Torsades de pointes
685936
221550178
2008-06-25T00:32:28Z
64.118.218.27
/* Causes */
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DiseasesDB = 29252 |
ICD10 = |
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eMedicineSubj = med |
eMedicineTopic = 2286 |
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'''Torsades de pointes''' or '''torsades''' is a [[French language|French]] term that literally means "twisting of the points". It was first described by [[Dessertenne]] in 1966<ref>{{cite journal |author=Dessertenne F |title=[Ventricular tachycardia with 2 variable opposing foci] |language=French |journal=Archives des maladies du coeur et des vaisseaux |volume=59 |issue=2 |pages=263–72 |year=1966 |pmid=4956181 |doi=}}</ref> and refers to a specific variety of [[ventricular tachycardia]] that exhibits distinct characteristics on the [[electrocardiogram]] (ECG).
==Presentation==
The ECG reading in torsades demonstrates 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 can produce [[fainting]]. Although torsade is a rare ventricular [[Cardiac arrhythmia|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. [[Image:Tosadesdepointes.jpg|right|thumb|Characteristic tracing showing the "twisting" (blue line) of Torsade de pointes]]
==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 [[diarrhea]], [[hypomagnesemia]] and [[hypokalemia]]. It is commonly seen in malnourished individuals and chronic [[alcoholism|alcoholics]]. Drug interactions such as [[erythromycin]] or [[moxifloxacin]], taken concomitantly with inhibitors like nitroimidazole, 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:
[[Image:Torsades_converted_by_AICD_ECG_strip_Lead_II.JPG|thumb|right|300px|Lead II [[electrocardiogram]] showing [[Torsades]] being shocked by a [[Implantable cardioverter-defibrillator]] back to the patients baseline [[cardiac rhythm]].]]
* [[Familial long QT syndrome]]
* Class IA [[antiarrhythmic drug|antiarrhythmics]]
* Class III antiarrhythmics
* [[Hypomagnesemia]]
* [[Hypokalemia]]
* [[Hypocalcemia]]
* [[Hypoxia (medical)|Hypoxia]]
* [[Acidosis]]
* [[Heart failure]]
* [[Left ventricular hypertrophy]]
* [[bradycardia|Slow heart rate]]
* [[Female]] gender
* [[Hypothermia]]
* [[Subarachnoid hemorrhage]]
==Treatment==
Treatment is directed at withdrawal of the offending agent, infusion of [[magnesium sulfate]], [[antiarrhythmic drug]]s, and electrical therapy as needed. Because of the polymorphic nature of torsades de pointes, synchronized [[cardioversion]] may not be possible, and the patient may require an unsynchronized shock (or [[defibrillation]]).
==History and 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.
==References==
<references/>
[[Category:Cardiac electrophysiology]]
{{circulatory-stub}}
{{Heart diseases}}
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