Final answer:
The priority intervention for the nurse when a client's rhythm converts to supraventricular tachycardia (SVT) after ventricular fibrillation (VF) is to assess the client's vital signs and administer appropriate medication if necessary.
Step-by-step explanation:
When a client's rhythm converts to supraventricular tachycardia (SVT) after ventricular fibrillation (VF), the priority intervention for the nurse is to assess the client's vital signs, including heart rate and blood pressure, and to administer appropriate medication if necessary. SVT is a rapid heart rhythm that originates above the ventricles, and it can cause symptoms such as palpitations, dizziness, and shortness of breath. Medications like adenosine or beta blockers can be used to slow down the heart rate and restore a normal sinus rhythm.