What does the QRS complex represent in an ECG?

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The QRS complex in an electrocardiogram (ECG) represents the depolarization of the ventricles. During this phase, the electrical impulse that spreads through the heart's conduction system leads to the contraction of the ventricles. The rapid depolarization is observable as the large spike in the QRS complex, which reflects the strong electrical activity occurring in the ventricles as they prepare to pump blood to the lungs and the rest of the body.

Understanding the specific components of the ECG is crucial, as each part of the graph corresponds to distinct electrical events in the heart. For instance, while the P wave indicates atrial depolarization, and the T wave signifies ventricular repolarization, the QRS complex is prominently associated with the electrical events leading to ventricular contraction. This knowledge is essential for interpreting ECGs and understanding heart function and potential abnormalities.