Transcutaneous electrohepatogram in humans

We could recently characterize a normal "electrohepatogram" (EHG) in a canine model. It consisted of monophasic positively deflected slow waves or pacesetter potentials (PPs). A "dysrhythmic EHG" was produced when the liver was insulted by hepatic vessel clamping or liver irradiation. The postulation that electrohepatography might act as an investigative tool in liver diseases prompted the author to develop the EHG percutaneously in humans. 23 healthy volunteers (16 men, 7 women; mean age 38.6 years) and 13 patients (8 men, 5 women; mean age 34.2 years) with huge supraumbilical ventral hernia were studied. The liver was exposed during the ventral hernia repair and 3 electrodes were sutured to the liver capsule. The optimal position for percutaneous recording was identified. The 3 electrodes were placed, 5 cm apart, on a transverse line, parallel to and 1.5-2 cm below, the costal margin. PPs were recorded from the 3 electrodes applied directly to the liver and from those applied to the skin. The wave was monophasic and positively deflected with a mean frequency of 8.3 cycle/s and amplitude of 56.5 microV. The PPs had the same frequency and amplitude from the 3 electrodes applied to the same subject. The percutaneously recorded waves were identical with those recorded directly from the liver. A percutaneous EHG could be characterized for the normal liver in humans. It might show changes in liver diseases and thus act as an investigative tool in the diagnosis of such conditions.