RT Book, Section A1 Vijayaraman, Pugazhendhi A1 Arkles, Jeffrey A1 Koneru, Jayanthi N. A1 Callans, David J. A2 Fuster, Valentin A2 Narula, Jagat A2 Vaishnava, Prashant A2 Leon, Martin B. A2 Callans, David J. A2 Rumsfeld, John S. A2 Poppas, Athena SR Print(0) ID 1202447686 T1 Conduction System Disturbances and Bradyarrhythmias T2 Fuster and Hurst's The Heart, 15e YR 2022 FD 2022 PB McGraw-Hill Education PP New York, NY SN 9781264257560 LK accesscardiology.mhmedical.com/content.aspx?aid=1202447686 RD 2024/12/13 AB Chapter SummaryThis chapter examines the pathophysiology of various clinical forms of conduction system disturbances and sinus node dysfunction (SND) (see Fuster and Hurst’s Central Illustration). The conduction system serves as the “translator” between the autonomic nervous system’s various demands for heart rate and coordinates electrical activation to provide efficient excitation–contraction coupling. Dysfunction can occur at any level of the electrical system, sinus node, atrioventricular (AV) conduction axis (AV node/His bundle), and intraventricular conduction (right and left bundle branches), with variable clinical effects. Many disease processes affect the electrical system, but the most prominent are aging and concomitant structural heart disease. Genetic disorders, although rare, are important to discover because they may be syndromic and can affect other family members. AV block caused by surgical trauma, particularly during transcatheter aortic valve procedures, is increasing in incidence and often requires complex decision making. Treatment primarily involves pacemaker implantation when appropriate, and the indications for pacing are reviewed. Novel technologies, including leadless pacing, conduction system pacing, and the promise of biological pacing, are also discussed.