Compared with no treatment, potassium and magnesium administration was associated with a 10% higher rate of SVC.
The finding suggests that giving intravenous potassium and magnesium might lessen the need for antiarrhythmic therapy and the associated potential adverse effects in patients with nonpermanent atrial fibrillation (AFib), the study authors say.
Still, they add, “The results of our study have no direct implications for clinical practice in the management of care for patients with AF [atrial fibrillation] or AFL [atrial flutter] in the ED. The findings are purely exploratory and hypothesis-generating but could potentially provide a rationale for an appropriate prospective trial.”
The study was published online in JAMA Network Open.
“Atrial fibrillation is becoming an increasing burden for health care systems worldwide owing to population aging,” write Filippo Cacioppo, MD, and colleagues from Medical University of Vienna (Austria).
“Pharmacologic and electrical conversion are common therapies in emergency departments, especially for highly symptomatic patients. Each intervention has specific risks, and neither is considered cost-effective owing to frequent recurrence of AF. In addition, AF often terminates spontaneously,” Dr. Cacioppo and colleagues write.
They add that evidence suggests hypokalemia and hypomagnesemia contribute to AFib development, and so the administration of potassium and magnesium could be a reasonable strategy to improve SCV rates.
To test their hypothesis, Dr. Cacioppo and associates conducted a registry-based cohort study in all patients with AFib or AFL presenting to their center’s ED between Feb. 6, 2009, and Feb. 16, 2020.
During this time, they observed a total of 2,546 episodes of nonpermanent AFib. The median patient age was 68 years (interquartile range, 58-75 years). Most were men (n = 1,411 patients, 55.4%).
In addition, there were 573 episodes of nonpermanent AFL. The median patient age was 68 years (IQR, 58-75 years), and 332 patients (57.9%) were men.
Intravenous potassium and magnesium were administered in just over half (n = 1,763; 56.5%) of the episodes.
The median amount of potassium and magnesium was delivered via one 250-mL infusion bag, which consisted of 24 mEq potassium and 145.8 mg magnesium combined with 500 mL of balanced crystalloid fluid containing 2.5 mEq potassium and 18.2 mg magnesium, administered for 90 minutes, the authors write.
If patients experienced pain at the injection site, the infusion rate was reduced until the pain subsided.
Conversion to sinus rhythm was considered spontaneous if no attempt at pharmacologic rhythm control was made until conversion occurred; if SCV occurred after an unsuccessful attempt at electrical cardioversion; or following rate control with beta-blockers, nondihydropyridine calcium channel blockers, or digitalis glycosides, the authors state.
IV treatment increased odds of SCV
The median duration of stay in the ED was 6.4 hours (IQR, 3.9-11.6 hours) for patients with AFib and 6.1 hours (IQR, 3.9-11.8 hours) for patients with AFL.
During the stay in the ED, SCV occurred in 15.4% (n = 393) of AFib episodes and 12.7% (n = 73) of AFL episodes.
Intravenous potassium and magnesium increased the possibility of SCV compared with no IV potassium and magnesium in AFib, but not in AFL.
In episodes of AFib, administration of intravenous potassium and magnesium was associated with 19.2% increased odds of SCV, compared with 10.4% with no administration (odds ratio, 1.98; 95% CI, 1.53-2.57).
In contrast, for AFL, no association was observed for the probability of SCV with potassium and magnesium administration when compared with no administration (13.0% vs. 12.5%; OR, 1.05; 95% CI, 0.65-1.69).