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Lidocain Mexiletin

Chinidin Ajmalin Disopyramid

Fig. 7. Antiarrhythmic drug effects on the ventricular action potential. Effects of various antiar-rhythmic drugs on the ventricular action potential. The unbroken line (a) represents the control state. The circles indicate the level of repolarization at which the fiber becomes reexcitable (ERP = effective refractory period). Action potential duration and the QT-interval are prolonged in b under the effect of Quinidine or Procainamide and shortened when exposed to Lidocain (c)

whereas Dirk Durrer and Henrick JJ Wellens were the first who executed programmed stimulation in men (Fig. 6) (65,66). The programmed stimulation technique has in firstline been used to induce ventricular tachycardia and to elucidate the mechanisms of tachycardias in the Wolff-Parkinson-White-Syndrome (67). Electrophysiologic testing was then more and more used to guide pharmacological therapy and to delineate the electrophysiologic effects of drugs on the normal and diseased myocardium (68). The registration of the action potential in the experimental laboratory and in the intact human heart via catheter technique did substantially change our mechanisms in cellular de- and repolarization (69-71), antiarrhythmic drug effects (Fig. 7) (72-75), and arrhythmo-genesis (76,77).

In the late 18th century the Italian scientist Felice Fontana described a phenomenon later called the refractory period while he was investigating irregular impulses of the heart (78). Subsequently, Moritz Schiff, a German physiologist (Fig. 8), reported in 1850 that a strong electrical stimulus that has been delivered during the late refractory period of cardiac muscle could induce a contraction. Confirmation of these findings was achieved by Hugo Kronecker and the French physiologist Etienne Jules Marey, who performed a first documentation of phenomenons like premature ventricular beats using a polygraph recording of the radial and apical impulse simultaneously (79). Schiff's, Kroneckers's, and Marey's experiments have been completed by the work of Anton Carlson, an American physiologist, who established the still accepted concept of absolute and relative

History of Repolarization

Fig. 8. Moritz Schiff (1823-1896).

refractory periods in cardiac tissue (80). In 1920 Bazett described the relationship between rate and the duration of the QT-interval in 39 normal subjects (81). He summarized, that the QT interval varies with the square root of the cycle length:


The constant k has been fixed to 0.37 in men and 0.4 in women by Bazett. Later on Shipley and coworkers changed these values to 0.397 and 0.415 respectively after investigating 200 normal subjects (82). Today, the Bazett calculation is generally used as QTc = QT^R-R. Thus the QTc-interval is corrected or normalized to the QT interval at a heart rate of 60 beats/min. Several attempts have been made since to modify or substitute the Bazett calculation to gain a still better expression of the cardiac physiology. Fridericia for example proposed a cube root formula in 1920 after analyzing 50 normal subjects where QT = k(constant) x ^R-R (82). However, comparing the cube root formula to the normal range of the QT interval, this calculation gives too short intervals at low rates and too long intervals at high rates. Subsequently, Ashman proposed a logarithmic formula in 1942 with QT = k1 x log (10 x [R-R + k2]) with the disadvantage of this type of calculation again exhibiting too low intervals at low heart rates (83). A straight-line formula has also been discussed by various investigators (84-88), however the Bazett calculation is still the most widely accepted. It has also been Ashman who investigated the relationship of heart rate and the refractory period; he described first that aberration can be induced by prolongation of the preceding cycle, an observation which is commonly referred to as the Ashman phenomenon (89).

flu. 1.—T<Kmod J. (ul ECC: Julï H). 1013. during rm. Uu<l( I, II, III. Iv Ft. Q-T u.ftu ««. :: H - 11 g stir. (6) bcci ■ 1Î0. :i.onila i, II. iii. iv li. Q-T -0.(10 iiw. K-TC - 0 N/i ■■

Fig. 9. Jervell and Lange-Nielsen syndrome. A combination of deaf-mutism and a peculiar heart disease has been observed in 4 children in a family of 6. The parents were not related, and were, as the other 2 children, who otherwise seemed quite healthy and had normal hearing. The deaf-mute children, who otherwise seemed quite healthy, suffered from fainting attacks "occurring from the age to 3 to years. By clinical and roentgen examination, which was performed in 3 of the children, no signs of heart disease could be discovered. The electrocardiograms, however, revealed a pronounced prolongation of the QT interval in all cases. Three of the deaf-mute children died suddenly at the ages of 4, 5, and 9 years respectively."

