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Pediatric Left Bundle Branch Block Follow-up

  • Author: Bahram Kakavand, MD, FACC; Chief Editor: Stuart Berger, MD  more...
Updated: Jan 12, 2015

Further Outpatient Care

Left bundle branch block may rarely progress to complete heart block and sudden death. In these patients, prognosis depends on the associated cardiac disease more than the left bundle branch block itself. Yearly evaluation, including ECG, is recommended, with follow-up more frequent than this if indicated by underlying cardiac disease and changes in patient's clinical course and symptoms.

Patients with left bundle branch block, left axis deviation, and first-degree heart block or left bundle branch block and near-syncope or complete syncope require close follow-up care. They should be referred for consultation with an electrophysiologist and possibly pacemaker insertion.

Patients with left bundle branch block need evaluation at regular intervals for possible left ventricular dysfunction. This may happen years after the onset of left bundle branch block.

For patient education resources, see the Heart Health Center.

Contributor Information and Disclosures

Bahram Kakavand, MD, FACC Assistant Professor of Pediatrics, Pediatric Cardiology and Electrophysiology, University of Kentucky College of Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

Alvin J Chin, MD Emeritus Professor of Pediatrics, University of Pennsylvania School of Medicine

Alvin J Chin, MD is a member of the following medical societies: American Association for the Advancement of Science, Society for Developmental Biology, American Heart Association

Disclosure: Nothing to disclose.

Chief Editor

Stuart Berger, MD Medical Director of The Heart Center, Children's Hospital of Wisconsin; Associate Professor, Department of Pediatrics, Section of Pediatric Cardiology, Medical College of Wisconsin

Stuart Berger, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology, American College of Chest Physicians, American Heart Association, Society for Cardiovascular Angiography and Interventions

Disclosure: Nothing to disclose.

Additional Contributors

Christopher Johnsrude, MD, MS Chief, Division of Pediatric Cardiology, University of Louisville School of Medicine; Director, Congenital Heart Center, Kosair Children's Hospital

Christopher Johnsrude, MD, MS is a member of the following medical societies: American Academy of Pediatrics, American College of Cardiology

Disclosure: Nothing to disclose.


The authors and editors of Medscape Drugs & Diseases gratefully acknowledge the contributions of previous author Christopher Mart, MD, to the development and writing of this article.

  1. Flowers NC. Left bundle branch block: a continuously evolving concept. J Am Coll Cardiol. 1987 Mar. 9(3):684-97. [Medline].

  2. Chien SJ, Liang CD, Lin IC, Lin YJ, Huang CF. Myocarditis complicated by complete atrioventricular block: nine years' experience in a medical center. Pediatr Neonatol. 2008 Dec. 49(6):218-22. [Medline].

  3. Blanc JJ, Fatemi M, Bertault V, et al. Evaluation of left bundle branch block as a reversible cause of non-ischaemic dilated cardiomyopathy with severe heart failure. A new concept of left ventricular dyssynchrony-induced cardiomyopathy. Europace. 2005 Nov. 7(6):604-10. [Medline].

  4. Diogenes MS, Succi RC, Machado DM, et al. Cardiac longitudinal study of children perinatally exposed to human immunodeficiency virus type 1 [in Portuguese]. Arq Bras Cardiol. 2005 Oct. 85(4):233-40. [Medline].

  5. Kasmani R, Okoli K, Mohan G, Casey K, Ledrick D. Transient left bundle branch block: an unusual electrocardiogram in acute pulmonary embolism. Am J Med Sci. 2009 May. 337(5):381-2. [Medline].

  6. Calabro MP, Cerrito M, Luzza F, Oreto G. Alternating right and left bundle branch block aberration during atrial tachycardia. J Electrocardiol. 2009 Apr 17. [Medline].

  7. Rivard L, Schram G, Asgar A, et al. Electrocardiographic and electrophysiological predictors of atrioventricular block after transcatheter aortic valve replacement. Heart Rhythm. 2014 Oct 31. [Medline].

  8. Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices) developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008 May 27. 51(21):e1-62. [Medline].

