Changes in the impedance cardiogram occurring with change in posture in patients with heart disease.

The response of the heart to changes in posture from supine through sitting to standing was recorded by impedance cardiography. The study comprised 22 normal subjects and 74 patients with a variety of heart diseases. The results demonstrate that in normal subjects acceleration of blood in systole decreased on sitting and standing. In subjects with impaired cardiac function this acceleration increased on sitting and standing from the supine position. This clear-cut difference in response provides a subtle method of detecting impaired function and in addition, provides a method of monitoring the effects of vasodilator or other treatment.