In symptomatic bradycardia, what is the first pharmacologic intervention?

• A. Dopamine
• B. Atropine
• C. Epinephrine
• D. Adenosine

Answer: (B)

In symptomatic bradycardia, the goal is to quickly raise the heart rate by reducing excessive vagal (parasympathetic) influence on the heart. Atropine achieves this by blocking muscarinic receptors, which diminishes the vagal tone on the SA node (and AV node) and allows the intrinsic pacemaker activity to increase the rate. This makes atropine the first pharmacologic intervention to try.

Give a rapid IV bolus of 0.5 mg, and you can repeat every 3–5 minutes to a maximum of 3 mg. If atropine doesn’t improve the situation or if the patient remains unstable or you suspect a high-degree AV block, move promptly to pacing and consider vasopressor support (such as dopamine or epinephrine) as needed. Adenosine isn’t used for bradycardia; it’s reserved for certain tachyarrhythmias and can worsen bradycardia, while dopamine and epinephrine are typically later options when atropine isn’t effective or the patient is unstable.