[Animal experiment study of the design of microelectrodes for selective detection of epicardial potassium ion activities]

Early detection of myocardial ischaemia following cardiac surgery remains a central problem of intensive care medicine. On the basis of the observation in the epicardium that an elevated potassium activity accompanies myocardial ischaemia, a miniaturized electrode system for the measurement of epicardial potassium concentration was constructed and tested. Different types of electrode were implanted in two groups of rabbits. The electrode parameters were satisfactory (slope, screening) and it proved possible to record interference-free myocardial ion potentials, which with regard to the ionophores used is selective for potassium ion activity in the solid phase electrode. The system thus meets the prerequisites for further investigations into its suitability for early diagnosis of ischaemia.