As the population ages, the rate of AF is increasing, as shown by data from the CDC, which found that between 2006 to 2014, the primary AF event rate (i.e., primary diagnosis/underlying cause of death) increased 8% from 249 to 268 per 100,000, while the comorbid AF event rate (i.e., secondary diagnosis/contributing cause of death) increased 25% from 1,473 to 1,835 per 100,000, respectively.

Treatment modalities include pharmacotherapy and electrical conversion, but due to the frequent recurrence rate and rates of spontaneous conversion, neither strategy is without risk nor are they cost-effective. Electrolyte imbalances involving potassium and magnesium may play a role in AF and atrial flutter (AFl); however, data are limited.

To help clarify the role of potassium and magnesium administration in AF and AFl, investigators analyzed data on the combined IV administration of potassium and magnesium for the probably of spontaneous conversion to sinus rhythm (SCV) among patients who were treated in an academic emergency department (ED) in Vienna, Austria.

Observational data were analyzed from an arrhythmia registry–based cohort study of patients admitted with either AF or AFl. All consecutive patients aged 18 years or older with supraventricular tachycardia confirmed by a 12-lead electrocardiogram who were treated in the ED between February 6, 2009, and February 16, 2020, and who did not have permanent AF or AFl were included in the study.

Guidelines do not provide recommendations for or against electrolyte administration in AF or AFl. The normal range for plasma potassium levels was 3.5 mEq/L to 5.1 mEq/L, and the normal range for plasma magnesium levels was 1.6 mg/dL to 2.6 mg/dL. They administered a premade electrolyte infusion that consisted of potassium 24 mEq and magnesium 145.8 mg per 250 mL. This was usually given with 500 mL of balanced crystalloid fluid that contained 2.5 mEq of potassium and 18.2 mg of magnesium run over 90 minutes. The infusion rate could be reduced depending on tolerability.

SCV was defined as return to spontaneous sinus rhythm without the use of pharmacologic rhythm control (i.e., the use of ibutilide, vernakalant [not available in the United States], sotalol, flecainide, propafenone, or amiodarone) regardless of dose administered. Use of beta-blockers, nondihydropyridine calcium channel blockers, or digitalis glycosides for rate control or the use of electrical cardioversion (if unsuccessful) were allowed and considered SCV. These long-term antiarrhythmics were allowed because they were deemed to not have a substantial effect on SCV.

During the study period, a total of 3,119 episodes of AF (81.6%) or AFl (18.4%) were analyzed. The median age was 68 years in both groups, and males made up more than one-half of the study population. The median duration of stay in the ED was 6.4 hours for AF patients and 6.1 hours for AFl patients.

Of these 3,119 episodes, the IV potassium/magnesium infusion was administered in 56.5% (1,763 patients). SCV occurred in 15.4% of AF episodes and 12.7% of AFl episodes. In the former group, IV potassium/magnesium almost doubled the odds of SCV (odds ratio [OR] 1.98; 95% CI, 1.53-2.57) compared with no administration. Patients with a baseline potassium level of <3.5 mEq/L and 3.50 mEq/L to 3.99 mEq/L based on stratification had significantly higher odds of SCV in AF episodes compared with those with a potassium level of 4.0 mEq/L to 4.49 mEq/L or >4.5 mEq/L.

A similar correlation was not seen with magnesium levels as effect size estimates were largely constant. If AF symptoms had been present for 48 hours or more, the electrolyte infusion had no effect on SCV. IV potassium/magnesium also had no effect on the chances of SCV in patients with AFl (OR 1.05; 95% CI, 0.65-1.69). Baseline potassium and magnesium levels did not affect AFl outcome nor did symptom onset. When the outcome for the whole cohort (AF and AFl patients) was assessed, there was a significant between group difference for overall SCV rates for AF and AFl associated with the use of the IV potassium/magnesium infusion (P = .02).

Although preliminary, this study provides pharmacists with encouraging information that the administration of IV potassium and magnesium may lessen the need for antiarrhythmics and their potential adverse events in those with nonpermanent AF.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

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