Azithromycin as a cause of QT-interval prolongation and torsade de pointes in the absence of other known precipitating factors

J Interv Card Electrophysiol (2007) 18:243246 DOI 10.1007/s10840-007-9124-y

CASE REPORT

Azithromycin as a cause of QT-interval prolongation and torsade de pointes in the absence of other known precipitating factors

Anna Kezerashvili & Himad Khattak & Aron Barsky &

Reza Nazari & John D. Fisher

Received: 31 July 2006 / Accepted: 3 April 2007 / Published online: 2 June 2007 # Springer Science + Business Media, LLC 2007

Abstract During treatment with azithromycin, a 55 year-old woman developed a newly prolonged QT interval and torsade de pointes in the absence of known risk factors. Female gender and acute renal failure may be considerations in patients treated with azithromycin.

Keywords Azithromycin . QT interval .

Torsade de Pointes . LQTS

1 Introduction

The long QT syndrome (LQTS) is characterized by prolongation of the QT interval, which can be congenital or acquired. The acquired form has a long QT interval caused by various cardiovascular and non-cardiovascular drugs, electrolyte abnormalities, central nervous system lesions and other medical conditions. [1]

Q-T prolongation, whether congenital or acquired, is associated with the development of the malignant arrhythmia torsade de pointes (a polymorphic ventricular tachycardia), that may result in sudden death [2]. We are reporting a case of QT-interval prolongation and torsade de pointes apparently precipitated by azithromycin. Unlike previous reports, this patient was not taking other medications known to cause QT prolongation or have other risk factors for LQTS.

2 Case report

A 55-year-old female who had a pacemaker for intermittent symptomatic bradycardia presented elsewhere with headache, generalized body weakness and chills for 2 days. Cultures were positive for Staphylococcus aureus. She was started on gentamicin and vancomycin and transferred to Montefiore. On admission, she reported no chest pain, shortness of breath, nausea or vomiting. Her past medical history included hypertension and symptomatic bradycardia. Her medications included atorvastatin, quinapril, metoprolol, niacin, aspirin and multivitamins. She did not take any opiates, herbal or antipsychotic medications. Physical examination revealed a flushed face with no evidence of fever on gentamicin and vancomycin. Breath sounds were normal. Cardiac auscultation showed normal heart sounds without murmurs or gallops. The patients baseline 12-lead ECG taken a week before admission showed normal sinus rhythm at 40 beats per minute, normal axis, normal PR interval of 160 ms, QT 520...