Torsades definition of torsades by medical dictionary. What clinicians should know about the qt interval anestesiar. Mechanisms, risk factors, and management of acquired long qt. It is usually drug related and may be either selflimiting or progressing to ventricular fibrillation. In torsades you have a long qt thats followed by a polymorphic vtach. However, there is more to this term than a delicious, crunchy sweet from paris. Genetic bases for atrioventricular blockinduced torsades. Ecg showing the qrs complexes twisting around the isoelectric line.
Pharmacological treatment of acquired qt prolongation and. This abnormal qt morphology, which has been well described for the congenital lqts, is also observable in the. Pacing at rates up to 140 bpm may prevent the ventricular pauses that allow tdp to originate. It is a condition that requires prompt diagnosis and treatment. This arrhythmia may cease spontaneously or degenerate into ventricular fibrillation. According to the naranjo probability scale, the episode in this case was probably related to administration of intravenous moxifloxacin. It was described by french physician francois dessertenne in 1966. This abnormal qt morphology, which has been well described for the. Pdf proton pump inhibitors and serum magnesium levels in. Frpharms, cchem, frsc, fpsni, in a manual of adverse drug interactions fifth edition, 1997. A rare complication of an extraadrenal pheochromocytoma article pdf available in hypertension research 3012. It is a polymorphic ventricular tachycardia that exhibits distinct characteristics on the electrocardiogram. A prolonged qt interval on the surface ecg is a surrogate measure of prolonged ventricular action potential duration apd.
Torsades is lifethreatening, and can be made worse by many drugs, including some of the drugs used to treat vt. Eads were observed at three out of five right ventricular sites during escape rhythm. Prolongation of the qt interval can increase a persons risk of developing this abnormal heart rhythm. Despite its low frequency, druginduced tdp has generated a great deal of angst among physicians and pharmaceutical companies as well as tragedy, albeit rare, among patients. In patients with underlying risk factors for a prolonged qt interval.
It usually manifests in patients with abnormalities of repolarization. Patients with organic heart disease, with low serum electrolyte levels, with a previous episode of tdp and with bradycardia or baseline qt. It is characterized by rapid, irregular qrs complexes, which appear to be twisting around the electrocardiogram ecg baseline. The first thought that comes to my mind when i hear this term is the wellrenowned french pastry.
The patients additional psychiatric medications, quetiapine and fluoxetine, likely potentiated this effect. E uma emergencia medica e pode causar morte subita cardiaca. The qt interval in the long qt syndrome lqts is not only prolonged but also odd looking. The longshort initiating sequence and other clinical features. Many medications and medical conditions cause acquired long qt syndrome. However, long qt syndrome can lead to tdp is left alone and unrecognized. It will appear as if there is twisting of the qrs complexes around the isoelectric line.
The vast majority of torsades results from acquired longqt syndrome. We present a case of tdp caused by a prolonged qt associated with polypharmacy and substance abuse in a patient with human immunodeficiency virus hiv infection. Behr3 1medical toxicology centre, wolfson building, institute of cellular medicine, newcastle university, newcastle upon tyne ne2 4hh,2national poisons information service newcastle unit, newcastle hospitals nhs foundation trust, newcastle upon tyne ne1. This is a form of vt where there is usually no difficulty in recognising its ventricular origin. The patient with torsade who is in extremis should be treated with electrical cardioversion or defibrillation. Since its initial description by jervell and langenielsen in 1957,1 congenital long qt syndrome lqts has been the most investigated cardiac ion channelopathy. The ventricles are the two lower chambers of the heart that.
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