Which of the following is a characteristic of unstable ventricular tachycardia?

In cases of unstable ventricular tachycardia, one of the defining characteristics is the patient being unresponsive with no cardiac output. Unstable ventricular tachycardia occurs when the heart beats at a rapid rate, preventing it from effectively pumping blood and resulting in reduced or absent cardiac output. This can lead to a significant drop in blood pressure and diminished organ perfusion, often causing the patient to be unresponsive.

Option C highlights the critical nature of this condition, emphasizing the urgency of intervention, such as defibrillation, to restore a stable heart rhythm and improve cardiac output. Recognizing these signs is essential for prompt treatment, as the longer a patient remains in this state, the more severe the consequences can become.