- Email: [email protected]
Torsades de pointes: twisting of the points or confusion of the points?
427
MCd Actuelle 1978: 5: 119-122. 26 Box E. Coeur et drogues psychotropes. 21 Scarlovsky S, Lewin RF, Kracoff 0, Strasberg B, Arditti A. Agmon J. Amiodarone-induced polymorphous ventricular tachycardia. Am Heart J 1983. 105: 6-12. 28 Surawicz K, Knoebel SB. Long QT: good, bad or indifferent? J Am Co11 Cardiol 1984; 4: 398-413. 29 Zilcher H, Glogar D, Kaindl F. Torsades de pointes: occurrence in myocardial ischaemia as a separate entity. Multiform ventricular tachycardia or not? Eur Heart J 1980: 1: 63. 30 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. 31 Schwartz PJ, Periti M. Malliani A. The long QT syndrome. Am Heart J 1975; 89: 378-390. 32 Dalle X. Meltzer E. Kravitz B. A new look at ventricular tachycardia. Acta Cardiol 1967; 22: 519. 33 Mallion JM, Avezou F, Denis B, Yalloub M, Martin-Noel P. Syndrome de QT long avec torsades de pointes, syncopes et insuffisance coronarienne. Arch Ma1 Coeur 1972; 65: 1209-1214. 34 Horowitz LN, Greenspan AM. Spielman SR. Josephson ME. Torsades de pointes: electrophysiologic studies in patients without transient pharmacologic or metabolic abnormalities. Circulation 1981; 63: 1120-1128. 35 Taylor GJ. Crampton RS. Gibson RS, Stebbins PT. Waldman MTG, Belier GA. Prolonged QT interval at onset of acute myocardial infarction in predicting early phase ventricular tachycardia. Am Heart J 1981; 102: 16-24. 36 Schwartz, PJ, Wolf S. QT interval prolongation as predictor of sudden death in patients with myocardial infarction. Circulation 1978; 57: 1074-1077. 37 Wellens HJJ. FarrC J, Bar FW. Ventricular tachycardia: value and limitations of stimulation studies. In: Narula AS,. ed. Cardiac arrhythmias. Electrophysiology, diagnosis and management. Baltimore: Williams and Wilkins, 1979; 436-456. 38 Scheinman MM. Morady F, Shen EN. Shapiro WA. Role of electrophysiologic testing. In: L&y S. Scheinman MM, eds. Patients with ventricular tachycardia in cardiac arrhythmias. From diagnosis to therapy. Mount Kisco. NY: Futura Publishing. 1984; 421-430.
IJC 0240B
Torsades de pointes: twisting of the points or confusion of the points? * (Key word: torsades
de pointes)
The debate over the torsades de pointes reminds this writer of the currently popular American television commercial in which retired athletes argue the attributes of a particular beverage. They all agree to the excellence of the brew but is it because it “tastes better” or is it “less filling”! We all know very well what torsades de pointes is but - is it “torsades de pointes” [2] or “torsade de pointes” [3] or “ torsade de pointe” [4] or “ torsades de pointes” [5]? Is it “comporte toujours . . . par une prolongation de I’espace QT” [5] or can it occur without QT interval prolongation [6]? The initial question - the spelling - is trivial but annoying particularly when * From the Division of Clinical Cardiac mann
University
and Hospital.
Philadelphia.
Electrophysiology. Pennsylvania.
