Patient Care Technician (PCT) AAH Practice Exam

Which rhythm is characterized by a ventricular rate of more than 100 beats/min from the AV bundle?

1. Ventricular fibrillation

2. Junctional Tachycardia

3. Accelerated Junctional Rhythm

4. Sinus tachycardia

The correct answer is: Junctional Tachycardia

Junctional tachycardia is characterized by a ventricular rate exceeding 100 beats per minute originating from the AV junction. This occurs when the usual pacemaking activity of the sinus node is disrupted, leading the AV junction to take over as the main pacemaker. The junctional tissue maintains the rhythm, usually resulting in a faster heart rate than normal, hence categorizing it as tachycardia. In this condition, the impulse may arise from the AV node or the bundle of His, leading to a broad QRS complex on the ECG due to the reliance on the junctional pacemaker activity rather than the sinus node. This distinguishes junctional tachycardia from other tachycardias such as sinus tachycardia, where the rhythm originates from the sinus node, or accelerated junctional rhythm, which has a ventricular rate typically between 60-100 beats per minute. Ventricular fibrillation, on the other hand, is a chaotic rhythm that lacks organized electrical activity in the ventricles and is not characterized by a specific heart rate, making it distinct from junctional tachycardia.