[Continuous noninvasive measurements of cardiac output during exercise by impedance cardiography--application to evaluation of cardiac output kinetics].
The purpose of the present study was to compare the impedance derivate waveforms using spot and band electrode array and to assess applicability of automated signal processing system for cardiac output kinetics. Five healthy male subjects were tested. Cardiac output (Q) were measured using spot electrode array. Each subject performed rest-exercise transitions in leg and arm exercise on an electrically braked ergometer. The intensities of leg exercise were 25, 50, and 100 W for 5 min and those of arm exercise were 25 and 50 W. Comparisons between spot and band electrodes were made for the absolute magnitude of Q and stroke volume (SV), as well as for impedance derivative waveforms. The waveforms for spot electrodes showed less fluctuation by breathing and movement artifacts than for band electrodes. Q for spot electrodes were larger than those for band electrodes. There was a significant correlationship between oxygen uptake (Vo2) and Q. There was a significant correlationship between Q using spot electrode and Q measured by CO2 rebreathing method. Nonlinear correlation coefficient to exponential curve of Q kinetics for leg exercise was more than 0.7 and for arm exercise more than 0.4 in spite of large movement of upper body. It is suggested that the present system using spot electrodes is superior in signal processing to those for band electrodes and able to evaluate Q kinetics without multiple repetition of exercise tests.
Shiojiri
T
T
Division of Education, Graduate School, Kobe University.
Shimana
T
T
Koga
S
S
Kondo
N
N
Iwata
A
A
D000328:Adult; D002302:Cardiac Output / Q000502:physiology*; D002307:Cardiography, Impedance; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D007700:Kinetics; D008297:Male; D012815:Signal Processing, Computer-Assisted