Internalional Journal of Cardioloa, 7 (1985) 427-430 I! Elsevier Science Publishers B.V. (Biomedical Division)
Likoff
Cardiovascular
Institute,
Hahne-
428
preparing a bibliography on the subject. For uniformity if nothing else, I suggest we defer to Dessertenne who initially used the term “ torsades de pointes” [l]. Although as Dessertenne acknowledged he was not the first to describe this peculiar form of “ tachycardie ventriculaire”, the euphonious French phrase [3] with its vivid imagery has caught the popular cardiologic imagination and appears destined to remain part of both French and English medical jargon. When faced with the choice between “ torsades de pointes” and such alternatives as ‘I transient ventricular fibrillation” [7], “paroxysmal ventricular fibrillation” [8], “transient recurrent ventricular fibrillation” [9], “pseudofibrillation” [lo], “cardiac ballet” [ll], “atypical ventricular tachycardia” “ventricular fibrillo-flutter” [13] and “polymorphous ventricular tachycardia” ]121. [14] physicians (if not grammarians) have embraced the former. Now we must focus on the more problematic issues - what is torsades de pointes and can it occur in the presence of a normal QT interval? In Dessertenne’s original description [l] the QT interval was not stressed and in fact, the morphologic characteristics of the tachycardia were highlighted. Neither, in fact, did earlier authors stress QT prolongation in describing this phenomenon [7]. However, following the christening of this particular form of ventricular tachycardia, subsequent articles enumerated diagnostic criteria and emphasized “ troubles de la repolarisation . . . prolongation de l’espace QT ou QU atteignant ou depassant 60/100 de seconde, l’onde T Ctant gtneralement Clargie et de tres grande amplitude” (“abnormalities of repolarization . . prolongation of the QT or QU interval attaining or exceeding 0.60 set, the T wave being generally large and of great amplitude”) [2]. Other authors have been less stringent and have suggested that repolarization abnormalities are typically present but are not obligatory [3,15-171. Certainly, even some investigators who were authors of these initial articles have subsequently published examples of torsades de pointes occurring in the presence of normal QT intervals [6,18]. We, however, miss the point, I think, if we fixate on the QT. Dessertenne obviously gave a descriptive appellation to a morphologic pattern - “par son aspect morphologique Cvocateur en torsades de pointes” [2] and he did this very well. The periodic bursts of continuously and cyclically varying QRS complexes - diminishing gradually to a nadir and increasing thereafter to inscribe a sine wave-like pattern is perfectly described by “ torsades de pointes”. Other names have been applied to this particular morphologic pattern of ventricular tachycardia but they are flawed. Polymorphous(ic) ventricular tachycardia means VT having or occurring in many forms but does not convey the image of a continuously varying pattern. Transient ventricular fibrillation, pseudo-fibrillation etc. fall even further from the mark as the morphologic features of this rhythm do not resemble the unbridled chaos of fibrillation. The more colorful terms such as “cardiac ballet”, although linguistically interesting, add nothing to the descriptive aspect of electrocardiographic nomenclature. Thus Dessertenne created a perfect (or nearly so) name for this characteristic arrhythmia. If that is the case then what does it matter whether the QT is normal or prolonged. The clinical setting and etiology generally do not alter how we identify an arrhythmia. Do we not call an arrhythmia that is morphologically atria1 fibrillation
429
that, whether it occurs in the setting of hyperthyroidism or severe rheumatic mitral stenosis? Do we not call an arrhythmia that is morphologically ventricular fibrillation just that. whether it occurs in the setting of acute myocardial infarction or electrocution? It seems that an arrhythmia’s name is dictated by its appearance, rather than the clinical setting in which it occurs. “son aspect morphologique”, Finally we have a nosologic non sequitur - torsades de pointes can appear as a uniform QRS morphology tachycardia particularly during prolonged episodes [1.19] _ but then where is the twisting of the points? This is like fibrillation without fibrillatory waves! If torsades de pointes can appear at times “sans torsades” (i.e. uniform morphology ventricular tachycardia) then certainly it can sometimes appear without a concomitant long QT interval. If it cannot, what are we to call this arrhythmia when it occurs in a patient with a normal QT interval? I do not mean to dismiss lightly the obvious advantage of considering torsades de pointes as a circumscribed and inviolate syndrome. Cardiologists have learned to recognize a syndrome and to direct treatment toward removing known causes and instituting palliative procedures such as pacing. However, is that much lost? Is it not clear to the well trained physician who deals with cardiac rhythm disorders that torsades de pointes with QT prolongation is generally related to marked bradyarrhythmias, certain drugs and/or electrolyte disorders [20] but that a morphologically similar arrhythmia can occur without QT prolongation and may represent other etiologic and therapeutic possibilities? Furthermore, cannot a uniform morphology tachycardia be caused by the same mechanisms which can result in torsades de pointes and in these cases appropriate treatment is the same as that for “classic” torsades de pointes. Thus nosology does not guarantee appropriate therapy ~ understanding disease processes, mechanism of arrhythmias and the correct application of therapeutic alternatives afford the desired result. Torsades de pointes has assumed an important role in clinical arrhythmology. It has very descriptively named a characteristic ventricular tachycardia and provoked considerable study. The difference regarding points of view on torsades de pointes are now largely semantic. For my own part I prefer the name be attached to the morphologic pattern of this distinctive arrhythmia because it is so descriptive. The issue, however, should be resolved by consensus and eventual convention. This should allow more focused studies and understanding of ventricular tachyarrhythmias in general.
just
Division of Clinical Cardiac Electrophysiology Likoff Cardiovascular Institute Hahnemann University and Hospital Broad and Vine Streets Philadelphia, PA 19102.U.S.A.