Reproduced from Jervell A, Lange-Nielsen F: Congenital deaf mutism, functional heart disease with prolongation of the QT interval, and sudden death. Am Heart J 1957;54:59-68 with permission.

flu. 1.—T<Kmod J. (ul ECC: Julï H). 1013. during rm. Uu<l( I, II, III. Iv Ft. Q-T u.ftu ««. :: H - 11 g stir. (6) bcci ■ 1Î0. :i.onila i, II. iii. iv li. Q-T -0.(10 iiw. K-TC - 0 N/i ■■

Fig. 9. Jervell and Lange-Nielsen syndrome. A combination of deaf-mutism and a peculiar heart disease has been observed in 4 children in a family of 6. The parents were not related, and were, as the other 2 children, who otherwise seemed quite healthy and had normal hearing. The deaf-mute children, who otherwise seemed quite healthy, suffered from fainting attacks "occurring from the age to 3 to years. By clinical and roentgen examination, which was performed in 3 of the children, no signs of heart disease could be discovered. The electrocardiograms, however, revealed a pronounced prolongation of the QT interval in all cases. Three of the deaf-mute children died suddenly at the ages of 4, 5, and 9 years respectively."

Reproduced from Jervell A, Lange-Nielsen F: Congenital deaf mutism, functional heart disease with prolongation of the QT interval, and sudden death. Am Heart J 1957;54:59-68 with permission.

Lepeschkin and Surawicz described in 1952 QT interval differences among the 12 leads of the surface ECG as a possible expression of spatial inhomogeneity of ventricular repolarization (90). However, it lasted until the mid-80s until systematic investigations of the spatial inhomogeneity of repolarization were performed: Mirvis and colleagues studied the difference between the longest and shortest QT interval using body surface mapping in normals and patients after myocardial infarction (91). The term "QT dispersion" as an expression of regional differences in myocardial repolarization has been established in clinical cardiology by Ronald WF Campbell and coworkers (92). Even if in our days the relevance of the QT dispersion for clinical decision making is very limited owing to methodological problems and contradicting study results, it served as an important step for a better understanding of the spatial aspects of repolarization.

history of the "long qt syndrome" and "torsades de pointes" tachycardia

The long QT syndrome is characterized by QT interval prolongation and syncope or sudden cardiac death owing to ventricular tachyarrhythmias. The congenital form can either be familial or idiopathic (93,94). The familial type consists of two subgroups:

Fig. 10. Torsades de pointes tachycardia. Dessertenne first described this form of polymorphic tachycardia in 1966 when he observed this rhythm disorder in an 80-year old female patient with complete AV block (46).

1. The Jervell and Lange-Nielsen which is associated with deafness.

2. The Romano-Ward syndrome with normal hearing. Two classical descriptions of these functional, hereditary syncopal cardiac disorders exist (95-98).

Jervell and Lange-Nielsen Syndrome. In 1957 Anton Jervell and Fred Lange-Nielsen described a case of syncopal arrhythmia and QT prolongation combined with a profound congenital deafness in a Norwegian family with six children (95). Four of the children were deaf-mutes, suffered from syncopal episodes with loss of consciousness and demonstrated a clear QT interval prolongation on their surface electrocardiograms (Fig. 9). Three of the four children with the disease died suddenly. Interestingly the parents of those children were healthy as an indicator for the recessive genetics in the Jervell and Lange-Nielsen syndrome.

