Which medication is used for life-threatening arrhythmias and targets cardiac tissue?

• A. Adenosine
• B. Active Transport
• C. Absorption
• D. Pharmacodynamics

Answer: (A)

Adenosine works because it acts directly on heart tissue to interrupt the pathway that drives many supraventricular tachycardias. By activating A1 receptors in the atrioventricular (AV) node, it briefly enhances potassium efflux and hyperpolarizes nodal cells, causing a transient AV nodal block. This short interruption of conduction can terminate a reentrant circuit and stop the tachycardia, restoring normal rhythm. Its effect is extremely rapid and short-lived, which is ideal for acute emergency situations and is why it’s given as a rapid IV bolus with a saline flush. The other options aren’t medications that target cardiac tissue for arrhythmia management; they describe processes or pharmacology concepts rather than an actual drug used to treat life-threatening arrhythmias.