Rare side effects of fluoroquinolones: cardiac toxicity
Torsade de pointes: paroxysm of ventricular tachycardia in which the electrocardiogram shows a steady undulation in the QRS axis in runs of 5 to 20 beats with progressive changes in direction. It is a most severe type of arythmia which may cause death. It is most often associated with and preceeded by a prolongation of the QT interval.
change in QTc prolongation (msec)