Romano-Ward Syndrome. Cesarino Romano was born in Voghera, Italy in 1924. After his study of medicine at the University of Pavia, he worked in pediatrics at the University of Genoa. In 1961 he became a professor for pediatrics and later he served as the director of the First Pediatric Department and the Scientific Institute of the Pediatric Clinics at the University of Genoa. Among numerous publications dealing with hereditary hypothyroidism, cystic fibrosis, and cardiac disorders, he described in 1963 an inherited functional syncopal heart disorder with prolonged QT interval in a 3-mo-old female patient

("Aritmie cardiache rare dell'eta'pediatrica") (96). Two brothers of his patient had exhibited the same symptoms and died suddenly at a young age. Independently of Romano, Owen Conor Ward, professor for clinical pediatrics at the University of Dublin, published one year later a work in Ireland entitled "A New Familial Cardiac Syndrome in Children." He also described syncopal attacks and a prolonged QT interval in both a young female patient and her brother (97). Ward was born in Monaghan, Ireland on August 27, 1923. After completing St. Macarten's College in Monaghan, Ward studied medicine at the University College of Dublin where he passed his examinations in 1947. After his internship in various Irish hospitals, Ward specialized in pediatric medicine in 1949 and earned his doctorate in 1951 with a thesis on hypoglycemia in neonates. After that, Ward worked for a few years in a Dublin pediatric clinic. In 1972, he was made a professor of clinical pediatrics at the University of Dublin, where he has served as first professor for pediatrics since 1983.

The typical arrhythmia of patients with congenital or acquired long QT syndrome is the torsades de pointes tachycardia. This specific form of a dangerous polymorphic ventricular tachyarrhythmia is characterized by a repetitive change of the main QRS vector during tachycardia in the presence of a prolonged repolarization. Dessertenne first described the torsades de pointes morphology in an 80-yr-old female patient with intermittent AV block (Fig. 10) (99). The cause of her recurring syncopal episodes was the torsades de pointes tachycardia rather than the bradycardia, as it has primarily been suspected. Dessertenne himself suggested in his description that two competing foci were responsible for the typical torsades de pointes morphology. This hypothesis has been tested in experimental animal studies, one using a porcine Langendorff heart technique by Christoph Naumann d'Alnoncourt and Berndt Lüderitz and in a canine heart in situ experiment from Gust H Bardy and Raymond E Idecker (100,101). In both studies pacing from the left and right ventricular site at a similar but periodically changing rate resulted in an electrocardiogram with torsades de pointes configuration.


1. Purkinje JE. Mikroskopisch-neurologische Beobachtungen. Arch Anat Physiol Wiss Med II/III:281-295.

2. Paladino G. Contribuzione all'Anatomia, Istologia e Fisilogia del Cuore. Napoli: Movim Med Chir, 1876.

3. His W Jr. Die Tätigkeit des embryonalen Herzens und deren Bedeutung für die Lehre von der Herzbewegung beim Erwachsenen. Arb Med Klin 1893;14-49.

4. Aschoff L, Tawara S. Die heutige Lehre von den pathologisch-anatomischen Grundlagen der Herzschwäche. Kritische Bemerkungen auf Grund eigener Untersuchungen. Jena, Fischer, 1906.

5. Wenckebach KF. Beiträge zur Kenntnis der menschlichen Herztätigkeit. Arch Anat Physiol 1906; 297-354.

6. Keith A, Flack M. The form and nature of the muscular connections between the primary divisions of the vertebrate heart. J Anat Physiol 1907;41:172-189.

7. Bachmann G. The inter-auricular time interval. Am J Physiol 1916;41:309-320.

8. Mahaim I. Kent fibers and the AV paraspecific conduction through the upper connections of the bundle of His-Tawara. Am Heart J 1947;33:651-653.

