When Afib presents acutely, which lab value should be checked, along with what is the initial treatment?

When atrial fibrillation (AFib) presents acutely, it is critical to evaluate the underlying causes, which can include electrolyte imbalances and thyroid dysfunction. Checking the thyroid-stimulating hormone (TSH) is particularly relevant because hyperthyroidism is a common reversible cause of AFib, especially in older adults.

In terms of initial treatment, beta blockers are often used to control the heart rate in patients with acute AFib. They can help reduce the rapid heart rate and improve symptoms, making them an appropriate choice. Thus, determining TSH levels and initiating therapy with beta blockers addresses both the potential underlying etiology and the immediate need for heart rate control effectively.

Other options listed may identify important conditions or suggest appropriate treatments; however, they do not provide the most relevant first steps in managing acute AFib. Potassium levels could indeed play a role if there is suspicion of an electrolyte disturbance, but digoxin is less commonly the first-line treatment for acute rate control compared to beta blockers. A coagulation profile is relevant for assessing stroke risk and management but does not address the immediate rate control nor the etiological reasons behind the AFib episode itself, while checking a complete blood count (CBC) may not directly relate to the acute management of