Patient Care Technician (PCT) AAH Practice Exam

What is the expected PRI measurement if a P wave occurs before a QRS in Accelerated Junctional Rhythm?

1. It is always greater than 0.12 seconds

2. It is always less than 0.12 seconds

3. It varies significantly

4. It remains constant

The correct answer is: It is always less than 0.12 seconds

In an Accelerated Junctional Rhythm, a characteristic feature is the presence of the junctional escape rhythm, which may alter the typical pattern seen in other rhythms. The P wave, if present, often corresponds to atrial depolarization that occurs just before the QRS complex. In this case, the PRI (P-R Interval) measures the time from the beginning of the P wave to the beginning of the QRS complex. Typically, the PRI is expected to be less than 0.12 seconds in junctional rhythms. This is primarily because of the short conduction time through the AV node, which is where the junctional rhythm originates. Since the electrical impulse originates more distal in the conduction system (in the junctional area) rather than from the SA node, it often results in a shorter interval as compared to normal sinus rhythm. This characteristic helps in identifying accelerated junctional rhythms during an ECG analysis, making it essential for PCTs or healthcare professionals to understand these measurements for accurate interpretation and appropriate patient management.