Explain the transmission of the electrical impulse within the heart from where it begins in the right atrium to where it ends within the ventricles?

The electrical impulse in the heart begins in the sinoatrial (SA) node and travels across the walls of the right atrium to the atrioventricular (AV) node. WHie the impulse travels the atria have time to contract. Once the impulse hits the AV node the signal is transmitted to the Bundle of His (AV bundle) and then on the the intraventricular fibers (purkinje fibers) in the septum and the outer chamber walls of the heart . This results in a simultaneous ventricular contraction.