Certified EkG technician (CET) Practice Exam

What intervals should be assessed to determine the regularity of ventricular depolarization?

1. P-P wave interval

2. QRS complex

3. R-R wave interval

4. T-P wave interval

The correct answer is: R-R wave interval

To determine the regularity of ventricular depolarization, the R-R wave interval is critical. The R wave, which is the tallest peak in the QRS complex, represents the moment when the ventricles depolarize and contract. By measuring the interval between successive R waves, one can assess the consistency of this mechanism over time. A regular R-R interval indicates that the ventricles are depolarizing in a consistent rhythm, which is essential for normal cardiac function. Variability in these intervals may suggest arrhythmias or irregular heart rhythms, making this measurement vital for accurate cardiac assessment. In contrast, while the P-P wave interval assesses atrial depolarization, it does not provide information about the ventricular rhythm itself. The QRS complex indicates ventricular depolarization but does not measure the interval needed to evaluate regularity directly. The T-P wave interval pertains to the period between the end of ventricular depolarization and the beginning of the next atrial depolarization, which is not relevant for assessing the regularity of ventricular depolarization specifically. Thus, the R-R interval is the correct choice for determining the regularity of ventricular depolarization.