In the case of unstable SVT, what is the treatment method used?

In the case of unstable supraventricular tachycardia (SVT), the appropriate treatment method is synchronized cardioversion. This procedure is used when a patient is experiencing significant symptoms or hemodynamic instability due to rapid heart rhythms. Synchronized cardioversion delivers a controlled electric shock to the heart that is timed to occur during specific phases of the heartbeat, allowing for the restoration of normal rhythm. This is crucial in unstable conditions, as it helps to immediately reestablish an effective cardiac output and mitigate the risk of adverse outcomes.

Other treatment methods, while appropriate in different contexts, are not suitable when there is instability. For example, vagal maneuvers and the administration of adenosine are effective for stable SVT but may not be sufficient for an unstable patient. Cardiopulmonary resuscitation (CPR) is a life-saving intervention but is indicated for cardiac arrest situations rather than specifically for unstable SVT. Thus, synchronized cardioversion stands out as the most effective immediate intervention for unstable SVT.