What is considered the first step in the stepwise management of supraventricular tachycardia?

The first step in the stepwise management of supraventricular tachycardia (SVT) is to attempt vagal maneuvers, such as carotid massage. This approach targets the autonomic nervous system to increase vagal tone, which may help to terminate the tachycardia by slowing down conduction through the atrioventricular (AV) node. Vagal maneuvers are typically safe and can be performed quickly in a clinical setting, making them a logical first choice.

If carotid massage is not effective, intravenous adenosine can be administered as it works quickly to block conduction through the AV node and can also help terminate SVT. In cases where the patient is hemodynamically unstable, immediate cardioversion is the preferred approach over vagal maneuvers or medication.

Electrophysiological studies, while informative for assessing the underlying causes of SVT, are usually not considered a first-line management option but rather part of the longer-term evaluation and treatment strategy. Thus, performing vagal maneuvers as the initial management is the most appropriate and commonly accepted practice in acute settings.