Key result
Disopyramide in low potassium causes less depression of action potential amplitude and duration disparity.
Why the study?
The electrophysiological effects of disopyramide phosphate may be altered by low extracellular potassium concentration, potentially affecting its antiarrhythmic efficacy.
Does low extracellular potassium alter the electrophysiological effects of disopyramide phosphate in canine ventricular muscle and Purkinje fibers?
Does low extracellular potassium alter the electrophysiological effects of disopyramide phosphate in canine ventricular muscle and Purkinje fibers?
Low extracellular potassium modifies the electrophysiological actions of disopyramide, suggesting its antiarrhythmic efficacy may be reduced in the presence of hypokalemia.
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Low [K+]o attenuates disopyramide's depression of action potentials in vitro; leaves open clinical relevance in hypokalemia.
Kuś et al. (1978) studied this question. Disopyramide phosphate vs. Normal vs low potassium was evaluated on Electrophysiological actions (action potential amplitude, maximum upstroke velocity, membrane responsiveness, action potential duration, effective refractory period). Disopyramide phosphate had less effect on decreasing the disparity in action potential durations and caused less depression of action potential amplitude in the presence of low potassium.
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