A Toxic Combination

Zeineh examines the case of 73-year-old man with a known history of chronic obstructive pulmonary disease. He was promptly intubated by the emergency department physicians, placed on mechanical ventilation, and given intravenous levofloxacin and corticosteroids. He was transferred to the medical intensive care unit for management. An electrocardiogram (ECG) taken at admission showed signs of left ventricular hypertrophy and a QT interval corrected for heart rate of 450 msec. The patient's ECG changes and arrhythmia were multifactorial in etiology. Specifically, the diagnosis was levofloxacin-induced QT prolongation in the context of severe left ventricular dysfunction and chronic amiodarone therapy. The administration of levofloxacin in combination with amiodarone therapy precipitated the patient's ECG changes and arrhythmia.