Certified EKG Technician (CET) Practice Exam 2026 – Comprehensive Test Prep

The R wave in the QRS complex is essential for determining the regularity of the ventricular rate. This is because the R wave represents the peak of the electrical impulse that triggers ventricular contraction. By measuring the intervals between successive R waves, EKG technicians can assess the rhythm and determine if the ventricular rate is regular or irregular. Regularity is indicated by equal time intervals between the R waves, while irregularity is noted if the intervals vary.

Examining other waves, such as the P wave, which reflects atrial depolarization, or the T wave, which indicates ventricular repolarization, does not directly provide information about the ventricular rate's regularity. The S wave, also part of the QRS complex, contributes to the overall depiction of the ventricular depolarization process but is not specifically used for assessing the interval between beats, which is critical for determining regularity in the ventricular rate. Therefore, focusing on the R wave is essential for accurately evaluating the rhythm of the heart.