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Etiology of atrioventricular block

William H Sauer, MD
Section Editor
Leonard I Ganz, MD, FHRS, FACC
Deputy Editor
Brian C Downey, MD, FACC


Atrioventricular (AV) block is defined as a delay or interruption in the transmission of an impulse from the atria to the ventricles due to an anatomical or functional impairment in the conduction system. The conduction disturbance can be transient or permanent, and it can have many causes (table 1).

The conduction can be delayed, intermittent, or absent. The commonly used terminology includes first degree (slowed conduction without loss of atrioventricular synchrony), second degree (intermittent loss of atrioventricular conduction, often in a regular pattern, eg, 2:1, 3:2, or higher degrees of block), and third degree or complete AV block. (See "ECG tutorial: Atrioventricular block".)

The etiology of AV block will be reviewed here. The management of the specific types of AV block is discussed separately. (See "First degree atrioventricular block" and "Second degree atrioventricular block: Mobitz type I (Wenckebach block)" and "Second degree atrioventricular block: Mobitz type II" and "Third degree (complete) atrioventricular block".)


Increased vagal tone — Enhanced vagal tone due to sleep, athletic training, pain, carotid sinus massage, or hypersensitive carotid sinus syndrome can result in slowing of the sinus rate and/or the development of AV block. (See "Arrhythmia in athletes" and "Sick sinus syndrome: Epidemiology, etiology, and natural history" and "Carotid sinus hypersensitivity".)

Idiopathic progressive cardiac conduction disease — Fibrosis and sclerosis of the conduction system accounts for about one-half of cases of AV block and may be induced by several different conditions which often cannot be distinguished clinically [1]. Progressive cardiac conduction defects, referred to as Lenegre's or Lev's disease, are characterized by progressive impairment of the conduction system:


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Literature review current through: Nov 2016. | This topic last updated: Thu Oct 30 00:00:00 GMT+00:00 2014.
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  5. Begg FR, Magovern GJ, Cushing WJ, et al. Selective cine coronary arteriography in patients with complete heart block. J Thorac Cardiovasc Surg 1969; 57:9.
  6. Simon AB, Zloto AE. Atrioventricular block: natural history after permanent ventricular pacing. Am J Cardiol 1978; 41:500.
  7. LEVINE SA, MILLER H, PENTON GB. Some clinical features of complete heart block. Circulation 1956; 13:801.
  8. HEJTMANCIK MR, HERRMANN GR, SHIELDS AH, WRIGHT JC. A clinical study of complete heart block. Am Heart J 1956; 52:369.
  9. ROWE JC, WHITE PD. Complete heart block: a follow-up study. Ann Intern Med 1958; 49:260.
  10. Killip T 3rd, Kimball JT. Treatment of myocardial infarction in a coronary care unit. A two year experience with 250 patients. Am J Cardiol 1967; 20:457.
  11. Godman MJ, Lassers BW, Julian DG. Complete bundle-branch block complicating acute myocardial infarction. N Engl J Med 1970; 282:237.
  12. Sugiura T, Iwasaka T, Hasegawa T, et al. Factors associated with persistent and transient fascicular blocks in anterior wall acute myocardial infarction. Am J Cardiol 1989; 63:784.
  13. Mullins CB, Atkins JM. Prognoses and management of venticular conduction blocks in acute myocardial infarction. Mod Concepts Cardiovasc Dis 1976; 45:129.
  14. Hindman MC, Wagner GS, JaRo M, et al. The clinical significance of bundle branch block complicating acute myocardial infarction. 1. Clinical characteristics, hospital mortality, and one-year follow-up. Circulation 1978; 58:679.
  15. Scheinman MM, Gonzalez RP. Fascicular block and acute myocardial infarction. JAMA 1980; 244:2646.
  16. Dubois C, Piérard LA, Smeets JP, et al. Short- and long-term prognostic importance of complete bundle-branch block complicating acute myocardial infarction. Clin Cardiol 1988; 11:292.
  17. Harris A, Davies M, Redwood D, et al. Aetiology of chronic heart block. A clinico-pathological correlation in 65 cases. Br Heart J 1969; 31:206.
  18. Bernstein M. Auriculoventricular dissociation following scarlet fever: Report of a case. Am Heart J 1938; 16:582.
  19. Rantz LA, Spink WW, Boisvert PJ. Abnormalities in the electrocardiogram following hemolytic streptococcus sore throat. Arch Intern Med 1946; 77:66.
  20. Lev M, Bharati S, Hoffman FG, Leight L. The conduction system in rheumatoid arthritis with complete atrioventricular block. Am Heart J 1975; 90:78.
  21. CLARK NS. Complete heart block in children; report of three cases possibly attributable to measles. Arch Dis Child 1948; 23:156.
  22. Rosenberg DH. Electrocardiographic changes in epidemic parotitis (mumps). Proc Soc Exp Biol Med 1945; 58:9.
  23. ENGLE MA. Recovery from complete heart block in diphtheria. Pediatrics 1949; 3:222.
  24. Menon TB, Rao CK. Tuberculosis of the Myocardium Causing Complete Heart Block. Am J Pathol 1945; 21:1193.
  26. Lim CH, Toh CC, Chia BL, Low LP. Stokes-Adams attacks due to acute nonspecific myocarditis. Am Heart J 1975; 90:172.
  27. Wray R, Iveson M. Complete heart block and systemic lupus erythematosus. Br Heart J 1975; 37:982.
  28. Kleid JJ, Kim ES, Brand B, et al. Heart block complicating acute bacterial endocarditis. Chest 1972; 61:301.
  29. Schott JJ, Alshinawi C, Kyndt F, et al. Cardiac conduction defects associate with mutations in SCN5A. Nat Genet 1999; 23:20.
  30. Tan HL, Bink-Boelkens MT, Bezzina CR, et al. A sodium-channel mutation causes isolated cardiac conduction disease. Nature 2001; 409:1043.
  31. Wang DW, Viswanathan PC, Balser JR, et al. Clinical, genetic, and biophysical characterization of SCN5A mutations associated with atrioventricular conduction block. Circulation 2002; 105:341.
  32. Herfst LJ, Potet F, Bezzina CR, et al. Na+ channel mutation leading to loss of function and non-progressive cardiac conduction defects. J Mol Cell Cardiol 2003; 35:549.
  33. Probst V, Kyndt F, Potet F, et al. Haploinsufficiency in combination with aging causes SCN5A-linked hereditary Lenègre disease. J Am Coll Cardiol 2003; 41:643.
  34. Royer A, van Veen TA, Le Bouter S, et al. Mouse model of SCN5A-linked hereditary Lenègre's disease: age-related conduction slowing and myocardial fibrosis. Circulation 2005; 111:1738.
  35. McNair WP, Ku L, Taylor MR, et al. SCN5A mutation associated with dilated cardiomyopathy, conduction disorder, and arrhythmia. Circulation 2004; 110:2163.
  36. Olson TM, Michels VV, Ballew JD, et al. Sodium channel mutations and susceptibility to heart failure and atrial fibrillation. JAMA 2005; 293:447.
