognition

ASJC Scopus subject areas

  • Behavioral Neuroscience

Cite this

Computer determination of systolic time intervals based on impedance cardiography. / Szilágyi, N.; Láng, Eszter; Balázs, László.

In: International Journal of Psychophysiology, Vol. 13, No. 1, 1992, p. 45-49.

Research output: Contribution to journalArticle

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