What does the QRS complex on an ECG indicate?

The QRS complex on an ECG is a critical component that represents ventricular depolarization. During this phase, the electrical impulses spread through the ventricles, causing them to contract and pump blood to the lungs and the rest of the body. This complex occurs after the P wave, which reflects atrial depolarization, and precedes the T wave, which signifies ventricular repolarization.

Understanding the significance of the QRS complex is fundamental in interpreting ECG readings. A narrow QRS complex typically indicates that the electrical conduction is normal, while a wide QRS complex can suggest conditions such as bundle branch blocks or other forms of ventricular conduction delays. The health and efficiency of the ventricles can be assessed through the characteristics of the QRS complex, thus making it vital for diagnosing various cardiac conditions.