Mechanism of Cardiac Changes Observed in Uremia.

Abstract

In the uremic state an increase in level of serum K and a sequential pattern of cardiac changes similar to those observed by vagal stimulation or by experimentally increasing levels of serum K may be seen. Since increased K concentration either of the heart or serum does not account for all the cardiac changes, the cholinesterase activity of hearts for uremic dogs was estimated. Studies were made on 6 normal dogs and 8 uremic dogs. Cholinesterase activity was determined according to the method of Ammon. The microliters of CO2 evolved/hour/mg dry weight of homogenate was 4.4 (range 3.5-5.6) for normal dogs, and for uremic dogs the average was 2.8 (range 2.1-3.3). The observed ecg changes, characteristic of an impedance or block in action potential propagation in the heart, may therefore be specifically related to changes in the acetylcholinesterase activity of the conductive elements of this organ.