Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Sep 2002
Case ReportsIndapamide induced syncope in a patient with long QT syndrome.
A 60-year-old woman who had been successfully treated with atenolol and cardiac pacing for hypertension and long QT syndrome developed recurrent episodes of palpitations and syncope. Several days prior to these episodes, indapamide 2.5 mg/day was taken for better control of hypertension. ⋯ Indapamide was immediately stopped, but the QT remained prolonged 2 days later, although the potassium level was normalized. This case suggests that indapamide can cause potassium independent prolongation of the QT interval, resulting in arrhythmia induced syncope.
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Pacing Clin Electrophysiol · Apr 2002
Case ReportsIntoxication with taxus baccata: cardiac arrhythmias following yew leaves ingestion.
The use of yew leaves (Taxus Baccata) as a means of deliberate self-harm is infrequent. The potent effect of the toxin is primarily cardiac and results in rhythm alterations and ultimately ventricular fibrillation. ⋯ This case describes a 43-year-old women who attempted suicide by ingesting the leaves of Taxus Baccata. We discuss the effects and the difficulty of treatment associated with yew leaf poisoning.
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Pacing Clin Electrophysiol · Feb 2002
The imprecision in heart rate correction may lead to artificial observations of drug induced QT interval changes.
Because of the known limitations of the Bazett and other heart rate correction formulas, it has been proposed that studies of drug induced QT interval changes should use several different heart rate correction formulas and that the consistency of findings by a majority of such formulas should be considered as valid. The aim of this article was to show that such an approach is inappropriate. Using the database of the EMIAT trial, data of QT and RR intervals were taken from electrocardiograms of the first postrandomization visit of 1,402 patients. ⋯ Formulas that provided QTc intervals almost independent of the RR intervals estimated approximately 20 ms QTc prolongation on amiodarone and no QTc change on beta-blockers. QT/RR regression analysis confirmed that while amiodarone led to substantial QT prolongation, there was no change of QT interval on beta-blockers beyond the change in heart rate. The study showed that the concept of "majority voting" by different heart rate correction formulas is inappropriate and may lead to erroneous conclusions.