Hyperkalemia probably reverses the antiarrhythmic effects of amiodarone: a case report

Electrocardiographic changes in the acute hyperkalaemia produced by intragastric KCl load in rats

NEW FINDINGS

What is the central question of this study? This study presents a new model for studying the rapid onset of severe, acute hyperkalaemia in rats with intact kidney function by administering an intragastric KCl load. What is the main finding and its importance? This new model of intragastric KCl load produces a reliable and reproducible model for studying the rapid onset of severe, acute hyperkalaemia in rats with intact kidney function. We report unprecedented rapid changes (30 min) in ECG, blood pressure and various arterial blood analyses with this new model, providing a solid foundation for future experiments in this field.

ABSTRACT

A variety of animal models have been proposed to study hyperkalaemia, but most of them have meaningful limitations when the goal is to study the effect of potassium overload on healthy kidneys. In this study, we aimed to introduce a new approach for induction of hyperkalaemia in a reliable and reproducible animal model. We used intragastric administration of potassium chloride [KCl 2.3 M, 10 ml/(kg body weight)] to male Holtzman rats (300-350 g) to induce hyperkalaemia. The results showed that this potassium load can temporarily overwhelm the renal and extrarenal handling of this ion, causing an acute and severe hyperkalaemia that can be useful to study the effect of potassium imbalance in a variety of scenarios. Severe hyperkalaemia (>8 meqiv/l) and very profound ECG alterations, characterized by lengthening waves and intervals, were seen as early as 30 min after intragastric administration of KCl in rats. In addition, a transient increase in arterial blood pressure and time-dependent bradycardia were also seen after the KCl administration. No metabolic acidosis was present in the animals, and the potassium ion did not increase proportionally to chloride ion in the blood, leading to an increased anion gap. In conclusion, the results suggest that intragastric KCl loading is a reliable model to promote rapid and severe hyperkalaemia that can be used for further research on this topic.

Resuscitation from Transfusion-Associated Hyperkalaemic Ventricular Fibrillation

Evidence to guide resuscitation from transfusion-related hyperkalaemic ventricular fibrillation is sparse. This case report describes a 29 kg patient undergoing scoliosis surgery who developed hyperkalaemic ventricular tachycardia/fibrillation following the replacement of over two blood volumes with banked blood in 90 minutes. Rapid reversion to sinus rhythm followed administration of 1.4 mmol of calcium chloride and two units of insulin (Actrapid, Novo Nordisk). The relevant literature is reviewed, indicating that an elevated serum ionised calcium level protects against hyperkalaemia, by an intracellular mechanism. Evidence supports the use of lignocaine, but not amiodarone, as additional treatment.

Recurrent supraventricular tachycardia in a newborn treated with amiodarone: is hyperkalemia the apparent cause?

Supraventricular tachycardia (SVT) is the most common type of arrhythmia observed in children, especially in newborns. Infants with severe SVT must be treated immediately with first-line drugs such as amiodarone. There are some minor and major side effects of amiodarone in this patient group, but no associated electrolyte disorders have been observed. This report describes a newborn whose recurrent SVT attacks during amiodarone treatment were suspected to have been caused by hyperkalemia.

Torsade de pointes with a normal QT interval associated with hypokalemia: a case report

The patient was a 46-year-old man with a history of syncope attack after diarrhea. Nonsustained polymorphic ventricular tachycardia (PVT) initiated by short-coupled premature ventricular complex was detected by Holter monitoring. No organic heart disease was found, and the QT interval during sinus rhythm was normal. It was thought that the PVT might be related to hypokalemia, so electrophysiological studies were performed under the condition of hypokalemia (K=3.4mmol/L), after potassium loading (K=4.2mmol/L) and after oral amiodarone therapy. Under the condition of hypokalemia, nonsustained PVT occurred spontaneously, and the monophasic action potential duration at 90% repolarization (MAPD90) at the right ventricular apex was very short (175 ms). The MAPD90 returned to normal after loading potassium (230ms) and after oral amiodarone therapy (240ms), and PVT no longer occurred. With continued oral amiodarone and spironolactone therapy, the patient has been free of syncope attack over a follow-up period of 5 years.