Advanced Cardiovascular Life Support (ACLS) Practice Exam 2026 – Your Comprehensive All-in-One Guide to Exam Success!

In the context of bradycardia with an unstable patient, beta-blockers are contraindicated. This is primarily because beta-blockers work to decrease heart rate and reduce myocardial oxygen demand by blocking the effects of adrenaline on the beta-adrenergic receptors in the heart. In a patient who is already presenting with bradycardia and instability, administering beta-blockers would further exacerbate the bradycardia and could lead to severe complications, including worsening hypotension and potential cardiovascular collapse.

In contrast, atropine is often used as a first-line treatment for symptomatic bradycardia because it counteracts the vagal influence that slows the heart rate, thereby increasing it. Adrenaline (epinephrine) is also indicated in cases of severe bradycardia as it can stimulate the heart and improve cardiac output. Amiodarone, while primarily an antiarrhythmic, might be used in certain contexts but is generally not the first line for unstable bradycardia. Understanding the pharmacologic actions of these drugs is crucial in the management of bradycardia, particularly in patients who are unstable.