美托洛尔注射液对房室结双径路功能的影响

Electrophysiologic Effects of Intravenous Metoprolol Injection on Dual Atrioventricular Nodal Pathways

目的 评价美托洛尔注射液对房室结双径路功能的影响。 方法 11例房室结折返性心动过速的病人在行射频消融术治疗前接受电生理试验 ,比较静推美托洛尔注射液 (0 .1m g/kg)前后房室结双径路前传有效不应期和传导速度的变化。 结果 静推美托洛尔注射液后 ,快径有效不应期由 338.2± 5 6 .4m s延长至 376 .4±5 3.3ms(P<0 .0 1) ,快径路传导速度由 191.8± 48.1ms延长至 2 18.2± 42 .9ms(P<0 .0 5 ) ;慢径路的有效不应期和传导速度在静推美托洛尔注射液后无显著改变。 结论 (1)美托洛尔注射液主要影响快径路的有效不应期和传导速度 ,对慢径路无明显影响。 (2 )推测房室结的快慢径路是由具有不同电生理特性的细胞参与组成。

Objective\ To evaluate the electrophysiologic effects of intravenous metoprolol injection on patients with atrioventricular nodal(AVN) reentrance tachycardia(AVNRT).\ Methods\ Eleven patients with AVNRT underwent the electrophysiologic study before and after intravenous metoprolol(0 1 mg/kg) before radio frequency catheter ablation.\ The effective refractory period(ERP) and conduction time of antegrade fast AVN pathway and antegrade slow AVN pathway were comparaed.\ Results\ Antegrade fast AVN pathway ERP and conduction time were prolonged by metoprolol(338 2±56 4 ms vs 376 4±53 3 ms,P<0 01;191 8±48 1 ms vs 218 2±42 9 ms,P<0 05 respectively),but the values were unchanged in slow AVN pathway.\ Conclusion\ Intravenous metoprolol have more effect upon ERP and conduction time of antegrade fast AVN pathway than that of slow AVN pathway.\ It indicates that fast pathway and slow pathway are composed of cells with different electrophysiologic properties.\;