Torsade de Pointes

This is part of: Ventricular Arrhythmias

Torsade de Pointes (TdP)
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Atrial rate	60-100 bpm
Ventricular rate	150-300 bpm
Regularity	regular
Origin	ventricles
P-wave	AV-dissociation
Effect of adenosine	no rate reduction (sometimes accelerates)
Example ECG: Initiation of Torsade de Pointes (TdP) by a short-long-short sequence
Example ECG2: {{{example2}}}

Torsade de pointes is a ventricular tachycardia associated with a long QT time on the resting ECG. Torsade de pointes is typically initiated by a short-long-short interval. A ventricle extrasystole (first beat: short) is followed by a compensatory pause. The following beat (second beat: long) has a longer QT interval. If the next beat follows shortly thereafter, ther is a good chance that this third beat falls within the QT interval, resulting in the R on T phenomenon and subsequent Torsades de pointes. During Torsades de pointes the ventricles depolarize in a circular fashion resulting in QRS complexes with a continuously turning heart axis around the baseline (hence the name Torsade de Pointes). Read the chapter on the Long QT Syndrome for an list of causes.

Treatment[1]

• Withdrawal of any offending drugs and correction of electrolyte abnormalities (potassium repletion up to 4.5 to 5 mmol/liter).
• Acute and long-term cardiac pacing in patients with TdP presenting with heart block and symptomatic bradycardia.[2]
• Intravenous magnesium sulfate for patients with QT prolongation and few episodes of TdP.
• Acute and long-term cardiac pacing for patients who have recurrent, pause-dependent TdP.
• Beta blockers combined with cardiac pacing as acute therapy for patients with TdP and sinus bradycardia.
• Isoproterenol as temporary treatment in patients with recurrent pause-dependent TdP who do not have congenital long QT syndrome.

There has been much debate in the Circulation journal among French and American scientist whether one should write Torsades de Pointes or Torsade de Pointes. As for now Torsade is prefered (unless one sees rotations around more than one axis in one episode), but both forms are used in similar frequency.[3]

Examples

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  A twelve lead registration of Torsade de pointes. Reprinted with permission Copyright 2001 Texas Heart Institute [4]

References

1. Zipes DP, Camm AJ, Borggrefe M, Buxton AE, Chaitman B, Fromer M, Gregoratos G, Klein G, Moss AJ, Myerburg RJ, Priori SG, Quinones MA, Roden DM, Silka MJ, Tracy C, Blanc JJ, Budaj A, Dean V, Deckers JW, Despres C, Dickstein K, Lekakis J, McGregor K, Metra M, Morais J, Osterspey A, Tamargo JL, Zamorano JL, Smith SC Jr, Jacobs AK, Adams CD, Antman EM, Anderson JL, Hunt SA, Halperin JL, Nishimura R, Ornato JP, Page RL, Riegel B, American College of Cardiology/American Heart Association Task Force, European Society of Cardiology Committee for Practice Guidelines, and European Heart Rhythm Association and the Heart Rhythm Society. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death--executive summary: A report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death) Developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society. Eur Heart J. 2006 Sep;27(17):2099-140. DOI:10.1093/eurheartj/ehl199 |
2. Eldar M, Griffin JC, Abbott JA, Benditt D, Bhandari A, Herre JM, Benson DW, and Scheinman MM. Permanent cardiac pacing in patients with the long QT syndrome. J Am Coll Cardiol. 1987 Sep;10(3):600-7. DOI:10.1016/s0735-1097(87)80203-6 |
3. Moise NS. As Americans, we should get this right. Circulation. 1999 Sep 28;100(13):1462. DOI:10.1161/01.cir.100.13.1462 |
4. Khan IA. Twelve-lead electrocardiogram of torsades de pointes. Tex Heart Inst J. 2001;28(1):69.