Torsade de pointes
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
| Torsade de pointes Classification and external resources | |
 | |
|---|---|
| DiseasesDB | 29252 |
| eMedicine | med/2286 emerg/596 |
| MeSH | D016171 |
| Cardiology Network |
 Discuss Torsade de pointes further in the WikiDoc Cardiology Network |
| Adult Congenital |
|---|
| Biomarkers |
| Cardiac Rehabilitation |
| Congestive Heart Failure |
| CT Angiography |
| Echocardiography |
| Electrophysiology |
| Cardiology General |
| Genetics |
| Health Economics |
| Hypertension |
| Interventional Cardiology |
| MRI |
| Nuclear Cardiology |
| Peripheral Arterial Disease |
| Prevention |
| Public Policy |
| Pulmonary Embolism |
| Stable Angina |
| Valvular Heart Disease |
| Vascular Medicine |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Phone:617-632-7753
Associate Editor-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]
Please Join in Editing This Page and Apply to be an Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [3] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.
Overview
Torsade de pointes or torsades is a French term that literally means "twisting of the points" 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 Torsade de pointes. During Torsade 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.
Also, a more rare form of short coupled Torsade de pointes has been observed.[1]
History
It was first described by Dessertenne in 1966[2] and refers to a specific variety of ventricular tachycardia that exhibits distinct characteristics on the electrocardiogram (ECG).
Terminology
The French term is largely due to the fact that the phenomenon was originally described in a French medical journal by Dessertenne in 1966, when he observed this rhythm disorder in an 80-year-old female patient with complete intermittent atrioventricular block.
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]
Presentation
Torsades is a rapid, polymorphic ventricular tachycardia with a characteristic twist of the QRS complex around the isoelectric baseline. It is also associated with a fall in arterial blood pressure, which gives rise to the syncopal symptoms experienced by patients.
Although torsade de pointes is a rare ventricular arrhythmia, it can degenerate into ventricular fibrillation, which will lead to sudden death in the absence of medical intervention. Torsade de pointes is associated with Long QT syndrome, a condition whereby prolonged QT intervals are visible on the ECG.
Causes
Long QT syndrome can either be inherited as congenital mutations of ion channels carrying the cardiac impulse/action potential or acquired as a result of drugs that block these cardiac ion currents.
Common causes for torsades de pointes include hypomagnesemia and hypokalemia. It is commonly seen in malnourished individuals and chronic alcoholics. Drug interactions such as erythromycin or Avelox, taken concomitantly with inhibitors like nitroimidazole, Diarrhea, dietary supplements, and various medications like methadone, Lithium, tricyclic antidepressants or phenothiazines may also contribute.
Factors that are associated with an increased tendency toward torsades de pointes include:
- Familial long QT syndrome
- Class IA antiarrhythmics
- Hypomagnesemia
- Hypokalemia
- Hypoxia
- Acidosis
- Heart failure
- Left ventricular hypertrophy
- Slow heart rate
- Female gender
The List of Drugs that Causing Torsades de pointes
Drugs that are generally accepted to have a risk of causing torsades de pointes
- Amiodarone
- Arsenic trioxide
- Astemizole
- Bepridil
- Chloroquine
- Chlorpromazine
- Cisapride
- Clarithromycin
- Disopyramide
- Dofetilide
- Domperidone
- Droperidol
- Erythromycin
- Halofantrine
- Haloperidol
- Ibutilide
- Levomethadyl
- Mesoridazine
- Methadone
- Pentamidine
- Pimozide
- Probucol
- Procainamide
- Quinidine
- Sotalol
- Sparfloxacin
- Terfenadine
- Thioridazine
The List of Drugs that Possible Causing Torsades de pointes
Drugs that in some reports have been associated with torsades de pointes and/or QT prolongation but at this time lack substantial evidence for causing torsades de pointes.
