Final answer:
For a patient with a rapidly deteriorating condition due to persistent tachyarrhythmia, the best intervention is to perform synchronized cardioversion, which can promptly restore a stable heart rhythm.
Therefore the correct answer is option B) Perform synchronized cardioversion
Step-by-step explanation:
The most appropriate intervention for a rapidly deteriorating patient with persistent tachyarrhythmia on lead II ECG is B) Perform synchronized cardioversion. This treatment involves the delivery of a therapeutic dose of electrical energy to the heart at a specific moment in the cardiac cycle, which is synchronized with the R wave of the ECG.
While other treatments such as antiarrhythmic medications like amiodarone or therapeutic hypothermia might be relevant in different contexts, in the emergency setting of a patient with tachyarrhythmia, where the condition is life-threatening, immediate cardioversion is typically the most effective option to restore a stable heart rhythm.