Certified Cardiovascular Technician Practice Exam

Which component of the ECG represents ventricular depolarization?

1. T wave

2. P wave

3. QRS complex

4. A wave

The correct answer is: QRS complex

The component of the ECG that represents ventricular depolarization is the QRS complex. During this phase of the cardiac cycle, electrical impulses trigger the ventricles to contract, which is crucial for pumping blood to the lungs and the rest of the body. The QRS complex appears as a series of sharp deflections on the ECG tracing. It is significantly larger in amplitude compared to the P wave because the ventricles are larger than the atria and have more muscle mass to depolarize. Understanding the role of each component of the ECG is essential for interpreting cardiac function. The T wave reflects ventricular repolarization, the P wave indicates atrial depolarization, and the "A wave" is not a standard term used in ECG interpretation in this context, as it could refer to various other wave forms in different studies or measurements.