Jam with Confidence: Rock Your Certified Rhythm Analysis Technician Exam 2025!

A first degree AV block is characterized by a prolonged PR interval on an electrocardiogram (ECG). Specifically, the PR interval in this type of block is consistently longer than 0.20 seconds. This occurs because the electrical impulse traveling from the atria to the ventricles through the AV node is delayed, resulting in the longer interval.

In a first degree AV block, every atrial impulse is conducted to the ventricles, but the delay in conduction is evident in the longer duration of the PR interval. This pattern indicates a degree of impairment in the conduction system, but it does not lead to any missed beats, meaning that all P waves are followed by a QRS complex.

Other patterns described in the incorrect options represent different types of AV blocks or arrhythmias. For instance, an irregular rhythm with varying R-R intervals typically suggests a type of heart block known as a second degree AV block (type I or type II), or it could indicate atrial fibrillation. Patterns of QRS complexes without P waves indicate that the P waves are not being conducted to the ventricles, which is more consistent with a complete heart block or advanced forms of AV block. Lastly, periods of normal sinus rhythm interrupted by dropped beats indicate a