Need to use the latest version of Firefox or Chrome to view video. The transmission of the impulse through the AV node and His-Purkinje system occurs during the latter half of the P wave, while the left atrium is depolarizing, and during the PR segment of the electrocardiogram. Book traversal links for 1.4.12 1.4.11 Up 1.5.0 Ventricular Depolarization