Which of the following represents ventricular depolarization on ECG?
**Core Concept**
The electrocardiogram (ECG) is a tool used to monitor the electrical activity of the heart. Ventricular depolarization is the process by which the ventricles of the heart contract, initiated by an electrical impulse. This process is represented on the ECG by a specific waveform.
**Why the Correct Answer is Right**
Ventricular depolarization is represented by the **QRS complex** on the ECG, which is the portion of the waveform that indicates the ventricles are depolarizing and contracting. The QRS complex is a rapid upward and downward deflection, typically lasting less than 120 milliseconds. It is the most prominent part of the ECG waveform.
**Why Each Wrong Option is Incorrect**
**Option A:** This option does not correctly represent ventricular depolarization.
**Option B:** This option also does not represent ventricular depolarization.
**Option D:** This is incorrect as it does not signify ventricular depolarization.
**Clinical Pearl / High-Yield Fact**
The QRS complex is a crucial part of the ECG, as it signifies the contraction of the ventricles. A widened QRS complex can indicate a problem with ventricular depolarization.
**Correct Answer:** C. QRS complex