Question

An EKG technician is measuring the intervals on an EKG tracing. Which of the following is an expected finding of impaired conduction through the AV node?

a) Prolonged PR interval
b) Shortened QT interval
c) Narrow QRS complex
d) Absence of P waves

Answer 1

A prolonged PR interval is an expected finding of impaired conduction through the AV node on an EKG, reflecting a delay of the electrical impulse between the SA node and the AV node.

Step-by-step explanation:

An expected finding of impaired conduction through the AV node on an EKG tracing is a prolonged PR interval. AV blocks, which denote delays in the conduction system of the heart, are categorized by degrees. A first-degree block is seen as a prolonged PR interval on the EKG, indicating a delay in the impulse from the SA node to the AV node. This interval includes the time for atrial depolarization, the impulse delay at the AV node, and the conduction through the bundle of His to the ventricles up to the beginning of the ventricular depolarization.

Common ECG abnormalities such as a second-degree or third-degree AV block also impact the PR interval but show more complex patterns, including some P waves not followed by a QRS complex (second-degree) or no correlation between the P waves and QRS complexes (third-degree).