Key result
Moderate extracellular potassium elevation drives transient positive inotropy followed by a negative inotropic effect.
Elevated extracellular potassium exerts both positive and negative inotropic effects on mammalian ventricular muscle, with the positive effect occurring independently of action potential changes.
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Should not alter clinical potassium management; leaves open direct inotropic mechanisms in human myocardium.
Kavaler et al. (1972) studied Cat ventricular muscle (experimental) (n=22). Moderate elevation in extracellular potassium concentration was evaluated on Isometric force development (contraction). Moderate elevation in extracellular potassium concentration produced a transient positive inotropic effect independent of action potential changes, followed by a negative inotropic effect.
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