What is the optimal treatment for a patient presenting with regular narrow-complex tachycardia and hypotension?

The optimal treatment for a patient presenting with regular narrow-complex tachycardia and hypotension is intravenous adenosine. In the context of a tachycardia, adenosine acts as a rapid-acting antiarrhythmic medication that can effectively terminate supraventricular tachycardias (SVT).

When a patient exhibits hypotension associated with regular narrow-complex tachycardia, it typically indicates a hemodynamically unstable rhythm, necessitating immediate intervention to restore normal heart rhythm and improve blood flow. Adenosine works quickly, allowing for immediate assessment of the underlying rhythm changes. If the tachycardia is due to a reentrant circuit (as found in many SVTs), adenosine can restore a normal sinus rhythm by interrupting the conduction pathway.

Other medications, such as oral beta-blockers, take longer to exert their effects and are not suitable for acute treatment in a hypotensive patient. Cardioversion is appropriate in cases of severe instability; however, adenosine is typically the first-line treatment for regular narrow-complex tachycardias. Aspirin is more relevant for anti-platelet therapy and does not address the acute arrhythmia or hypotension in this context.