Torsades usually occurs in a pause dependent fashion. 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. It is a polymorphic ventricular tachycardia that exhibits distinct characteristics on the electrocardiogram. A rare complication of an extraadrenal pheochromocytoma article pdf available in hypertension research 3012.
Waldo, md, facc birmingham, alabama the clinical setting, precipitating factors, electrocardiographic. A prolonged qt interval on the surface ecg is a surrogate measure of prolonged ventricular action potential duration apd. It was described by french physician francois dessertenne in 1966. It is a polymorphic ventricular tachycardia that exhibits distinct characteristics on the electrocardiogram ecg. This is a form of vt where there is usually no difficulty in recognising its ventricular origin. This abnormal qt morphology, which has been well described for the. Behr3 1medical toxicology centre, wolfson building, institute of cellular medicine, newcastle university. This abnormal qt morphology, which has been well described for the congenital lqts, is also observable in the. I have strange feelings due to knowing this side effect. Prolongation of the qt interval can increase a persons risk of developing this abnormal heart rhythm.
Poly just implies that there are multiple, that there are multiple qrs intervals. It is characterized by rapid, irregular qrs complexes, which appear to be twisting around the electrocardiogram ecg baseline. Pharmacological treatment of acquired qt prolongation and. The qt interval in the long qt syndrome lqts is not only prolonged but also odd looking.
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 patient with torsade who is in extremis should be treated with electrical cardioversion or defibrillation. In torsades you have a long qt thats followed by a polymorphic vtach. Torsades can be caused by either congenital longqt syndrome or acquired longqt syndrome due to electrolyte abnormalities andor medications. The patients additional psychiatric medications, quetiapine and fluoxetine, likely potentiated this effect.
Known risk of tdp kr, possible risk of tdp pr or have a conditional risk of tdp cr. Mechanisms, risk factors, and management of acquired long qt. Torsades definition of torsades by medical dictionary. Pacing at rates up to 140 bpm may prevent the ventricular pauses that allow tdp to originate. It will appear as if there is twisting of the qrs complexes around the isoelectric line. What clinicians should know about the qt interval anestesiar. The ventricles are the two lower chambers of the heart that. Patients with organic heart disease, with low serum electrolyte levels, with a previous episode of tdp and with bradycardia or baseline qt. The vast majority of torsades results from acquired longqt syndrome. Frpharms, cchem, frsc, fpsni, in a manual of adverse drug interactions fifth edition, 1997. Many medications and medical conditions cause acquired long qt syndrome.
According to the naranjo probability scale, the episode in this case was probably related to administration of intravenous moxifloxacin. The longshort initiating sequence and other clinical features. It is usually drug related and may be either selflimiting or progressing to ventricular fibrillation. In patients with underlying risk factors for a prolonged qt interval. Torsades is lifethreatening, and can be made worse by many drugs, including some of the drugs used to treat vt. Ecg showing the qrs complexes twisting around the isoelectric line. Pdf proton pump inhibitors and serum magnesium levels in. E uma emergencia medica e pode causar morte subita cardiaca. However, long qt syndrome can lead to tdp is left alone and unrecognized. The first thought that comes to my mind when i hear this term is the wellrenowned french pastry.
However, there is more to this term than a delicious, crunchy sweet from paris. 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. Genetic bases for atrioventricular blockinduced torsades. It usually manifests in patients with abnormalities of repolarization. It is a condition that requires prompt diagnosis and treatment.
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