Letter to the Editor Torsades de pointes with a severely prolonged QT interval induced by an initial low dose sotalol intake Kenan Yalta ⁎ , Okan Turgut, Ahmet Yilmaz, M. Birhan Yilmaz, Omer Kendirlioglu, Filiz Karadas Department of Cardiology, Faculty of Medicine, Cumhuriyet University, Sivas, 58030, Turkey Received 27 July 2006; received in revised form 8 August 2006; accepted 11 August 2006 Available online 27 November 2006 Abstract Many drugs, including sotalol, have been implicated in prolonging QT interval and triggering torsades de pointes, a potentially fatal ventricular arrhythmia, especially during chronic therapy or in case of acute high dose toxicity. We report here a case with a severely prolonged QT interval and torsades de pointes after an initial intake of low dose sotalol (80 mg), indicating a probable inherent individual oversensitivity to sotalol. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Torsades de pointes; Sotalol; QT interval 1. Introduction New-onset prolonged QT interval has generally been regarded as an electrocardiographical finding associated with the use of certain agents such as sotalol, and severe QT interval prolongation may portend torsades de pointes (TdP). Howev- er, at therapeutic doses, the development of fatal ventricular arrhythmias is rarely seen. The case presented here represents an unexpectedly and rapidly evolved severe QT interval pro- longation and TdP in response to initial low dose sotalol (80 mg) intake, raising the probability of an inherent individual oversensitivity. 2. Case report A 30-year-old female patient was admitted to our hospital with the complaints of palpitation, presyncope and atypical chest pain. A brief medical history explicitly revealed an intake of 80 mg of sotalol (1 tb) by mistake instead of an analgesic drug to relieve her atypical chest pain approximately 6 h before admission . Her husband had been taking sotalol for 3 years for the prophylaxis of atrial fibrillation. Nearly 2 h after the initial dose, visual blurring, fatigue, loss of balance, preceded by slight dizziness were the major embarrassing symptoms that compelled the patient to seek medical aid; however, rapid disappearance of symptoms after resting in recumbent position for a while deterred her from further help. As hours elapsed, the symptoms insidiously progressed to a relapsing, remitting pattern in which each bout became more prolonged and decapacitating, and eventually coerced her husband to trans- port her to emergency department. She surely confirmed that she had never encountered such disabling symptoms before neither had the other family members. On physical examina- tion, the blood pressure was 85/55 mm Hg and a mild pan- systolic murmur was best audible at apex. Serum parameters including renal, liver and thyroid function tests, and electro- lytes were all within normal range. There was no history of any other drug intake that might augment proarrhythmic effects of sotalol. Sotalol concentration on admission was found to be 0.4 μg/ml (effective therapeutic serum concentration for sotalol is in the range of 2.5 μg/ml). Initial ECG on admission exhibited intermittent polymorphic ventricular tachycardia, International Journal of Cardiology 116 (2007) e95 – e97 www.elsevier.com/locate/ijcard Abbreviations: DC, direct current; ECG, electrocardiogram; QTc, corrected QT; TdP, torsades de pointes. ⁎ Corresponding author. Tel.: +90 346 219 13 00x2126, +90 5056579856 (cell). E-mail address: kyalta@gmail.com (K. Yalta). 0167-5273/$ - see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2006.08.091