[Passive electric studies on the normal and atherosclerotic human aorta at ultra-low frequencies]

The passive electrical behaviour of the normal and the atherosclerotic human aorta was investigated at very low frequencies between 0.4 and 0.002 Hz. In the normal as well as in the pathologically changed vessel wall the upper part of an additional dispersion area below the region of alpha-dispersion was found. Furthermore all values of the dielectric constant in atheromatous plaques were situated above the values of the normal aorta. There is every indication that also at very low frequencies the dispersion behaviour of the atheromatous plaques is determined by larger structures than in the normal aorta. The further extension of the measurements to even lower frequencies and theraby the registration of the total dispersion area is limited by the inconstancy of the measuring object during a period (about 15 min).