What does the QRS complex in an ECG represent?

The QRS complex in an ECG represents the depolarization of the ventricles. This is a crucial aspect of the heart's electrical activity, as the depolarization phase leads to ventricular contraction, allowing for the effective pumping of blood to the lungs and the rest of the body. The rapid depolarization seen in the QRS complex occurs after the electrical impulse travels from the atria through the bundle of His and down the Purkinje fibers, which stimulates the ventricles to contract.

Identifying the QRS complex is essential for assessing the heart's rhythm and function, as it indicates how well the ventricles are responding to electrical stimuli. Understanding the role of the QRS complex is fundamental for interpreting ECG readings and diagnosing various cardiac conditions.