Medscape is available in 5 Language Editions – Choose your Edition here.


Atrioventricular Block Medication

  • Author: Chirag M Sandesara, MD; Chief Editor: Jeffrey N Rottman, MD  more...
Updated: Dec 18, 2014

Medication Summary

Long-term medical therapy is not indicated in atrioventricular (AV) block. Permanent pacing is the therapy of choice in advanced AV block, and it does not require concomitant medical therapy. Sometimes AV nodal blocking medications that contribute to heart block can be discontinued if not necessary. Atropine administration (0.5-1.0 mg) or isoproterenol infusion may improve AV conduction in emergencies where bradycardia is caused by a proximal AV block (located in the atrioventricular node [AVN]) but may worsen conduction if the block is in the His-Purkinje system.


Anticholinergic Agents

Class Summary

The goal of administering anticholinergic agents is to improve conduction through the AVN by reducing vagal tone via muscarinic receptor blockade. This is only effective if the site of block is within the AVN. For patients with suspected infranodal block, this therapy is ineffective and may make the level of the block worse if it is in the His bundle or below.

Atropine IV/IM (Atropair, Atropisol)


Atropine increases AV conduction. An insufficient dose may cause paradoxical slowing of the heart rate.

Isoproterenol (Isuprel)


Isoproterenol has beta1- and beta2-adrenergic receptor activity. It binds the beta-receptors of the heart, smooth muscle of bronchi, skeletal muscle, the vasculature, and the alimentary tract. It has positive inotropic and chronotropic actions.

Contributor Information and Disclosures

Chirag M Sandesara, MD Virginia Cardiovascular Associates, Cardiac Rhythm Care

Chirag M Sandesara, MD is a member of the following medical societies: American College of Cardiology, American College of Physicians-American Society of Internal Medicine, American Heart Association, American Medical Association, Heart Rhythm Society

Disclosure: Nothing to disclose.


Brian Olshansky, MD Professor Emeritus of Medicine, Department of Internal Medicine, University of Iowa College of Medicine

Brian Olshansky, MD is a member of the following medical societies: American College of Cardiology, Heart Rhythm Society, Cardiac Electrophysiology Society, American Heart Association

Disclosure: Received honoraria from Guidant/Boston Scientific for speaking and teaching; Received honoraria from Medtronic for speaking and teaching; Received consulting fee from Guidant/Boston Scientific for consulting; Received consulting fee from BioControl for consulting; Received consulting fee from Boehringer Ingelheim for consulting; Received consulting fee from Amarin for review panel membership; Received consulting fee from sanofi aventis for review panel membership.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Steven J Compton, MD, FACC, FACP, FHRS Director of Cardiac Electrophysiology, Alaska Heart Institute, Providence and Alaska Regional Hospitals

Steven J Compton, MD, FACC, FACP, FHRS is a member of the following medical societies: American College of Physicians, American Heart Association, American Medical Association, Heart Rhythm Society, Alaska State Medical Association, American College of Cardiology

Disclosure: Nothing to disclose.

Chief Editor

Jeffrey N Rottman, MD Professor of Medicine, Department of Medicine, Division of Cardiovascular Medicine, University of Maryland School of Medicine; Cardiologist/Electrophysiologist, University of Maryland Medical System and VA Maryland Health Care System

Jeffrey N Rottman, MD is a member of the following medical societies: American Heart Association, Heart Rhythm Society

Disclosure: Nothing to disclose.


The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous authors Wojciech Zareba, MD, PhD, FACC, and Stacy D Fisher, MD, to the development and writing of the source article.

  1. [Guideline] Epstein AE, Dimarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: executive summary. Heart Rhythm. 2008 Jun. 5(6):934-55. [Medline].

  2. [Guideline] Epstein AE, DiMarco JP, Ellenbogen KA, Estes NA 3rd, Freedman RA, Gettes LS, et al. 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2013 Jan 22. 61(3):e6-75. [Medline].

  3. Schott JJ, Alshinawi C, Kyndt F, et al. Cardiac conduction defects associate with mutations in SCN5A. Nat Genet. 1999 Sep. 23(1):20-1. [Medline].

  4. Nery PB, Beanlands RS, Nair GM, Green M, Yang J, McArdle BA, et al. Atrioventricular block as the initial manifestation of cardiac sarcoidosis in middle-aged adults. J Cardiovasc Electrophysiol. 2014 Aug. 25(8):875-81. [Medline].

  5. Saleh F, Greene EA, Mathison D. Evaluation and management of atrioventricular block in children. Curr Opin Pediatr. 2014 Jun. 26(3):279-85. [Medline].

  6. Cheng S, Keyes MJ, Larson MG, et al. Long-term outcomes in individuals with prolonged PR interval or first-degree atrioventricular block. JAMA. 2009 Jun 24. 301(24):2571-7. [Medline]. [Full Text].

  7. Crisel RK, Farzaneh-Far R, Na B, Whooley MA. First-degree atrioventricular block is associated with heart failure and death in persons with stable coronary artery disease: data from the Heart and Soul Study. Eur Heart J. 2011 Aug. 32(15):1875-80. [Medline].

  8. Kuleva M, Le Bidois J, Decaudin A, et al. Clinical course and outcome of antenatally detected atrioventricular block: experience of a single tertiary centre and review of the literature. Prenat Diagn. 2014 Dec 8. [Medline].

  9. Stiles S. BLOCK-HF: replace RV pacing with BiV in AV-block heart failure. Heartwire. Nov 8, 2012. [Full Text].

First-degree atrioventricular block. PR interval is constant and is 280 msec.
Second-degree atrioventricular block, Mobitz type I (Wenckebach). Note the prolongation of the PR interval preceding the dropped beat and the shortened PR interval following the dropped beat.
Second-degree atrioventricular block, Mobitz type II. A constant PR interval in conducted beats is present. Intraventricular conduction delay also is present.
Third-degree atrioventricular block (complete heart block). The atrial rate is faster than the ventricular rate, and no association exists between the atrial and ventricular activity.
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.