9. James TN. Morphology of the human atrioventricular node with remarks pertinent to its electrophysi-ology. Am Heart J 1961;62:756-771.

10. Hirsch A, ed. Biographisches Lexikon der hervorragenden Ärzte aller Zeiten und Völker. 3.Aufl. Bd. IV. München, Urban & Schwarzenberg, 1929.

11. Volavsek B, ed. Marko Gerbec. Marcus Gerbezius 1658-1718. Syndroma Gerbezius-Morgagni-Adams-Stokes. Ljubljana, 1977.

12. Cammilli L, Feruglio GA. Breve cronistoria della cardiostimolazione elettrica date, uomini e fatti da ricordare. Publicazione Distribuita in Occcasione des Secondo Simposio Europeo di Cardiostimolazione. Firenze, 3-6 Maggio, 1981.

13. Galvani L. De viribus electricitatis in motu musculari commentarius. Bologna Inst Sci, 1791.

14. Bichat MFX. Recherches physiologiques sur la vie et la mort. Paris, Fournier, 1804.

15. Aldini G. Essai theorique et experimental sur le galvanisme, avec une serie d'experiences faites en presence des commissaires de l'institut national de France, et en divers amphitheatres de Londres. Paris, Fournier, 1804.

16. Adams R. Cases of diseases of the heart accompanied with pathological observations. Dublin Hosp Rep 1827;4:353-453.

17. Stokes W. Observations of some cases of permanently slow pulse. Dublin Q J Med Sci 1846;2:73-85.

18. Duchenne de Bologne GBA. De l'ectrisation localisée et de son application à la pathologie et à la thérapeutique par courants induits et par courants galvaniques interrompus et continues. Paris, Bailliére, 1872.

19. von Ziemssen H. Studien über die Bewegungsvorgänge am menschlichen Herzen sowie über die mechanische und elektrische Erregbarkeit des Herzens und des Nervus phrenicus, angestellt an dem freiliegenden Herzen der Catharina Serafin. Arch Klin Med 1882;30:270-303.

20. Hyman AS. Resuscitation of the stopped heart by intracardial therapy. II. Experimental use of an artificial pacemaker. Arch Intern Med 1932;50:283-305.

21. Zoll PM. Resuscitation of heart in ventricular standstill by external electrical stimulation. N Engl J Med 1952;247:768-771.

22. Elmquist R, Senning A. An implantable pacemaker for the heart. In: Smyth CN, ed. Medical Electronics. Proceedings of the Second International Conference on Medical Electronics, Paris 1959. London, Iliffe & Sons, 1960.

23. Furman S, Robinson G. The use of an intracardiac pacemaker in the correction of total heart block. Surg Forum 1958;9:245-248.

24. Bouvrain Y, Zacouto F. L'entrainment électrosystolique du coeur. Presse Med 1961;69:525-528.

25. Lown B, Amarasingham R, Neumann J. New method for terminating cardiac arrhythmias. Use of synchronized capacitor discharge. JAMA 1962;182:548-555.

26. Berkovits BV, Castellanos A Jr, Lemberg L. Bifocal demand pacing. Circulation 1969;40(Suppl):III44.

27. Wellens HJJ. Electrical stimulation of the heart in the study and treatment of tachycardias. Leiden, Kroese, 1971.

28. Zipes DP, Fischer J, King RM, et al. Termination of ventricular fibrillation in dogs by depolarizing a critical amount of myocardium. Am J Cardiol 1975;36:37-44.

29. Josephson ME, Horowitz LN, Farshidi A, et al. Recurrent sustained ventricular tachycardia. Circulation 1978;57:431-440.

30. Mirowski M, Reid PR, Mower MM, et al. Termination of malignant ventricular arrhythmias with an implanted automatic defibrillator in human beings. New Engl J Med 1980;303:322-324.

