As a medical professional with expertise in cardiology, I can explain the P wave in an electrocardiogram (ECG). The P wave in an ECG is a crucial part of the heart's electrical activity that is recorded during an ECG. It represents the atrial depolarization, which is the process by which the atria (the upper chambers of the heart) contract to push blood into the ventricles (the lower chambers) before each heartbeat. The P wave is typically the first wave of the ECG cycle and is followed by the QRS complex and the T wave. The shape, duration, and amplitude of the P wave can provide important information about the heart's rhythm and the presence of certain conditions. For example, an abnormally shaped or timed P wave may indicate a problem with the heart's electrical conduction system, such as atrial fibrillation or other arrhythmias. read more >>

Atrial and ventricular depolarization and repolarization are represented on the ECG as a series of waves: the P wave followed by the QRS complex and the T wave. The P Wave. The first deflection is the P wave associated with right and left atrial depolarization.read more >>