Korean J Aerosp Environ Med.  2001 Dec;11(4):208-214.

The Cardiac Output and the Cardiac Muscle Contractility During Postural Gradient Changes by Tilt Table in Man

• Ko SK

Abstract

The purpose of this study is to investigate changes of the cardiac output and the cardiac muscle contractility during postural gradient changes in man. Subjects consisted of 15 healthy males that they were aged 23-24 years. The Cardiac output and the contractility were calculated using the impedance cardiogram that were recorded by new apparatus developed in Yonsei Medical Center. The impedance cardiogram was recorded in different 7 gradients which were 0degrees, +/-2degrees, +/- 45degrees and +/-90degrees according to the head position, but it was continuously recorded at each gradient. The each postural gradient was changed after supine resting, 15-20 min, and continued in 5 min. Results of this study were following, 1. The cardiac output was decreased at head up posture (+2degrees, +45degrees and +90degrees) because of decreasing stroke volume. But the cardiac output was increased at head down posture (-2degrees, -45degrees and -90degrees) by increasing stroke volume. 2. The cardiac output was significantly changed at +/-45degrees and +/-90degrees after immediately gradient changes, but it was no significant difference at 0 and +/-2degrees postures from that of supine resting state. 3. At +/-45degrees and +/-90degrees, the cardiac muscle contractility was increased, and in head up posture, amounts of change were more larger than in head down posture.

Keyword

Cardiac output; Cardiac muscle contractility; Impedance cardiography

MeSH Terms

Cardiac Output*
Cardiography, Impedance
Electric Impedance
Head
Humans
Male
Myocardium*
Posture
Stroke Volume