Jm. Idee et al., ROLE OF SODIUM IN CONTRAST MEDIUM-INDUCED POLYMORPHIC VENTRICULAR-TACHYCARDIA - RESULTS IN A RABBIT MODEL OF LENGTHENED QT INTERVAL, Academic radiology, 5(6), 1998, pp. 435-443
Rationale and Objectives. The authors (a) compared the proarrhythmic e
ffects of ioxaglate (152 mmol/L sodium) and iohexol (no sodium) in a r
abbit model and (b) assessed the effect of adding 150 mmol/L sodium to
isotonic iohexol. Materials and Methods. Either ioxaglate (320 mg of
iodine per milliliter) or iohexol (350 mg of iodine per milliliter) wa
s selectively injected into the right coronary artery (1.5 mL over 30
seconds) of 10 rabbits, some of which also received the alpha(1)-adren
ergic receptor agonist methoxamine. To validate the model, the class I
II antiarrhythmic agent clofilium was injected intravenously during me
thoxamine infusion. Frontal electrocardiography was performed continuo
usly to detect polymorphic ventricular tachycardia (PVT). In a second
study, the authors assessed the frequency of arrhythmias after injecti
on of isotonic iohexol solution (145 mg of iodine per milliliter), eit
her alone or with 150 mmol/L sodium. Results. Methoxamine significantl
y lengthened the QT, QTc, and RR intervals (P < .05). The use of clofi
lium alone induced no PVT, whereas five of eight methoxamine-infused r
abbits developed PVT after clofilium injection (P = .03). Both contras
t media prolonged the repolarization period. Iohexol alone induced a h
igher frequency of PVT than did ioxaglate alone (P = .0006). Methoxami
ne infusion did not potentiate the frequency of PVT in the ioxaglate-i
njected rabbits. The addition of sodium to isotonic iohexol prevented
the occurrence of PVT ( P = .0006). Conclusion. Although ioxaglate pro
longed the repolarization period, it did not cause a higher frequency
of arrhythmia when injected in association with methoxamine. Iohexol,
which contains no sodium, induced a high frequency of arrhythmia. The
addition of a physiologic concentration of sodium to isotonic iohexol
can prevent ventricular arrhythmias.