APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -In a healthy person, this originates at the sinoatrial node (SA node) and disperses into both left and right atria. Depolarization of the right atrium is responsible for the early part of the P wave, and depolarization of the left atrium is responsible for the middle and terminal portions of the P wave.

Detailed explanation-2: -The P wave is a small upward wave which represents electrical excitation or atrial depolarisation which leads to atrial contraction. The impulses of contraction start from the SA node as the P wave activates the SA node.

Detailed explanation-3: -P waves that look different may originate in the SA node but conduct abnormally through altered, damaged atria or may result from a pacemaker site that occurs outside the SA node. Impulses that arise from the atria produce P Prime (P’) that look different than the sinus P waves.

Detailed explanation-4: -Sinus P waves are usually most prominently seen in leads II and V1. A negative P wave in lead I may be due to incorrect recording of the electrocardiogram (that is, with transposition of the left and right arm electrodes), dextrocardia, or abnormal atrial rhythms. The P wave in V1 is often biphasic.