Electrophysiological effects of ibutilide on normal cardiac conduction system and accessory pathways / 第二军医大学学报

ABSTRACT

Objective: To observe the electrophysiological effects of ibutilide on the normal cardiac conduction system and accessory pathways (AP) of patients with accessory pathways mediated reentrant tachycardia (AVRT) and to assess the safety of ibutilide in electrophysiology study (EPS) and radiofrequency catheter ablation (RFCA). Methods: Twenty-one patients with AVRT undergoing EPS received intravenous ibutilide (1 mg). Electrophysiological parameters, including P-A interval, A-H interval, H-V interval, QRS complex width, QT interval, paced QT interval, right atrial effective refractory period (RA ERP), right ventricular ERP (RV ERP)q atrioventricular node ERP (AVN ERP), AVN block cycle length (AVN BCD, antegrade AP ERP and retrograde AP ERP 9 were observed before and instantly, 15 min, and 30 min after injection of ibutilide. Results: There was no statistical difference in the P-A interval, A-H interval, H-V interval and QRS complex width before and after ibutilide injection(P>0.05). After injection of ibutilide, the QTc, QT intervals, the RA ERP, RV ERP, and AVN BCL were all significantly prolonged (P<0.05). The antegrade and retrograde ERP of AP were also increased (P<0.05), with no loss of antegrade and retrograde function of AP. All patients underwent successful ablation and Torsade de pointes (Tdp) and no other adverse effects were noticed. Conclusion: Ibutilide has no effect on the conductivity of normal cardiac conduction system. Routine dosage of ibutilide can prolong ERP of AP but does not block the conductivity, with no influence on electrophysiology study and radiofrequency catheter ablation. Ibutilide has no adverse effect on patients with AVRT.