RT Book, Section A1 Teply-Kondrack, Robyn A1 Packard, Kathleen A2 Sutton, S. Scott SR Print(0) ID 7250601 T1 Chapter 8. Arrhythmias T2 McGraw-Hill's NAPLEX® Review Guide YR 2011 FD 2011 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-175562-7 LK accesspharmacy.mhmedical.com/content.aspx?aid=7250601 RD 2024/04/20 AB Normal conduction and cardiac rhythm is initiated by the sinoatrial (SA) node. The electrical current then travels through the conduction network and enters the ventricle via the atrioventricular (AV) node and bundle of His. From the bundle of His, the electrical activity moves into the branch-like system called the Purkinje system. As the current flows through the myocardium, the excitation coordinates the contraction of the atria and ventricles. After stimulation, each group of cells experiences a refractory period in which it cannot be excited. As the electrical current meets refractory tissue, the stimulation ceases allowing for the process to begin again.1