31. Gallagher JJ, Svenson RH, Kasell JH, et al. Catheter technique for closed-chest ablation of the atrioventricular conduction system: A therapeutic alternative for the treatment of refractory supraventricular tachycardia. N Engl J Med 1982;306:194-200.

32. Scheinmann MM, Morady F, Hess DS, et al. Transvenous catheter technique for induction of damage to the atrioventricular junction in man. Am J Cardiol 1982;49:1013.

33. Lüderitz B, Naumann d'Alnoncourt C, Steinbeck G, et al. Therapeutic pacing in tachyarrhythmias by implanted pacemakers. PACE 1982;5:366-371.

34. Manz M, Gerckens U, Lüderitz B. Antitachycardia pacemaker (Tachylog) and automatic implantable defibrillator (AID): Combined use in ventricular tachyarrhythmias. Circulation 1985;72(Suppl):III383.

35. Borggrefe M, Budde T, Podczek A, et al. High frequency alternating current ablation of an accessory pathway in humans. J Am Coll Cardiol 1987;10:576-582.

36. Saksena S, Parsonnet V. Implantation of a cardioverter-defibrillator without thoracotomy using a triple electrode system. JAMA 1988;259:69-72.

37. Jackman WM, Wang X, Friday KJ, et al. Catheter ablation of accessory atrioventricular pathways (Wolff-Parkinson-White syndrome) by radiofrequency current. N Engl J Med 1991;324:1605-1611.

38. Kuck KH, Schlüter M, Geiger M, et al. Radiofrequency current catheter ablation of accessory pathways. Lancet 1991;337:1557-1561.

39. Daubert C, Gras D, Berder V, et al. Permanent atrial resynchronisation by syncronous bi-atrial pacing in the preventive treatment of atrial flutter associated with high degree interatrial block. Arch Mal Coeur Vaiss 1994;11:1535-1546

40. Cazeau S, Ritter P, Bakdach S, et al. Four chamber pacing in dilated cardiomyopathy. PACE 1994;17:1974-1979.

41. Lau CP, Tse HF, Lee K, et al. Initial clinical experience of a human implantable atrial defibrillator. PACE 1996;19:625.

42. Jung W, Lüderitz B. First worldwide implantation of an arrhythmia management system for ventricular and supraventricular tachyarrhythmias. Lancet 1997;349:853-854.

43. Haissaguerre M, Jais P, Shah DC, et al. Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins. N Engl J Med 1998;339:659-666.

44. Huang DT, Monahan KM, Zimetbaum P, et al. Hybrid pharmacologic and ablative therapy: a novel and effective approach for the management of atrial fibrillation. J Cardiovasc Electrophysiol 1999;9:462-469.

45. Waller AG. A demonstration on man of electromotive changes accompanying the heart's beat. J Physiol 1887;8:229-234.

46. Einthoven W. Ein neues Galvanometer. Ann Phys 1903;12:1059-1071.

47. Cremer M. Über die direkte Ableitung der Aktionsströme des menschlichen Herzens vom Oesophagus und über das Elektrokardiogramm des Fötus. Münch Med Wschr 1906;53:811-813.

48. Wilson FN, Johnston FD, MacLeod AG, Barker PS. Electrocardiograms that represent the potential variations of a single electrode. Am Heart J. 1933;9:447-458.

49. Schellong F, Heller S, Schwingel E. Das Vektorkardiogramm, eine Untersuchungsmethode des Herzens. I. Mitteilung Z Kreislaufforsch 1937;29:497.

50. Nehb W. Zur Standardisierung der Brustwandableitungen des Elektrokardiogramms. Klin Wochenschr 1938;17:1807.

51. Goldberger E. A simple indifferent, electrocardiographic electrode of zero potential and a technique of obtaining augmented unipolar, extremity leads. Am Heart J 1942;23:483-492.