Leonard
N.Horowitz
References 1 Dessertenne F. La tachycardie 59: 263-212.
ventriculaire
g deux foyers opposes
variables.
Arch Ma1 Coeur
1966:
430
2 Matte. G. Coumel Ph, Abitol G. Dessertenne F, Slama R. Le syndrome QT long et syncopes par torsades de pointes. Arch Ma1 Coeur 1970; 63: 831-853. 3 Krikler DM. Curry PVL. Torsade de pointes. an atypical ventricular tachycardia. Br Heart J 1976; 38: 117-120. 4 Oury M. Le phtnomtne de torsade de pointe. Rev MCd Liege 1973; 28: 221-227. 5 Slama R. Matte G, Coumel P, Dessertenne F. Le syndrome allongement de QT et syncopes par torsades de pointes. Lava1 MCd 1971; 42: 353-366. 6 Coumel Ph. LeClercq JF, Rosengarten M, Attuel P. Milosevic D. Unusual forms of severe ventricular tachyarrhythmias: their relationships with the QT interval and the vago-sympathetic balance. In: Kulbertus HE, Wellens HJJ. eds. Sudden death. The Hague: Martinus Nijhoff Publishers. 1980; 199-215. 7 Schwartz SP. Transient ventricular fibrillation. A study of the fibrillatory process in man. J Mt Sinai Hosp 1942; 8: 1005-1014. 8 Loeb HS. Pietras RJ, Gunnar RM, Tobin JR. Paroxysmal ventricular fibrillation in two patients with hypomagnesemia. Treatment by transvenous pacing. Circulation 1968; 37: 210-215. 9 Tamura K. Tamura T. Yoshida S, Inul M, Fukuhara N. Transient recurrent ventricular fibrillation due to hypopotassemia with special note on the U wave. Jpn Heart J 1967; 8: 652-660. 10 MacWilliam JA. Some applications of physiology to medicine. 11. Ventricular fibrillation and sudden death. Br Med J 1923; 2: 215-219. 11 Smirk FH, Ng J. Cardiac ballet: repetitions of complex electrocardiographic patterns. Br Heart J 1969; 31: 426-434. 12 Krikler DM, Curry PVL. Torsade de pointes, an atypical ventricular tachycardia. Br Heart J 1976; 38: 117-120. 13 Ranquin R, Parizel G. Ventricular fibrillo-flutter (torsade de pointes): an established electrocardiographic and clinical entity. Angiology 1977; 28: 115-118. 14 Sclaruvsky S, Strasberg B, Lewin RF, Agmon J. Polymorphous ventricular tachycardia: clinical features and treatment. Am J Cardiol 1979; 44: 339-344. 15 Touboul P. Torsade de pointes. In: Surawicz B, Reddy CP, Prystowsky EN, eds. Tachycardias. Boston: Martinus Nijhoff Publishing, 1984; 229-235. 16 Smith WM, Gallagher JJ. “Les torsades de pointes”: an unusual ventricular arrhythmia. Ann Intern Med 1980; 93: 578-584. 17 Zilcher H. Glogar D, Kaindl F. Torsades de pointes: occurrence in myocardial ischemia as a separate entity. Multiform ventricular tachycardia or not? Eur Heart J 1980; 1: 63-71. 18 Coumel P, Cauchemez B, Maisonblanche P. Ca-induced, verapamil-sensitive torsade de pointes with a short coupling interval. A specifically calcium-related arrhythmia? Eur Heart J 1984; 5: 261. 19 Krikler D. Ventricular tachycardia as part of unusual syndromes: a review. In: Sandoe E, ed. Management of ventricular tachycardia - role of mexiletine. Amsterdam/Oxford: Excerpta Medica, 1978; 401-408. 20 Fontaine G, Frank R, Grosgogeat Y. Torsades Cardiovasc Dis 1982: 51: 103-108.
de pointes:
definition
and management.
