Potassium Infusion for Conversion of Atrial Fibrillation/-Flutter

Atrial fibrillation is a condition in which the heart's upper chambers, the atria, contract at an abnormally rapid rate. It is a common type of arrhythmia, and occurs in 1-2% of the general population. The prevalence of atrial fibrillation increases with age. Between 50 and 70% of patients with atrial fibrillation lasting <48 hours spontaneously convert to normal sinus rhythm, and drug therapy increases the likelihood of conversion to sinus rhythm. Another treatment option for conversion of atrial fibrillation and atrial flutter is electrical conversion. This is an effective treatment but requires anesthesia. Current treatment strategy for medical conversion of atrial fibrillation and atrial flutter is to employ drugs that affect ion channel activity in atrial cardiomyocytes. However, such converting drugs all have potentially serious side effects and are expensive. Potassium, sodium, calcium, and magnesium molecules are the most important ions causing electric current in the heart tissue. Our hypothesis is that hypokalemia promotes atrial fibrillation/atrial flutter by a direct effect on cardiomyocytes. Accordingly, we also hypothesize that potassium infusion may convert atrial fibrillation/atrial flutter to normal sinus rhythm. If so, this would be an inexpensive treatment with potentially very few side effects.

Potassium chloride infusion at a rate of 15 mmol/h (60 mmol KCl in 1000 ml of 5% glucose with a concentration of 0.05 mmol/mL, flow rate 265 mL/h). If the serum Mg ≤0.8 mmol/L, MgSO4 infusion (0.5 mmol/kg/24 hours in 1000 mL NaCl 0.9% corresponding to an infusion rate of approximately 42 mL/hour) will also be administered.

The patients will be followed up with a resting ECG about three months after study intervention, and subsequently on-demand ECG will be monitored for 72 hours.

Inclusion Criteria: Patients with paroxysmal atrial fibrillation/atrial flutter with duration <48 hours Plasma potassium ≤4,0 mmol/L. Age ≥ 18 år Exclusion Criteria: Plasma potassium > 4,0 mmol/L eGFR <30 mL/min Patients on antiarrhythmic therapy (flecainid, amiodarone, dronedarone or sotalol) Pregnancy Breast feeding Patients participating in a clinical trial during the last six months Addison disease, adynamia episodic hereditary, or Sickle cell anemia Metabolic acidosis, pH < 7,2

Tazmini K, Fraz MSA, Nymo SH, Stokke MK, Louch WE, Oie E. Potassium infusion increases the likelihood of conversion of recent-onset atrial fibrillation-A single-blinded, randomized clinical trial. Am Heart J. 2020 Mar;221:114-124. doi: 10.1016/j.ahj.2019.12.014. Epub 2019 Dec 27.