The nurse understands that which of the following medications is a potassium channel blocker?

A. Radiofrequency ablation: This is used to treat tachyarrhythmias such as atrial fibrillation, atrial flutter, or supraventricular tachycardia (SVT). The ECG shown does not demonstrate any tachycardic rhythm rather, it shows a bradyarrhythmia with dropped QRS complexes, which suggests a conduction block, not a reentrant circuit.

B. Administration of amiodarone: Amiodarone is primarily used for ventricular arrhythmias or atrial fibrillation. It is not effective in treating bradyarrhythmias or heart blocks such as those seen in this rhythm strip.

C. Insertion of a pacemaker: The rhythm strip shows intermittent dropped QRS complexes with consistent P waves—this is indicative of second-degree AV block, Mobitz II. This type of conduction block can progress to complete heart block and is often treated with the insertion of a permanent pacemaker to maintain cardiac output.

D. Administration of adenosine: Adenosine is used to terminate SVT by temporarily blocking AV node conduction. It is contraindicated in heart blocks, especially Mobitz II or third-degree AV block, because it can worsen the block and cause asystole.

A. Administer amiodarone IV push followed by a continuous infusion: Amiodarone is part of the Advanced Cardiac Life Support (ACLS) algorithm for ventricular fibrillation (VF) or pulseless ventricular tachycardia, but it should only be given after confirming the rhythm and initiating basic life support steps, including pulse check.

B. Establish unresponsiveness and check the carotid pulse: The rhythm strip shows ventricular fibrillation, a life-threatening arrhythmia. However, before initiating advanced interventions such as defibrillation, the nurse must first confirm the client is unresponsive and pulseless, which is the correct initial action according to ACLS protocols.

C. Immediately defibrillate the client using the synchronous mode: Defibrillation is the correct treatment for VF, but it must be done in unsynchronized mode. Additionally, it is not appropriate to defibrillate until pulselessness is confirmed. Synchronized mode is used for rhythms like unstable SVT or atrial fibrillation not VF.

D. Initiate a rapid response call and increase the monitor’s sensitivity: A rapid response team is called for deteriorating patients who are still responsive. If the client is unresponsive and pulseless, a code blue or cardiac arrest protocol should be initiated, not just a rapid response. Monitor sensitivity adjustments are irrelevant in a confirmed life-threatening rhythm.