What is the recommended immediate management for a patient with a hemodynamically unstable tachyarrhythmia?

• A. Defibrillation
• B. Vagal maneuvers
• C. Synchronized electrical cardioversion
• D. Adenosine administration

Answer: (C)

When a tachyarrhythmia causes hemodynamic instability, the priority is rapid rhythm control with a synchronized electrical shock to restore perfusion. Synchronized cardioversion delivers energy timed to the heart’s R wave, which minimizes the risk of inducing ventricular fibrillation and quickly converts the rhythm toward a stable rate.

Defibrillation is reserved for pulseless arrest, not an unstable patient with a pulse. Noninvasive maneuvers like vagal techniques or adenosine rely on the patient being stable and often take time, which is not acceptable when perfusion is compromised. Adenosine, in particular, can be unsafe or ineffective in unstable patients and may worsen hemodynamics.

So the best immediate step is synchronized electrical cardioversion to rapidly reestablish a stable rhythm and improve circulation.