This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/pace.13035. This article is protected by copyright. All rights reserved. Title: Symptomatic, inspiration-induced atrio-ventricular block: treated with pacemaker implant. Diego A Hoffmann MD, Andrés Nicolás Atamañuk MD, Graciela Aurora Ruiz MD, Raul Chirife MD, Maria Cristina Tentori MD and Simón Salzberg MD. From the Cardiology Division; Juan A. Fernandez Hospital, 3356 Cerviño st. Ciudad Autonoma de Buenos Aires. Argentina. Address for correspondence: Hoffmann, Diego Andres. 2234 Lacroze Federico Av, floor 9, department A. Ciudad Autonoma de Buenos Aires. Argentina. Zip code 1426. Telephone number: 0541120864788. e-mail: dhdiegodh@gmail.com Abstract: Background: The respiratory sinus arrhythmia (RSA) is the most common cardiac arrhythmia. It consists of phasic variations of sinus cycle length produced by an autonomic reflex, and is characterized by increased heart rate during inspiration and decline in expiration. This phenomenon is due to a reduction of the parasympathetic tone during inspiration, causing a rise in the heart rate,