THE INHIBITION OF ACETYLCHOLINE-INDUCED ATRIOVENTRICULAR BLOCK BY POTASSIUM*

Abstract

The exact relationship of potassium and digi- talis is still an unsettled question despite intensive study by numerous investigators. There is evi- dence to indicate that in subjects with atrial fibril- lation treated with digitalis, intravenous potas- sium results either in "improvement" of atrioven- tricular (AV) conduction, or in progression of the AV block (1-3). The possibility has been entertained that this paradoxical response to potas- sium depends on whether the digitalis-induced AV block is due to the vagal or to the direct effect of the glycoside on the conduction tissue (4).