Torsade de pointes induced by ioxaglate intracoronary injection in patients with pre-existent drug-induced QT prolongation: case reports and review of literature.

We report two cases of torsade de pointes directly related to intracoronary contrast media injection in patients without previous history of neither arrhythmia nor syncope but chronically treated with a drug prolonging ventricular repolarization. We discussed the effects of the contrast medium used on repolarization and concluded that three suggestions may be highlighted from the case reports presented and from the literature: (i) a QT prolongation should be systematically searched before coronary angiography; (ii) it seems important to correct QT prolongation when it results from a reversible cause (such as drug-induced) before nonurgent coronary angiography; and (iii) if there is no reversible cause explaining QT prolongation, contrast media should be used cautiously in such patient and nonionic iso-osmolar contrast media should be preferred.
(© 2010 The Authors Fundamental and Clinical Pharmacology © 2010 Société Française de Pharmacologie et de Thérapeutique.)