Cardiovascular - AV Blocks

n this episode, we review atrioventricular (AV) blocks, focusing on the mechanisms, EKG findings, clinical presentation, and management of first-, second-, and third-degree heart block. We discuss how conduction delays through the AV node can range from benign prolongation of the PR interval to complete electrical dissociation between the atria and ventricles. Key distinctions between Mobitz type I (Wenckebach) and Mobitz type II are emphasized, along with the life-threatening implications of complete heart block. Clinical symptoms such as bradycardia, dizziness, syncope, fatigue, and hypotension are reviewed, as well as important causes including ischemic heart disease, medications, fibrosis, and increased vagal tone. We also cover hallmark EKG patterns, indications for pacing, and high-yield clinical pearls to help listeners confidently recognize and manage AV conduction abnormalities in both exams and clinical practice. References Bushardt RL, Colomb-Lippa DM, Klinger AM, Reed H. The JAAPA QRS Review for PAs: Study Plan and Guide for PANCE and PANRE. 1st ed. LWW; 2021. ISBN: 9781975143817 Ahmed I. Atrioventricular Block. StatPearls [Internet]. February 12, 2024. Accessed March 15, 2026. https://www.ncbi.nlm.nih.gov/books/NBK459147/. Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay. Journal of the American College of Cardiology. 2019;74(7). doi:10.1016/j.jacc.2018.10.044 Wung S-F. Bradyarrhythmias. Critical Care Nursing Clinics of North America. 2016;28(3):297-308. doi:10.1016/j.cnc.2016.04.003