Mod Concepts
MCd Actuelle 1978: 5: 119-122. 26 Box E. Coeur et drogues psychotropes. 21 Scarlovsky S, Lewin RF, Kracoff 0, Strasberg B, Arditti A. Agmon J. Amiodarone-induced polymorphous ventricular tachycardia. Am Heart J 1983. 105: 6-12. 28 Surawicz K, Knoebel SB. Long QT: good, bad or indifferent? J Am Co11 Cardiol 1984; 4: 398-413. 29 Zilcher H, Glogar D, Kaindl F. Torsades de pointes: occurrence in myocardial ischaemia as a separate entity. Multiform ventricular tachycardia or not? Eur Heart J 1980: 1: 63. 30 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. 31 Schwartz PJ, Periti M. Malliani A. The long QT syndrome. Am Heart J 1975; 89: 378-390. 32 Dalle X. Meltzer E. Kravitz B. A new look at ventricular tachycardia. Acta Cardiol 1967; 22: 519. 33 Mallion JM, Avezou F, Denis B, Yalloub M, Martin-Noel P. Syndrome de QT long avec torsades de pointes, syncopes et insuffisance coronarienne. Arch Ma1 Coeur 1972; 65: 1209-1214. 34 Horowitz LN, Greenspan AM. Spielman SR. Josephson ME. Torsades de pointes: electrophysiologic studies in patients without transient pharmacologic or metabolic abnormalities. Circulation 1981; 63: 1120-1128. 35 Taylor GJ. Crampton RS. Gibson RS, Stebbins PT. Waldman MTG, Belier GA. Prolonged QT interval at onset of acute myocardial infarction in predicting early phase ventricular tachycardia. Am Heart J 1981; 102: 16-24. 36 Schwartz, PJ, Wolf S. QT interval prolongation as predictor of sudden death in patients with myocardial infarction. Circulation 1978; 57: 1074-1077. 37 Wellens HJJ. FarrC J, Bar FW. Ventricular tachycardia: value and limitations of stimulation studies. In: Narula AS,. ed. Cardiac arrhythmias. Electrophysiology, diagnosis and management. Baltimore: Williams and Wilkins, 1979; 436-456. 38 Scheinman MM. Morady F, Shen EN. Shapiro WA. Role of electrophysiologic testing. In: L&y S. Scheinman MM, eds. Patients with ventricular tachycardia in cardiac arrhythmias. From diagnosis to therapy. Mount Kisco. NY: Futura Publishing. 1984; 421-430.
IJC 0240B
Torsades de pointes: twisting of the points or confusion of the points? * (Key word: torsades
de pointes)
The debate over the torsades de pointes reminds this writer of the currently popular American television commercial in which retired athletes argue the attributes of a particular beverage. They all agree to the excellence of the brew but is it because it “tastes better” or is it “less filling”! We all know very well what torsades de pointes is but - is it “torsades de pointes” [2] or “torsade de pointes” [3] or “ torsade de pointe” [4] or “ torsades de pointes” [5]? Is it “comporte toujours . . . par une prolongation de I’espace QT” [5] or can it occur without QT interval prolongation [6]? The initial question - the spelling - is trivial but annoying particularly when * From the Division of Clinical Cardiac mann
University
and Hospital.
Philadelphia.
Electrophysiology. Pennsylvania.
