The effect of hyperpotassemia on the idioventricular pacemaker in complete A-V heart block and comparison with its effect on the heart rate in normal sinus rhythm: An experimental study in dogs

Data are presented relative to the effects of varying degrees of hyperpotassemia on the atrial and ventricular rates in the presence of normal sinus rhythm and with complete A-V heart block. In the initial or moderately advanced stages of hyperpotassemia with serum levels up to 9.2 mEq./L. there is only a slight change in the atrial and ventricular rates in the presence of normal sinus rhythm. However, in the presence of complete A-V heart block the ventricular rate shows a decrease of 51 per cent (± 3.61 per cent) from the control rate with serum potassium levels up to 7.75 mEq./L. (± 0.22 mEq./L.). The possible relationship between these elevated serum potassium levels and the occurrence of Stokes-Adams seizures in patients with complete A-V heart block is discussed.