What does the QRS complex in an ECG represent?

The QRS complex in an electrocardiogram (ECG) represents the electrical activity associated with ventricular contraction, also known as depolarization of the ventricles. This is a crucial part of the cardiac cycle as it indicates that the ventricles are preparing to contract, allowing for blood to be pumped to the lungs and the rest of the body.

During this phase, the electrical impulse travels through the ventricles, resulting in their contraction. The sharp deflections seen in the QRS complex indicate that this process is happening rapidly. It usually follows the P wave, which indicates atrial depolarization and contraction, leading into the QRS complex's representation of ventricular activity.

Understanding the QRS complex is critical for interpreting an ECG, as it helps healthcare providers assess the heart's function, identify potential abnormalities, and diagnose various cardiac conditions effectively.