Abstract
The effects of potassium chloride on inotropic and chronotropic activity were investigated in five isolated canine atrium preparations which were suspended in a bath and perfused with arterial blood from the carotid artery of the heparinized support dog. Potassium chloride administered into the cannulated sinus node artery in a dose range of 100 μg-1 mg produced a dose-related negative inotropic and a positive chronotropic effect. These effects were not influenced by treatment with either atropine or propranolol. From these results, it is concluded that potassium has a direct negative effect on atrial contractility and a direct positive effect on atrial rate.