Internalional Journal of Cardioloa, 7 (1985) 427-430 I! Elsevier Science Publishers B.V. (Biomedical Division)
Likoff
Cardiovascular
Institute,
Hahne-
428
preparing a bibliography on the subject. For uniformity if nothing else, I suggest we defer to Dessertenne who initially used the term “ torsades de pointes” [l]. Although as Dessertenne acknowledged he was not the first to describe this peculiar form of “ tachycardie ventriculaire”, the euphonious French phrase [3] with its vivid imagery has caught the popular cardiologic imagination and appears destined to remain part of both French and English medical jargon. When faced with the choice between “ torsades de pointes” and such alternatives as ‘I transient ventricular fibrillation” [7], “paroxysmal ventricular fibrillation” [8], “transient recurrent ventricular fibrillation” [9], “pseudofibrillation” [lo], “cardiac ballet” [ll], “atypical ventricular tachycardia” “ventricular fibrillo-flutter” [13] and “polymorphous ventricular tachycardia” ]121. [14] physicians (if not grammarians) have embraced the former. Now we must focus on the more problematic issues - what is torsades de pointes and can it occur in the presence of a normal QT interval? In Dessertenne’s original description [l] the QT interval was not stressed and in fact, the morphologic characteristics of the tachycardia were highlighted. Neither, in fact, did earlier authors stress QT prolongation in describing this phenomenon [7]. However, following the christening of this particular form of ventricular tachycardia, subsequent articles enumerated diagnostic criteria and emphasized “ troubles de la repolarisation . . . prolongation de l’espace QT ou QU atteignant ou depassant 60/100 de seconde, l’onde T Ctant gtneralement Clargie et de tres grande amplitude” (“abnormalities of repolarization . . prolongation of the QT or QU interval attaining or exceeding 0.60 set, the T wave being generally large and of great amplitude”) [2]. Other authors have been less stringent and have suggested that repolarization abnormalities are typically present but are not obligatory [3,15-171. Certainly, even some investigators who were authors of these initial articles have subsequently published examples of torsades de pointes occurring in the presence of normal QT intervals [6,18]. We, however, miss the point, I think, if we fixate on the QT. Dessertenne obviously gave a descriptive appellation to a morphologic pattern - “par son aspect morphologique Cvocateur en torsades de pointes” [2] and he did this very well. The periodic bursts of continuously and cyclically varying QRS complexes - diminishing gradually to a nadir and increasing thereafter to inscribe a sine wave-like pattern is perfectly described by “ torsades de pointes”. Other names have been applied to this particular morphologic pattern of ventricular tachycardia but they are flawed. Polymorphous(ic) ventricular tachycardia means VT having or occurring in many forms but does not convey the image of a continuously varying pattern. Transient ventricular fibrillation, pseudo-fibrillation etc. fall even further from the mark as the morphologic features of this rhythm do not resemble the unbridled chaos of fibrillation. The more colorful terms such as “cardiac ballet”, although linguistically interesting, add nothing to the descriptive aspect of electrocardiographic nomenclature. Thus Dessertenne created a perfect (or nearly so) name for this characteristic arrhythmia. If that is the case then what does it matter whether the QT is normal or prolonged. The clinical setting and etiology generally do not alter how we identify an arrhythmia. Do we not call an arrhythmia that is morphologically atria1 fibrillation
429
that, whether it occurs in the setting of hyperthyroidism or severe rheumatic mitral stenosis? Do we not call an arrhythmia that is morphologically ventricular fibrillation just that. whether it occurs in the setting of acute myocardial infarction or electrocution? It seems that an arrhythmia’s name is dictated by its appearance, rather than the clinical setting in which it occurs. “son aspect morphologique”, Finally we have a nosologic non sequitur - torsades de pointes can appear as a uniform QRS morphology tachycardia particularly during prolonged episodes [1.19] _ but then where is the twisting of the points? This is like fibrillation without fibrillatory waves! If torsades de pointes can appear at times “sans torsades” (i.e. uniform morphology ventricular tachycardia) then certainly it can sometimes appear without a concomitant long QT interval. If it cannot, what are we to call this arrhythmia when it occurs in a patient with a normal QT interval? I do not mean to dismiss lightly the obvious advantage of considering torsades de pointes as a circumscribed and inviolate syndrome. Cardiologists have learned to recognize a syndrome and to direct treatment toward removing known causes and instituting palliative procedures such as pacing. However, is that much lost? Is it not clear to the well trained physician who deals with cardiac rhythm disorders that torsades de pointes with QT prolongation is generally related to marked bradyarrhythmias, certain drugs and/or electrolyte disorders [20] but that a morphologically similar arrhythmia can occur without QT prolongation and may represent other etiologic and therapeutic possibilities? Furthermore, cannot a uniform morphology tachycardia be caused by the same mechanisms which can result in torsades de pointes and in these cases appropriate treatment is the same as that for “classic” torsades de pointes. Thus nosology does not guarantee appropriate therapy ~ understanding disease processes, mechanism of arrhythmias and the correct application of therapeutic alternatives afford the desired result. Torsades de pointes has assumed an important role in clinical arrhythmology. It has very descriptively named a characteristic ventricular tachycardia and provoked considerable study. The difference regarding points of view on torsades de pointes are now largely semantic. For my own part I prefer the name be attached to the morphologic pattern of this distinctive arrhythmia because it is so descriptive. The issue, however, should be resolved by consensus and eventual convention. This should allow more focused studies and understanding of ventricular tachyarrhythmias in general.
just
Division of Clinical Cardiac Electrophysiology Likoff Cardiovascular Institute Hahnemann University and Hospital Broad and Vine Streets Philadelphia, PA 19102.U.S.A.