52. Frank E. An accurate, clinically practical system for spatial vectorcardiography. Circulation 1956;13:737-749.

53. Giraud G, Puech P, Latour H, Hertault J. Variations de potentiel lieés à l'activité du système de conduction auricula-ventriculaire chez l'homme. Arch Mal Coeur 1960;53:757-776.

54. Scherlag BJ, Lau SH, Helfant RH, Berkowitz WD, Stein E, Damato AN. Catheter technique for recording His bundle activity in man. Circulation 1969;39:13-18.

55. Einthoven W. Über die Form des menschlichen Elektrocardiogramms. Arch f d Ges Physiol 1895;60:101-123.

56. Ader C. Sur un nouvel appareil enregistreur pour cables sous-marins. Compt Rend Acad Sci 1897;124:1440-1442.

57. Einthoven W. Galvanometrische registratie van het menschelijk electrocardiogram. In: Herinnerings-bundel Professor S.S. Rosenstein. Leiden: Eduard Ijdo.1902:101-107

58. Einthoven W. Die galvanometrische Registrierung des menschlichen Elektrokardiogramms, zugleich eine Beurteilung der Anwendung des Kapillar-Elektrometers in der Physiologie. Pflügers Arch 1903;99:472-480.

59. Einthoven W. The string galvanometer and the human electrocardiogram. Proc Kon Akademie voor Wetenschappen 1903;6:107-115.

60. Einhoven W. Le télécardiogramme. Arch Int de Physiol 1906;4:132-164.

61. Pardée HEB. Clinical aspects of the electrocardiogram. New York, London, Paul B Hoeber Inc, 1942, pp 32-76.

62. Lüderitz B. Über die Beziehung zwischen der Breite von QRS und der Form des ST-Stückes im menschlichen EKG. Arch f Kreislaufforsch 1939;5:223-238.

63. Forssmann W. Die Sondierung des rechten Herzens. Klin Wochenschr 1929;8:2085-2087.

64. Scherlag BJ, Lau SH, Helfant RH, et al. Catheter technique for recording His bundle activity in man. Circulation 1969;39:13-18.

65. Durrer D, Ross JP. Epicardial excitation of the ventricles in a patient with Wolff-Parkinson-White-Syndrome. Circulation 1967;35:15-21.

66. Wellens HJJ, Schuilenburg RM, Durrer D. Electrical stimulation of the heart in patients with ventricular tachycardia. Circulation 1972;46:216-226.

67. Gallagher JJ, Pritchett ELC, Sealy WC, et al. The preexcitation syndromes. Prog Cardiovasc Dis 1978;20:285-327.

68. Horowitz LN, Josephson ME, Farshidi A, et al. Recurrent sustained ventricular tachycardia: role of the electrophysiologic study in selection of antiarrhythmic regimens. Circulation 1978;58:986-997.

69. Burdon-Sanderson J, Page FJM. On the time-relations of the excitatory process in the ventricle of the heart of the frog. J Physiol 1882;2:385-412.

70. Schütz E. Einphasische Aktionsströme vom in situ durchbluteten Säugetierherzen. Z Biol 1932;92: 441-425.

71. Franz MR. Monophasic action potentials. Armonk, NY, Futura Publishing Co, 2000, pp 149-363.

72. Vaughan Williams EM. Classification of antiarrhythmic drugs. In: Sandoe E, Flensted-Jensen E, Olesen KH, eds. Cardiac Arrhythmias. Astra Södertälje, 1970, pp 449-469.

73. Gettes LS. The electrophysiologic effects of antiarrhythmic drugs. Am J Cardiol 1971;28:526-535.

74. Davis LD, Temte JV. Electrophysiological actions of lidocaine on canine ventricular muscle and Purkinje fibers. Circ Res 1969;24:639-655.

75. Bigger JT, Mandel WJ. Effect of lidocaine on the electrophysiological properties of ventricular muscle and Purkinje fibers. J Clin Invest 1970;49:63-77.