  9. Shen X, Aronow WS, Holmberg MJ, et al. Cardiac resynchronization therapy in patients with intrinsic and right ventricular pacing-induced left bundle branch block pattern. Am J Ther. 2009 Nov-Dec. 16(6):e44-50. [Medline].

  10. Delnoy PP, Ottervanger JP, Luttikhuis HO, et al. Long-term clinical response of cardiac resynchronization after chronic right ventricular pacing. Am J Cardiol. 2009 Jul 1. 104(1):116-21. [Medline].

  11. Becker AE, Anderson RH. Morphology of the human atrioventricular junctional area. Wellens JHH, Lie KI, Janse MJ, eds. The Conduction System of the Heart. Philadelphia, PA: Lea & Febiger; 1976. 263-71.

  12. Castellanos A, Kessler KM, Myerburg RJ. The resting electrocardiogram. Schlant RC, Alexander RW, eds. Hurst's The Heart. 8th ed. New York, NY: McGraw-Hill Medical; 1994. 330-7.

  13. Colvin EV. Cardiac embryology. Garson A, Bricker JT, Fisher DJ, Neish SR, eds. The Science and Practice of Pediatric Cardiology. 2nd ed. Baltimore, MD: Williams & Wilkins; 1998. 91-123.

  14. Demoulin JC, Kulbertus HE. Histopathologic correlates of left posterior fascicular block. Am J Cardiol. 1979 Nov. 44(6):1083-8. [Medline].

  15. Dubin D. Rapid Interpretation of EKGs. 3rd ed. Tampa, FL: Cover; 1984. 137-42.

  16. Garson A. Interventricular conduction disturbances. The Electrocardiogram in Infants and Children: A Systematic Approach. Philadelphia, PA: Lea & Febiger; 1983. 119-42.

  17. Garson A. Electrocardiography. Garson A, Bricker JT, Fisher DJ, Neish SR, eds. The Science and Practice of Pediatric Cardiology. 2nd ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 1997. 736.

  18. Gillette PC, Garson A. Pediatric Arrhythmias: Electrophysiology and Pacing. Philadelphia, PA: WB Saunders; 1990. 317-27.

  19. Hamby RI, Weissman RH, Prakash MN, Hoffman I. Left bundle branch block: a predictor of poor left ventricular function in coronary artery disease. Am Heart J. 1983 Sep. 106(3):471-7. [Medline].

  20. Husson GS, Blackman MS, Rogers MC, et al. Familial congenital bundle branch system disease. Am J Cardiol. 1973 Sep 7. 32(3):365-9. [Medline].

  21. James TN. The connecting pathways between the sinus node and A-V node and between the right and the left atrium in the human heart. Am Heart J. 1963 Oct. 66:498-508. [Medline].

  22. Keefe DL, Griffin JC, Harrison DC, Stinson EB. Atrioventricular conduction abnormalities in patients undergoing isolated aortic or mitral valve replacement. Pacing Clin Electrophysiol. 1985 May. 8(3 Pt 1):393-8. [Medline].

  23. Krikler DM, Lefevre D. Intermittent left bundle-branch block without obvious heart-disease. Lancet. 1970 Mar 7. 1(7645):498-500. [Medline].

  24. Leibman J, Plonsey R, Gillette PC. Interruption of conduction abnormalities. Pediatric Electrocardiography. Philadelphia, PA: Lippincott Williams & Wilkins; 1985. 172-91.

  25. Li TC, Hu DY, Bian H, et al. Effects of transcatheter closure of perimembranous ventricular septal defects: intermediate and long-term follow-up of 68 cases [in Chinese]. Zhonghua Yi Xue Za Zhi. 2005 Oct 26. 85(40):2846-9. [Medline].

  26. Lopes VM, Miguel JM, dos Reis DD, et al. Left-posterior hemiblock. Clinical and vectorcardiographic study of twenty cases. J Electrocardiol. 1974. 7(3):197-214. [Medline].

  27. Massing GK, James TN. Anatomical configuration of the His bundle and bundle branches in the human heart. Circulation. 1976 Apr. 53(4):609-21. [Medline].

