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Int J Angiol 2006; 15(1): 16-19
DOI: 10.1007/s00547-006-2048-z
© Georg Thieme Verlag KG Stuttgart · New York

The effects of intravenous levofloxacin on the QT interval and QT dispersion

Salman Haq1 , Masi Khaja2 , Jeffery J. Holt3 , John Kassotis4
  • 1Division of Cardiology, New York Methodist Hospital, Brooklyn, NY
  • 2Department of Medicine, New York Methodist Hospital, Brooklyn, NY
  • 3SUNY Downstate—University Hospital of Brooklyn, Brooklyn, NY, USA
  • 4Clinical Cardiac Electrophysiology Service, SUNY Downstate—University Hospital of Brooklyn, Brooklyn, NY, USA
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Publication History

Publication Date:
27 April 2011 (online)

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Abstract

The QT dispersion (QTd) is a non-invasive means of identifying those patients at an increased risk of developing sudden cardiac death (SCD). Although levofloxacin has a minimal effect on the QTc interval, isolated reports of QT prolongation, polymorphic ventricular tachycardia with a normal QT interval and TdP have been reported. The purpose of this study was to examine the effect of intravenous levofloxacin on the QT interval and QTd. Of the 50 patients who were deemed candidates to receive intravenous levofloxacin, 29 met the eligibility criteria and were enrolled in this study. A 12-lead ECG was performed before the initiation of levofloxacin (baseline), and on days 3 and 5. The QTc min, QTc max and the QTd were calculated. Measurements where made by two independent observers blinded to the patients' clinical status. The QTd increased significantly on days 3 and 5 following the initiation of therapy [QTd (baseline) 33.3 ± 20 ms, QTd (day 3) 64.4 ± 31.3 ms (p = 0.023), QTd (day 5) 66.8 ± 20.3 ms, (p = 0.008)]. The increase in the QTd was significantly longer in men than women. Although women had a shorter baseline QTd compared to men, this did not achieve statistical significance. Intravenous levofloxacin was found to significantly increase the QTd, which was more pronounced in men compared to women. Its effect on the QTd may increase the risk of developing a potentially fatal ventricular arrhythmia. Therefore, care must be taken when prescribing this medication to patients with a pre-existing risk of developing SCD.

List of Abbreviations

QTc max : Maximum corrected QT interval on the 12-lead electrocardiogram
QTc min : Minimum corrected QT interval on the 12-lead electrocardiogram
QTd : Difference between the maximum and minimum QT interval
SCD: Sudden cardiac death
VT: Ventricular tachycardia
TdP: Torsade de Pointes

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