In which scenario is Adenosine most effective?

Adenosine is most effective in terminating episodes of narrow-complex paroxysmal supraventricular tachycardia (PSVT). This type of arrhythmia is characterized by a rapid heart rate due to reentry pathways, which usually involves the atrioventricular (AV) node. Adenosine works by temporarily blocking conduction through the AV node, interrupting the reentrant circuit, and allowing for a normal sinus rhythm to be restored.

Its rapid onset of action and short half-life make adenosine particularly useful in clinical scenarios involving narrow-complex tachycardias, as it can quickly revert the heart rate back to normal. The safety profile of adenosine, with few serious side effects and the ability to quickly evaluate the effect, supports its use specifically for this condition.

In other scenarios listed, such as asystole or stable V-tach, adenosine would not be effective. Asystole, which is a lack of electrical activity in the heart, requires different interventions such as chest compressions and advanced cardiac life support (ACLS) protocols, not the administration of adenosine. Similarly, stable V-tach may require other interventions such as antiarrhythmic medications or electrical cardi