Certified EkG technician (CET) Practice Exam

What does a prolonged PR interval typically indicate?

1. Normal conduction through the heart

2. Impaired conduction through the AV node

3. Stable heart rhythm

4. Rapid heart rate

The correct answer is: Impaired conduction through the AV node

A prolonged PR interval typically indicates impaired conduction through the AV node. The PR interval represents the time it takes for electrical impulses to travel from the atria, through the AV node, and into the ventricles. When this interval is prolonged, it suggests that there is a delay in this conduction pathway, which can occur in various forms of atrioventricular (AV) block. This situation can lead to significant clinical implications, as it may result in the heart not coordinating effectively during each heartbeat, potentially affecting the hemodynamics of the patient. In contrast, a normal conduction through the heart would be reflected by a normal PR interval, while a stable heart rhythm does not specifically indicate delays in conduction but rather suggests that the heart beats in a consistent pattern. A rapid heart rate would typically be associated with short PR intervals rather than prolonged ones, as it usually involves different underlying mechanisms affecting heart rate and rhythm. Thus, the prolonged PR interval serves as a key indicator of issues specifically relating to AV node transmission.