Does acidosis or hyperkalemia affect the effectiveness of sympathomimetic amines in increasing idioventricular rate in dogs with complete A-V heart block?
Acidosis, but not hyperkalemia, reduces the chronotropic efficacy of sympathomimetic amines in a canine model of complete A-V block.
Acidosis was found to diminish the effectiveness of various sympathomimetic amines (isoproterenol, norepinephrine, and epinephrine) in increasing the idioventricular rate in dogs with experimentally induced complete A-V heart block. This diminution was correlated with the degree of acidosis (metabolic and respiratory). Hyperkalemia without significant pH change had no such effect.
Guzmán et al. (Wed,) studied this question.