Iohexol contrast medium induces QT prolongation in amiodarone patients.
OBJECTIVE
Amiodarone is widely used in ventricular tachyarrhythmias and atrial fibrillation, known to prolong QT-intervals. Concurrent administration of drugs prolonging QT- time can induce life-threatening ventricular tachyarrhythmia.


METHODS
QT-interval changes following use of Iohexol contrast-medium for coronarangiography were observed comparing 21 patients taking long-term amiodarone therapy with 21 controls not taking amiodarone or QT-prolonging drugs retrospectively.


RESULTS
Concurrent use of Iohexol and amiodarone was associated with significant prolongation of QTc-interval (433, 95%CI: 419-448 ms vs. 480, 95%CI: 422-483 ms, P < 0.001) the day after coronarangiograpgy. 6/21 patients showed severe prolonged QTc-interval of >500 ms.


CONCLUSIONS
Caution is advised until more is known about pro-arrhythmic effects of Iohexol.
Goernig
Matthias
M
Friedrich-Schiller-University, Clinic of Internal Medicine III, Erlanger Allee 101, D-07740 Jena, Germany. Matthias.Goernig@med.uni-jena.de
Kirmeier
Thomas
T
Krack
Andreas
A
Hartog
Christiane S
CS
Figulla
Hans R
HR
Leder
Uwe
U
D000638:Amiodarone / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D003287:Contrast Media / Q000009:adverse effects*; D006801:Humans; D007472:Iohexol / Q000009:adverse effects*; D008133:Long QT Syndrome / Q000139:chemically induced*; D012189:Retrospective Studies; D017180:Tachycardia, Ventricular / Q000188:drug therapy*
D000889:Anti-Arrhythmia Agents; D003287:Contrast Media; D007472:Iohexol; D000638:Amiodarone