76. Task Force of the Working Group on Arrhythmias of the European Society of Cardiology. The Sicilian Gambit. Circulation 1991;84:1831-1851.

77. Lüderitz B. Herzrhythmusstörungen. 5. Aufl., Berlin Heidelberg New York, Springer-Verlag, 1998.

78. Hoff HE. The history of the refractory period: a neglected contribution of Felice Fontana. Yale J Biol Med 1942;14:635-672.

79. Marey EJ. Des excitations electriques due coeur. Physiologie Experimentale. Travaux du Labaratorie de M Marey. Paris, G. Masson, 1876;2:63-86.

80. Shapiro E. The electrocardiogram and the arrhythmias: historical insights. In: Mandel WJ, ed. Cardiac Arrhythmias: Their Mechanism, Diagnosis and Management. Philadelphia, J. B. Lippincott, 1980, pp 1-11.

81. Bazett HC. An analysis of the time-relations of electrocardiograms. Heart 1920;7:353-386.

82. Shipley RA, Hallaran WR. The four-lead electrocardiogram in two hundred normal men and women. Am Heart J 1936;11:325-329.

83. Fridericia LS. Die Systolendauer im Elektrokardiogramm bei normalen Menschen und bei Herzkranken. Acta Med Scand 1920;53:469-486.

84. Ashman R. The normal duration of the QT interval. Am Heart J 1942;23:522-533.

85. Adams W. The normal duration of the electrocardiographic ventricular complex. J Clin Invest 1936;15:335-342.

86. Ljung O. A simple formula for clinical interpretation of the QT interval. Acta Med Scand 1949;134: 79-86.

87. Schlamowitz I. An analysis of the time relationship within the cardiac cycle in electrocardiograms of normal men. Am Heart J 1946;31:329-342.

88. Simonson E, Cady LD, Woodbury M. The normal QT interval. Am Heart J 1962:63:747-753.

89. Gouaux JL, Ashman R. Auricular fibrillation with aberration simulating ventricular paroxysmal tachycardia. Am Heart J 1947;34:366.

90. Lepeschkin E, Surawicz B. The measurement of the QT interval of the electrocardiogram. Circulation 1952;6:378-388.

91. Mirvis DM. Spatial variation of QT intervals in normal persons and patients with acute myocardial infarction. J Am Coll Cardiol 1985;5:625-631.

92. Day CP, McComb JM, Campbell RWF. QT-dispersion: an indication of arrhythmia risk in patients with long QT intervals. Br Heart J 1990;63:342-344.

93. Jackman WM, Friday KJ, Anderson JL, et al. The long QT syndromes: a critical review, new clinical observations and a unifying hypothesis. Prog Cardiovasc Dis 1988;31:118-172.

94. Roden DM, Spooner PN. Inherited long QT syndrome: a paradigm for understanding arrhythmogenesis. J Cardiovasc Electrophysiol 1999;10:1664-1683.

95. Jervell A, Lange-Nielsen F. Congenital deaf mutism, functional heart disease with prolongation of the QT interval, and sudden death. Am Heart J 1957;54:59-68.

96. Romano C, Gemme G, Pongiglione R. Aritmie cardiache rare dell'eta' pediatrica. Clin Pediatr 1963;45:656-683.

97. Ward OC. A new familial cardiac syndrome in children. J Irish Med Assoc 1964;54:103-107.

98. Lüderitz B. History of the Disorders of Cardiac Rhythm. Armonk, NY, Futura, 1998.

99. Dessertenne F. La Tachycardie ventriculaire a deux foyers opposes variables. Arch Mal Couer 1966;59:263-272.

100. Naumann d'Alnoncourt C, Zierhut W, Lüderitz B. "Torsade de pointes" tachycardia: reentry or focal activity? Br Heart J 1982;48:213-216.

101. Bardy GH, Ungerleider RM, Smith WM, et al. A mechanism of torsades de pointes in a canine model. Circulation 1983;67:52-59.

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