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Lown-Ganong-Levine syndrome and enhanced atrioventricular nodal conduction

Philip J Podrid, MD, FACC
Section Editor
Peter J Zimetbaum, MD
Deputy Editor
Brian C Downey, MD, FACC


The term cardiac preexcitation was originally used to describe premature activation of the ventricle in patients with the Wolff-Parkinson-White syndrome. This term has been broadened to include all conditions in which antegrade ventricular activation or retrograde atrial activation occurs partially or totally via an anomalous (or accessory) pathway distinct from the normal cardiac conduction system.

The classic form of cardiac preexcitation remains the Wolff-Parkinson-White (WPW) pattern, which is characterized by a short PR interval (less than 0.12 sec) and a broad QRS complex due to a delta wave. The anatomic substrate for WPW pattern is a band of myocytes, also known as the bundle of Kent, which bridges the fibrous atrioventricular junction (ie, a direct atrial-ventricular accessory pathway that bypasses the atrioventricular node). The electrocardiographic features are a result of premature and direct ventricular myocardial activation due to conduction over the accessory pathway that directly innervates the ventricular myocardium. (See "Anatomy, pathophysiology, and localization of accessory pathways in the preexcitation syndrome" and "Epidemiology, clinical manifestations, and diagnosis of the Wolff-Parkinson-White syndrome", section on 'Electrocardiographic (ECG) findings'.)

Several other pathways have been postulated to result in cardiac preexcitation. However, most lack the histopathologic correlation that has been demonstrated for the WPW syndrome. The Lown-Ganong-Levine (LGL) pattern and enhanced atrioventricular nodal conduction (EAVNC) share some common features and have often been considered to have a similar etiology. The mechanisms proposed to account for these conditions include more rapid conduction within the AV node ("slick AV node") or as a result of a bypass of the normal AV nodal tissue (figure 1). The LGL syndrome and EAVNC will be discussed in detail here. Mahaim fiber tachycardia, another non-WPW form of preexcitation, is discussed separately. (See "Mahaim fiber tachycardias".)


The Lown-Ganong-Levine (LGL) pattern is characterized by the presence of a short PR interval and normal QRS complex on the surface electrocardiogram (ECG). This finding may represent a perinodal accessory pathway or enhanced AV nodal conduction (waveform 1). This bypass tract or accessory pathway is known as a bundle of James. This pathway links the atrial myocardium with the bundle of His. Thus, there is a short PR interval but a normal QRS complex as ventricular activation is still via the normal His-Purkinje system.

Patients with palpitations who had a short PR interval but normal QRS complex on the resting electrocardiogram (ie, LGL syndrome) were first described in 1938 and then further evaluated by Lown, Ganong, and Levine in 1952 [1,2]. The latter report consisted of a retrospective examination of 13,500 consecutive ECGs at a single tertiary care center. 200 subjects were identified with a short PR interval, most of whom had a normal QRS complex [2]. The incidence of paroxysmal supraventricular tachycardia was significantly higher in these patients when compared with a control group with a normal PR interval (11 versus 0.5 percent).

