DIGOXIN TOXICITY COMPARED WITH MYOCARDIAL DIGOXIN AND POTASSIUM CONCENTRATION

<jats:p><jats:list list-type="explicit-label"> <jats:list-item><jats:p>Twenty‐nine dogs were given digoxin (0.25 mg) by mouth twice daily for eight days. Some of them (group 1) also received diuretics and others (group 2) a mineralocorticoid. The dogs were then given an intravenous bolus injection of digoxin and plasma and cardiac muscle were analysed for digoxin and potassium.</jats:p></jats:list-item> <jats:list-item><jats:p>In the digitalized dogs, myocardial potassium concentration decreased following the intravenous injection of either 0.05 or 0.15 mg/kg digoxin; in contrast, in those dogs given diuretics or mineralocorticoid the potassium concentration increased.</jats:p></jats:list-item> <jats:list-item><jats:p>Ventricular arrhythmias occurred after digoxin injection (0.05 mg/kg) in the hypokalemic dogs, in those given a mineralocortocoid and in those dogs which received a toxic digoxin dose (0.15 mg/kg). No arrhythmias where seen in the control (digitalized) group.</jats:p></jats:list-item> <jats:list-item><jats:p>Myocardial digoxin concentrations were similar in the control digitalized group and in the mineralocorticoid‐treated dogs after the intravenous administration of the lower digoxin dose (0.05 mg/kg). The myocardial digoxin concentration was significantly higher in the hypokalemic group and in the group receiving the higher digoxin dose (0.15 mg/kg).</jats:p></jats:list-item> <jats:list-item><jats:p>There was no obvious relationship between the occurrence of arrhythmias and the myocardial concentration of digoxin or potassium.</jats:p></jats:list-item> </jats:list></jats:p>