  37. Makiyama T, Akao M, Tsuji K, et al. High risk for bradyarrhythmic complications in patients with Brugada syndrome caused by SCN5A gene mutations. J Am Coll Cardiol 2005; 46:2100.
  38. Brink PA, Ferreira A, Moolman JC, et al. Gene for progressive familial heart block type I maps to chromosome 19q13. Circulation 1995; 91:1633.
  39. Schott JJ, Benson DW, Basson CT, et al. Congenital heart disease caused by mutations in the transcription factor NKX2-5. Science 1998; 281:108.
  40. Ikeda Y, Hiroi Y, Hosoda T, et al. Novel point mutation in the cardiac transcription factor CSX/NKX2.5 associated with congenital heart disease. Circ J 2002; 66:561.
  41. Jay PY, Harris BS, Maguire CT, et al. Nkx2-5 mutation causes anatomic hypoplasia of the cardiac conduction system. J Clin Invest 2004; 113:1130.
  42. Pashmforoush M, Lu JT, Chen H, et al. Nkx2-5 pathways and congenital heart disease; loss of ventricular myocyte lineage specification leads to progressive cardiomyopathy and complete heart block. Cell 2004; 117:373.
  43. Arnsdorf MF, Schreiner E, Gambetta M, et al. Electrophysiological changes in the canine atrium and ventricle during progressive hyperkalaemia: electrocardiographical correlates and the in vivo validation of in vitro predictions. Cardiovasc Res 1977; 11:409.
  44. Surawicz B. Relationship between electrocardiogram and electrolytes. Am Heart J 1967; 73:814.
  45. Fisch C. Relation of electrolyte disturbances to cardiac arrhythmias. Circulation 1973; 47:408.
  46. Roberts NK, Perloff JK, Kark RA. Cardiac conduction in the Kearns-Sayre syndrome (a neuromuscular disorder associated with progressive external ophthalmoplegia and pigmentary retinopathy). Report of 2 cases and review of 17 published cases. Am J Cardiol 1979; 44:1396.
  47. Sanyal SK, Johnson WW. Cardiac conduction abnormalities in children with Duchenne's progressive muscular dystrophy: electrocardiographic features and morphologic correlates. Circulation 1982; 66:853.
  48. Komajda M, Frank R, Vedel J, et al. Intracardiac conduction defects in dystrophia myotonica. Electrophysiological study of 12 cases. Br Heart J 1980; 43:315.
  49. Hsu YJ, Lin YF, Chau T, et al. Electrocardiographic manifestations in patients with thyrotoxic periodic paralysis. Am J Med Sci 2003; 326:128.
  50. James TN, Carson DJ, Marshall TK. De subitaneis mortibus. I. Fibroma compressing His bundle. Circulation 1973; 48:428.
  51. den Dulk K, Brugada P, Braat S, et al. Myocardial bridging as a cause of paroxysmal atrioventricular block. J Am Coll Cardiol 1983; 1:965.
  52. Rosen KM, Heller R, Ehsani A, Rahimtoola SH. Localization of site of traumatic heart block with His bundle recordings: electrophysiologic observations regarding the nature of "split" H potentials. Am J Cardiol 1972; 30:412.
  53. Zeltser D, Justo D, Halkin A, et al. Drug-induced atrioventricular block: prognosis after discontinuation of the culprit drug. J Am Coll Cardiol 2004; 44:105.
  54. Sanoudos G, Reed GE. Late heart block in aortic valve replacement. J Cardiovasc Surg (Torino) 1974; 15:475.
  55. Rosen KM, Mehta A, Rahimtoola SH, Miller RA. Sites of congenital and surgical heart block as defined by His bundle electrocardiography. Circulation 1971; 44:833.
  56. Furman S, Young D. Cardiac pacing in children and adolescents. Am J Cardiol 1977; 39:550.
  57. Hofschire PJ, Nicoloff DM, Moller JH. Postoperative complete heart block in 64 children treated with and without cardiac pacing. Am J Cardiol 1977; 39:559.
  58. Berdajs D, Schurr UP, Wagner A, et al. Incidence and pathophysiology of atrioventricular block following mitral valve replacement and ring annuloplasty. Eur J Cardiothorac Surg 2008; 34:55.
  59. Thanopoulos BD, Rigby ML. Outcome of transcatheter closure of muscular ventricular septal defects with the Amplatzer ventricular septal defect occluder. Heart 2005; 91:513.
  60. Khawaja MZ, Rajani R, Cook A, et al. Permanent pacemaker insertion after CoreValve transcatheter aortic valve implantation: incidence and contributing factors (the UK CoreValve Collaborative). Circulation 2011; 123:951.
  61. Eltchaninoff H, Prat A, Gilard M, et al. Transcatheter aortic valve implantation: early results of the FRANCE (FRench Aortic National CoreValve and Edwards) registry. Eur Heart J 2011; 32:191.
  62. Baan J Jr, Yong ZY, Koch KT, et al. Factors associated with cardiac conduction disorders and permanent pacemaker implantation after percutaneous aortic valve implantation with the CoreValve prosthesis. Am Heart J 2010; 159:497.
  63. Roten L, Wenaweser P, Delacrétaz E, et al. Incidence and predictors of atrioventricular conduction impairment after transcatheter aortic valve implantation. Am J Cardiol 2010; 106:1473.