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Literature review current through: Nov 2017. | This topic last updated: Nov 13, 2017.
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  1. Clerc, A, Robert-Levy, et al. A propos du raccourcissement permanent de l'espace P-R del'electrocardiogramme sans deformation du complexe ventriculaire. Arch Mal Coeur 1938; 31:569.
  2. LOWN B, GANONG WF, LEVINE SA. The syndrome of short P-R interval, normal QRS complex and paroxysmal rapid heart action. Circulation 1952; 5:693.
  3. Benditt DG, Pritchett LC, Smith WM, et al. Characteristics of atrioventricular conduction and the spectrum of arrhythmias in lown-ganong-levine syndrome. Circulation 1978; 57:454.
  4. Caracta AR, Damato AN, Gallagher JJ, et al. Electrophysiologic studies in the syndrome of short P-R interval, normal QRS complex. Am J Cardiol 1973; 31:245.
  5. Iannone LA. Electrophysiology of atrial pacing in patients with short PR interval, normal QRS complex. Am Heart J 1975; 89:74.
  6. Bissett JK, Thompson AJ, DeSoyza N, Murphy ML. Atrioventricular conduction in patients with short PR intervals and normal QRS complexes. Br Heart J 1973; 35:123.
  7. Ward DE, Bexton R, Camm AJ. Characteristics of atrio-His conduction in the short PR interval, normal QRS complex syndrome. Evidence for enhanced slow-pathway conduction. Eur Heart J 1983; 4:882.
  8. Gallagher JJ, Sealy WC, Kasell J, Wallace AG. Multiple accessory pathways in patients with the pre-excitation syndrome. Circulation 1976; 54:571.
  9. Jackman WM, Prystowsky EN, Naccarelli GV, et al. Reevaluation of enhanced atrioventricular nodal conduction: evidence to suggest a continuum of normal atrioventricular nodal physiology. Circulation 1983; 67:441.
  10. Benditt, DG, Epstein, et al. Enhanced atrioventricular conduction in patients without preexcitation syndrome: relationship to heart rate in paroxysmal reciprocating tachycardia. Circulation 1974; 65:1982.
  11. Benditt DG, Dunbar D, Almquist A, et al. AV node bypass tracts and enhanced AV conduction: Relation to ventricular preexcitation. In: Cardiac Pre-excitation Syndromes, Benditt DG, Benson D, Woodrow DW Jr (Eds), Martinus Nijhoff, Boston 1986. p.225.
  12. Bissett JK, de Soyza N, Kane JJ, Murphy ML. Altered refractory periods in patients with short P-R intervals and normal QRS complex. Am J Cardiol 1975; 35:487.
  13. Lepehkin, E . The P-Q-R-S-T-U complex. In: Modern Electrocardiography, Williams & Wilkins, Baltimore, 1951; 1:237.
  14. JAMES TN. Morphology of the human atrioventricular node, with remarks pertinent to its electrophysiology. Am Heart J 1961; 62:756.
  15. Brechenmacher C. Atrio-His bundle tracts. Br Heart J 1975; 37:853.
  16. Anderson RH, Becker AE, Brechenmacher C, et al. Ventricular preexcitation. A proposed nomenclature for its substrates. Eur J Cardiol 1975; 3:27.
  17. Anderson RH, Becker AE, Brechenmacher C, et al. The human atrioventricular junctional area. A morphological study of the A-V node and bundle. Eur J Cardiol 1975; 3:11.
  18. Bharati S, Bauernfiend R, Scheinman M, et al. Congenital abnormalities of the conduction system in two patients with tachyarrhythmias. Circulation 1979; 59:593.
  19. Childers R. The AV node: normal and abnormal physiology. Prog Cardiovasc Dis 1977; 19:361.
  20. Prystowsky EN, Pritchett LC, Smith WM, et al. Electrophysiologic assessment of the atrioventricular conduction system after surgical correction of ventricular preexcitation. Circulation 1979; 59:789.
  21. Benditt DG, Klein GJ, Kriett JM, et al. Enhanced atrioventricular nodal conduction in man: electrophysiologic effects of pharmacologic autonomic blockade. Circulation 1984; 69:1088.
  22. Abella JB, Teixeira OH, Misra KP, Hastreiter AR. Changes of atrioventricular conduction with age in infants and children. Am J Cardiol 1972; 30:876.
  23. DuBrow W, Fisher EA, Amaty-Leon G, et al. Comparison of cardiac refractory periods in children and adults. Circulation 1975; 51:485.
  24. Meijler FL. Atrioventricular conduction versus heart size from mouse to whale. J Am Coll Cardiol 1985; 5:363.
  25. Moro C, Cosío FG. Electrophysiologic study of patients with short P-R interval and normal QRS complex. Eur J Cardiol 1980; 11:81.
  26. Josephson ME, Kastor JA. Supraventricular tachycardia in Lown-Ganong-Levine syndrome: atrionodal versus intranodal reentry. Am J Cardiol 1977; 40:521.
  27. Moleiro F, Mendoza IJ, Medina-Ravell V, et al. One to one atrioventricular conduction during atrial pacing at rates of 300/minute in absence of Wolff-Parkinson-White Syndrome. Am J Cardiol 1981; 48:789.
  28. Denes, P, Wu, et al. Demonstration of dual AV pathways in a patient with the Lown-Ganong-Levine syndrome. Chest 1974; 64:343.
  29. Bauernfeind RA, Ayres BF, Wyndham CC, et al. Cycle length in atrioventricular nodal reentrant paroxysmal tachycardia with observations on the Lown-Ganong-Levine syndrome. Am J Cardiol 1980; 45:1148.
  30. Ward DE, Camm J. Mechanisms of junctional tachycardias in the Lown-Ganong-Levine syndrome. Am Heart J 1983; 105:169.
  31. Gallagher JJ, Pritchett EL, Sealy WC, et al. The preexcitation syndromes. Prog Cardiovasc Dis 1978; 20:285.
  32. Wiener I. Syndromes of Lown-Ganong-Levine and enhanced atrioventricular nodal conduction. Am J Cardiol 1983; 52:637.
  33. Holmes DR Jr, Hartzler GO, Maloney JD. Concealed retrograde bypass tracts and enhanced atrioventricular nodal conduction. An unusual subset of patients with refractory paroxysmal supraventricular tachycardia. Am J Cardiol 1980; 45:1053.
  34. Fisher JD. Role of electrophysiologic testing in the diagnosis and treatment of patients with known and suspected bradycardias and tachycardias. Prog Cardiovasc Dis 1981; 24:25.
  35. Josephson ME. Paroxysmal supraventricular tachycardia: an electrophysiologic approach. Am J Cardiol 1978; 41:1123.
  36. Myerburg RJ, Sung RJ, Castellanos A. Ventricular tachycardia and ventricular fibrillation in patients with short P-R intervals and narrow QRS complexes. Pacing Clin Electrophysiol 1979; 2:568.
  37. Blanc, JJ, Fontaliran, et al. Electrophysiologic and histopathologic correlation (abstract). Pacing Clin Electrophysiol 1981; 4:A.
  38. Castellanos A, Vagueiro MC, Befeler B, Myerburg RJ. Syndrome of short P-R, narrow QRS and repetitive supraventricular tachyarrhythmias: the possible occurrence of the R-on-T phenomenon and the limits of this syndrome. Eur J Cardiol 1975; 2:337.
  39. Prystowsky EN, Greer S, Packer DL, et al. Beta-blocker therapy for the Wolff-Parkinson-White syndrome. Am J Cardiol 1987; 60:46D.
  40. Seipel L, Breithardt G, Both A. Atrioventricular (AV) and ventriculoatrial (VA) conduction pattern in patients with short P-R interval and normal QRS complex. In: Cardiac pacing, Luderitz B (Ed), Springer-Verlag, Berlin 1976. p.52.
  41. Moro, C, Cosio, FG . Electrophysiological study of patients with short P-R interval and normal QRS complex. Eur J Cardiol 1980; II:81.
  42. Yeung-Lai-Wah JA, Alison JF, Lonergan L, et al. High success rate of atrioventricular node ablation with radiofrequency energy. J Am Coll Cardiol 1991; 18:1753.