Leonard
N.Horowitz
References 1 Dessertenne F. La tachycardie 59: 263-212.
ventriculaire
g deux foyers opposes
variables.
Arch Ma1 Coeur
1966:
430
2 Matte. G. Coumel Ph, Abitol G. Dessertenne F, Slama R. Le syndrome QT long et syncopes par torsades de pointes. Arch Ma1 Coeur 1970; 63: 831-853. 3 Krikler DM. Curry PVL. Torsade de pointes. an atypical ventricular tachycardia. Br Heart J 1976; 38: 117-120. 4 Oury M. Le phtnomtne de torsade de pointe. Rev MCd Liege 1973; 28: 221-227. 5 Slama R. Matte G, Coumel P, Dessertenne F. Le syndrome allongement de QT et syncopes par torsades de pointes. Lava1 MCd 1971; 42: 353-366. 6 Coumel Ph. LeClercq JF, Rosengarten M, Attuel P. Milosevic D. Unusual forms of severe ventricular tachyarrhythmias: their relationships with the QT interval and the vago-sympathetic balance. In: Kulbertus HE, Wellens HJJ. eds. Sudden death. The Hague: Martinus Nijhoff Publishers. 1980; 199-215. 7 Schwartz SP. Transient ventricular fibrillation. A study of the fibrillatory process in man. J Mt Sinai Hosp 1942; 8: 1005-1014. 8 Loeb HS. Pietras RJ, Gunnar RM, Tobin JR. Paroxysmal ventricular fibrillation in two patients with hypomagnesemia. Treatment by transvenous pacing. Circulation 1968; 37: 210-215. 9 Tamura K. Tamura T. Yoshida S, Inul M, Fukuhara N. Transient recurrent ventricular fibrillation due to hypopotassemia with special note on the U wave. Jpn Heart J 1967; 8: 652-660. 10 MacWilliam JA. Some applications of physiology to medicine. 11. Ventricular fibrillation and sudden death. Br Med J 1923; 2: 215-219. 11 Smirk FH, Ng J. Cardiac ballet: repetitions of complex electrocardiographic patterns. Br Heart J 1969; 31: 426-434. 12 Krikler DM, Curry PVL. Torsade de pointes, an atypical ventricular tachycardia. Br Heart J 1976; 38: 117-120. 13 Ranquin R, Parizel G. Ventricular fibrillo-flutter (torsade de pointes): an established electrocardiographic and clinical entity. Angiology 1977; 28: 115-118. 14 Sclaruvsky S, Strasberg B, Lewin RF, Agmon J. Polymorphous ventricular tachycardia: clinical features and treatment. Am J Cardiol 1979; 44: 339-344. 15 Touboul P. Torsade de pointes. In: Surawicz B, Reddy CP, Prystowsky EN, eds. Tachycardias. Boston: Martinus Nijhoff Publishing, 1984; 229-235. 16 Smith WM, Gallagher JJ. “Les torsades de pointes”: an unusual ventricular arrhythmia. Ann Intern Med 1980; 93: 578-584. 17 Zilcher H. Glogar D, Kaindl F. Torsades de pointes: occurrence in myocardial ischemia as a separate entity. Multiform ventricular tachycardia or not? Eur Heart J 1980; 1: 63-71. 18 Coumel P, Cauchemez B, Maisonblanche P. Ca-induced, verapamil-sensitive torsade de pointes with a short coupling interval. A specifically calcium-related arrhythmia? Eur Heart J 1984; 5: 261. 19 Krikler D. Ventricular tachycardia as part of unusual syndromes: a review. In: Sandoe E, ed. Management of ventricular tachycardia - role of mexiletine. Amsterdam/Oxford: Excerpta Medica, 1978; 401-408. 20 Fontaine G, Frank R, Grosgogeat Y. Torsades Cardiovasc Dis 1982: 51: 103-108.
de pointes:
definition
and management.
Mod Concepts