  28. Milliken JA. Isolated and complicated left anterior fascicular block: a review of suggested electrocardiographic criteria. J Electrocardiol. 1983 Apr. 16(2):199-211. [Medline].

  29. Perloff JK, Roberts NK, Cabeen WR Jr. Left axis deviation: a reassessment. Circulation. 1979 Jul. 60(1):12-21. [Medline].

  30. Pickhoff AS. Electrophysiology: development and function of the cardiac conduction system. Allen HD, Gutgesell HP, Clark EB, Driscoll DJ, eds. Heart Disease in Infants, Children, and Adolescents: Including the Fetus and Young Adult. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2000. 414-24.

  31. Rossi L. Histopathology of Cardiac Arrhythmias. 2nd ed. Philadelphia, PA: Lea & Febiger; 1979. 1-75.

  32. Schaal SF, Seidensticker J, Goodman R, Wooley CF. Familial right bundle-branch block, left axis deviation, complete heart block, and early death. A heritable disorder of cardiac conduction. Ann Intern Med. 1973 Jul. 79(1):63-6. [Medline].

  33. Sharratt GP, Virmani S. Left-axis deviation in otherwise healthy children. Pediatr Cardiol. 1985. 6(1):7-9. [Medline].

  34. Shaver JA, Salerni R. Auscultation of the heart. Schlant RC, Alexander RW, eds. Hurst's The Heart. 8th ed. New York, NY: McGraw Hill Medical; 1994. 269.

  35. Silka MJ. Bundle branch block. Garson A, Bricker JT, Fisher DJ, Neish SR, eds. The Science and Practice of Pediatric Cardiology. Philadelphia, PA: Lippincott, Williams & Wilkins; 1997. 2033-45.

  36. Stollberger C, Winkler-Dworak M, Blazek G, et al. Age-dependency of cardiac and neuromuscular findings in left ventricular noncompaction. Int J Cardiol. 2006 Jul 28. 111(1):131-5. [Medline].

  37. Sun XJ, Gao W, Zhou AQ, et al. Risk factors for arrhythmia early after transcatheter closure of perimembranous ventricular septal defects [in Chinese]. Zhonghua Er Ke Za Zhi. 2005 Oct. 43(10):767-71. [Medline].

  38. Tawara S. Das Reizleitungssystem des Saugetierkerzens. Jena: Gustav Fisher; 1906.

  39. Van Praagh R, Van Praagh S. Morphologic anatomy. In: Fyler, DC, ed. Nadas' Pediatric Cardiology. Philadelphia, PA: Hanley & Belfus; 1992. 23.

  40. [Guideline] Wagner GS, Macfarlane P, Wellens H, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part VI: acute ischemia/infarction: a scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society. Endorsed by the International Society for Computerized Electrocardiology. J Am Coll Cardiol. 2009 Mar 17. 53(11):1003-11. [Medline].

  41. Waller BF, Schlant RC. Anatomy of the heart. Schlant RC, Alexander RW, eds. Hurst's The Heart. 8th ed. New York, NY: McGraw-Hill Medical; 1994. 99-102.

  42. Walsh, EP. Electrocardiography and introduction to electrophysiologic techniques. Fyler, DC, ed. Nadas' Pediatric Cardiology. Philadelphia, PA: Hanley & Belfus; 1992. 134.

  43. Youn HJ, Park CS, Cho EJ, et al. Left bundle branch block disturbs left anterior descending coronary artery flow: study using transthoracic Doppler echocardiography. J Am Soc Echocardiogr. 2005 Oct. 18(10):1093-8. [Medline].

ECGs show a normal sinus rhythm and a sinus rhythm with a left bundle branch block.
Anatomy of the penetrating portion of the atrioventricular (AV) bundle.
ECG depicts electrophysiologic events in normal cardiac conduction. AV = atrioventricular.
Pathophysiology of left bundle branch block. AV = atrioventricular; LV = left ventricular; RV = right ventricular.
ECG depicts electrophysiologic events of left bundle branch block.
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