Effects of Ionic Versus Non-ionic Contrast Agents on Dispersion of Ventricular Repolarization

Ionic versus non-ionic centrast agents are used for cardiovascular diagnostic and interventional procedures, and in general, are well tolerated. However a smail percentage of patients develop transient hypotension, bradyarrhythmias, ventricular tachyarrhythmias, or allergic reactions after injection of centrast agents. Ventricular tachyarrhythmias can be dangerous. QT dispersion in surface ECG reflects inhomogeneity of ventricular repolarization and therefore, as a marker for arrhythmia risk. This study was designed to evaluate the proarrhythmic effects of ionic (Ioxaglate) versus non-ionic centrast (Iopamidol) agents in patient with coronary artery disease (CAD). 33 male patients (age: 55.2±9.8 years) with CAD w ere performed coronary angiography. In all patients left ventriculogram preceded the selective injections in the right and left coronary arteries. Ionic centrast agent (Ioxaglate) was given to 16 patients, non-ionic centrast agent (Iopamidol) was given to 17 patients. Before and after left ventriculogram, all patients ECG's were recorded with simultaneous 6-channel-ECG from standard chest leads. High speed (lOOmm/s) and high gain (20mm/m V) ECG recordings w ere tak en and analysed later. All parameters were corrected for heart rate using Bazett formula. Statistical analysis was performed using paired Student-t test; all results are expressed as mean±SD. QTc dispersion (p=0.003), JTc dispersion (p=0.008), TTc dispersion (Tpeak-Tend) (p=0.014), QT dispersion/RR ratio (p=0.0002), JT dispersion/RR ratio (p=0.0015), JTa dispersion/RR ratio(p=0.033), and TT dispersion/RR ratio (p=0.005) were increased in ionic centrast agent (Ioxaglate) group. In non-ionic centrast agent (Iopamidol)"group; TT dispersion/RR ratio (p=0.043) was increased only. Complex premature beats and nonsustained ventricular tachycardia occured in 3 patients and 1 patient used Ioxaglate, in 2 patients and 1 patient used Iopamidol, respectively. Sustained VT or VF did not occur. These data suggest that the non-ionic centrast agent (Iopamidol) results in significantly fewer effects on electrophysiologic parameters, less increase on ventricular excitability than the ionic centrast agent (loxaglate).