Ambulatory monitoring of the impedance cardiogram.
The growing need for more advanced ambulatory monitoring has led to the development of an ambulatory monitor for impedance cardiography (VU-AMD). This paper presents two studies addressing the validity of the VU-AMD. In the first study, the cardiovascular responses of 25 subjects during various conditions were simultaneously recorded with the VU-AMD and a standard laboratory impedance device. Correlations between the responses of the ambulatory and laboratory devices were high, both inter- and intraindividually, except for stroke volume and cardiac output during exercise. In the second study, 26 subjects underwent 24-hr monitoring with the VU-AMD. The values obtained with the VU-AMD were realistic and varied in a predictable way over activity and posture. It is concluded that the VU-AMD is a valid device for the measurement of systolic time intervals in real-life situations, but its applicability for absolute stroke volume and cardiac output determination remains to be established.
Willemsen
G H
GH
Department of Psychonomy, Vrije Universiteit, Amsterdam, Netherlands.
De Geus
E J
EJ
Klaver
C H
CH
Van Doornen
L J
LJ
Carroll
D
D
D000328:Adult; D002307:Cardiography, Impedance / Q000295:instrumentation / Q000379:methods*; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male