What is the initial treatment for stable narrow-complex tachycardia?

The initial treatment for stable narrow-complex tachycardia typically involves vagal maneuvers or the administration of adenosine. Vagal maneuvers, such as the Valsalva maneuver or carotid massage, can increase vagal tone and help restore a normal heart rhythm by slowing down conduction through the atrioventricular (AV) node. If these maneuvers are not effective, adenosine can be administered. Adenosine works quickly to interrupt reentry pathways in the heart and can effectively terminate certain types of tachyarrhythmias by causing a brief period of asystole.

This approach is especially important because stable narrow-complex tachycardias (like supraventricular tachycardia) can often be terminated without the need for more invasive treatments. Chemical cardioversion usually involves antiarrhythmic drugs and is not the first line of treatment in stable patients, while beta-blockers and amiodarone are typically reserved for situations where vagal maneuvers and adenosine are not successful or in cases of urgent intervention needed for unstable patients.