- Alfuzosin
- Amantadine
- Atazanavir
- Azithromycin
- Chloral hydrate
- Clozapine
- Dolasetron
- Felbamate
- Flecainide
- Foscarnet
- Fosphenytoin
- Gatifloxacin
- Gemifloxacin
- Granisetron
- Indapamide
- Isradipine
- Levofloxacin
- Lithium
- Moexipril / HCTZ
- Moxifloxacin
- Nicardipine
- Octreotide
- Ofloxacin
- Ondansetron
- Oxytocin
- Paliperidone
- Perflutren
- Quetiapine
- Ranolazine
- Risperidone
- Roxithromycin
- Sunitinib
- Tacrolimus
- Tamoxifen
- Telithromycin
- Tizanidine
- Vardenafil
- Venlafaxine
- Voriconazole
- Ziprasidone
The List of Drugs that Causing Torsades de pointes in Certain Conditions
Drugs that, in some reports, have been weakly associated with torsades de pointes and/or QT prolongation but that are unlikely to be a risk for torsades de pointes when used in usual recommended dosages and in patients without other risk factors (e.g., concomitant QT prolonging drugs, bradycardia, electrolyte disturbances, congenital long QT syndrome, concomitant drugs that inhibit metabolism)
- Amitriptyline
- Amoxapine
- Ciprofloxacin
- Citalopram
- Clomipramine
- Desipramine
- Doxepin
- Fluconazole
- Fluoxetine
- Galantamine
- Imipramine
- Itraconazole
- Ketoconazole
- Mexiletine
- Nortriptyline
- Paroxetine
- Protriptyline
- Sertraline
- Solifenacin
- Trimethoprim-Sulfamethoxazole
- Trimipramine
Characteristics
- Rotation of the heart's electrical axis by at least 180º
- Prolonged QT-interval LQTS
- Preceded by long and short RR-intervals
- Triggered by an early premature ventricular contraction(R-on-T PVC)
Treatment
Acute Treatment
If the episode of does not terminate on its own and degenerates into ventricular fibrillation, cardioversion is required.
Once the patient is back in normal sinus rhythm, a vigorous search for and correction of conditions that predispose to torsades de pointes which include hypokalemia, hypomagnesemia, and bradycardia should be made. Magnesium sulfate (1-2 g IV over 30-60 seconds) reduces the influx of calcium thereby lowering the amplitude of early after depolarizations and should also be infused even if the magnesium is normal. [4][5] Administration of lidocaine is generally not effective, but mexiletene may be helpful in suppressing the recurrence of torsade de pointes.
Additional Information
External Links
Torsade de Pointes related drug list
Examples
EKG's shown below are courtesy of C. Michael Gibson MS MD, and copylefted
 12 lead EKG at admission |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
Examples from different resources
 Arrhythmias in a patient with short coupled torsade de pointes[1] |
 Arrhythmias in a patient with short coupled torsades de pointes degenerating in ventricular fibrillation[1] |
 Arrhythmias in a patient with short coupled torsade de pointes: frequent short coupled extrasystoles[1] |
 Arrhythmias in a patient with short coupled torsade de pointes: frequent short coupled extrasystoles [1] |
 A 12 lead ECG recording example of TdP[6] |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Leenhardt A, Glaser E, Burguera M, Nuernberg M, Maison-Blanche P, and Coumel P. Short-coupled variant of torsade de pointes. A new electrocardiographic entity in the spectrum of idiopathic ventricular tachyarrhythmias. Circulation 1994 Jan; 89(1) 206-15. PMID 8281648
- ↑ Dessertenne F (1966). "[Ventricular tachycardia with 2 variable opposing foci]" (in French). Archives des maladies du coeur et des vaisseaux 59 (2): 263-72. PMID 4956181.
- ↑ Moise NS. As Americans, we should get this right. Circulation 1999 Sep 28; 100(13) 1462. PMID 10500317
- ↑ Hoshino K, Ogawa K, Hishitani T, Isobe T, Eto Y (October 2004). "Optimal administration dosage of magnesium sulfate for torsades de pointes in children with long QT syndrome". J Am Coll Nutr 23 (5): 497S–500S. PMID 15466950.
- ↑ Hoshino K, Ogawa K, Hishitani T, Isobe T, Etoh Y (April 2006). "Successful uses of magnesium sulfate for torsades de pointes in children with long QT syndrome". Pediatr Int 48 (2): 112–7. doi:10.1111/j.1442-200X.2006.02177.x. PMID 16635167.
- ↑ Khan IA. Twelve-lead electrocardiogram of torsade de pointes Tex Heart Inst J. 2001; 28 (1): 69. PMID 11330748
Acknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
