title: Studies on separating the impedance change components of blood vessels and ventricles in thorax from mixed impedance signals on chest surface.
abstract: OBJECTIVE
  The aim of the present study is to separate the impedance change components of the blood vessels and ventricles in thorax from the mixed impedance signals detected on the chest surface.
  
  
  METHODS
  The mixed impedance signals on the chest surface are measured with a 15 electrode lead system. The thoracic impedance equations are established and solved iteratively with the algebraic reconstructed technique. Experiments were performed on 80 healthy, otherwise normal, adults.
  
  
  RESULTS
  Five impedance change components for the aorta (AO), blood vessel in left lung (PL), blood vessel in right lung (PR), left ventricle (LV), and right ventricle (RV) are separated from the mixed impedance signals. The experiments show that the main waveform of the ventricular components LV and RV is contrary to that of the vascular components AO, PL, and PR, and the negative peak point of the waveform graphs of LV and RV are in phase with the second cardiac sound (S2). The waveform graphs of various components correspond with the physiological activities of the heart and blood vessels in a cardiac cycle. The statistical results for 80 normal adults show that the amplitude of AO is the largest and that of PL and PR is the next, while that of LV and RV is the smallest. There are significant differences between them (P < 0.01).
  
  
  CONCLUSIONS
  The mathematical model and the measurement method for the separation in the present paper are feasible.
authors.affiliation: Department of Basic Medicine, Medical College of Nanchang University, Jiangxi Nanchang 330006, China.
authors.forename: Ming-Xing
authors.initials: MX
authors.lastname: Kuang
authors.forename: Qiu-Jin
authors.initials: QJ
authors.lastname: Xiao
authors.forename: Nan-Zhen
authors.initials: NZ
authors.lastname: Kuang
authors.forename: Chao-Ying
authors.initials: CY
authors.lastname: Cui
authors.forename: Ai-Rong
authors.initials: AR
authors.lastname: Hu
mesh_terms: D000328:Adult; D001808:Blood Vessels; D017097:Electric Impedance; D005260:Female; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D012815:Signal Processing, Computer-Assisted; D013909:Thorax; D055815:Young Adult