Certified Rhythm Analysis Technician (CRAT) Practice Exam 2025 – All-in-One Study Guide for Exam Success!

The PR interval on an ECG represents the period during which electrical impulses travel from the atria to the ventricles. It starts at the onset of atrial depolarization (the P wave) and ends at the onset of ventricular depolarization (the QRS complex). This interval includes the time necessary for the electrical signal to pass through the atrioventricular (AV) node, which is crucial for ensuring that the atria have time to contract and pump blood into the ventricles before the ventricles contract.

Understanding the PR interval is important in clinical practice because a prolonged or shortened PR interval can indicate underlying conduction abnormalities, such as first-degree heart block or Wolf-Parkinson-White syndrome. By analyzing this interval, healthcare providers can gather critical information about the electrical conduction system of the heart, thereby assisting in diagnosing various cardiac conditions.