Effect of Potassium Infusion on the Human Conduction System

Abstract

His bundle electrograms were recorded in 12 patients before and after the intravenous administration of 5 mEq of potassium. Antegrade and retrograde refractory periods were determined with the extrastimulus technique. The AH interval was 84 ± 7 msec before and 89 ± 7 msec after potassium ( P < 0.05). The AH interval at an atrial pacing rate of 140/minute was 129 ± 13 msec be fore and 143 ± 16 msec after potassium ( P < 0.02). The effective refractory pe riod of the atrium was 264 ± 9 msec before and 280 ± 9 msec after potassium ( P < 0.001). Thus small amounts of potassium delay conduction at the atrial and AV nodal level.