Which ECG deflection is associated with atrial depolarization?

The P wave is the specific deflection on an electrocardiogram (ECG) that represents atrial depolarization. When the heart's electrical impulse originates from the sinoatrial (SA) node, it travels through the atria, causing them to contract and pump blood into the ventricles. This process is reflected on the ECG as the P wave, which is typically the first deflection seen in the cardiac cycle.

This electrical activity is important for understanding the heart's rhythm and function, as any abnormalities in the P wave can indicate issues with atrial health or conduction. The attributes of the P wave, such as its shape and duration, can provide valuable diagnostic information in clinical settings.

Other ECG components, like the QRS complex and the T wave, represent different phases of the cardiac cycle; specifically, the QRS complex is associated with ventricular depolarization, and the T wave represents ventricular repolarization. The U wave, while less commonly observed, is thought to relate to repolarization of the ventricular Purkinje fibers or other aspects of cardiac function. These distinctions clarify the specific role of each component of the ECG in cardiac assessment.