Hyperkalemia is a common electrolyte abnormality frequently complicated with chronic kidney disease. By injecting potassium chloride (KCl) solutions intravenously into bullfrogs, we reproduced typical electrocardiogram (ECG) abnormalities of hyperkalemia in the frog hearts, such as the peaked T waves and the widening of QRS complexes. Simultaneous recordings of cardiac action potentials showed morphological changes that synchronized with those of ECG. After 100 mM KCl injection, the widened QRS complexes continued for a while and gradually restored to their baseline widths. However, pre-treatment with sodium bicarbonate or salbutamol, which directly or indirectly stimulates Na+/K+-ATPase activity, significantly facilitated the recovery from the widened QRS duration, indicating the transcellular movement of potassium ions from the extracellular fluid into the intracellular stores.
Keywords: bullfrog heart; electrocardiogram (ECG); hyperkalemia; salbutamol; sodium bicarbonate.