Ezri M D, Marchlinski F E, Buxton A E, Waxman H L, Josephson M E
Int J Cardiol. 1983 Jun;3(3):329-37. doi: 10.1016/0167-5273(83)90176-6.
We evaluated the electrophysiologic effects and dose response of the long-acting beta-blocking drug timolol given intravenously to 12 patients during intracardiac electrophysiologic study. Electrophysiologic parameters were measured during control and immediately, 30 minutes, and 48 hours following infusion. Significant changes in electrophysiologic parameters were only observed in the five patients (Group B) who received 0.05 mg/kg and not in the seven patients who received 0.02 mg/kg (Group A). In Group B patients immediately after timolol infusion sinus cycle length increased from 840 +/- 254 msec to 1048 +/- 63 msec (P less than 0.01), A-H interval during normal sinus rhythm increased from 94 +/- 42 msec to 101 +/- 45 msec (P less than 0.05), paced cycle length to A-V nodal Wenckebach increased from 370 +/- 45 msec to 430 +/- 76 msec (P less than 0.05), and A-V nodal effective refractory period increased from 284 +/- 63 msec to 360 +/- 83 msec (P less than 0.01). Significant increases in these electrophysiologic parameters were also noted at 30 minutes following timolol infusion. Other conduction times, atrial and ventricular refractory periods, and corrected sinus node recovery. time were unaltered by timolol. All electrophysiologic parameters returned to control in 48 hours. No adverse effects were observed. We conclude that intravenous timolol in doses of 0.05 mg/kg significantly increases sinus cycle length and prolongs A-V nodal conduction and refractoriness, demonstrates peak effects immediately after intravenous administration, and is well tolerated.
我们评估了长效β受体阻滞剂噻吗洛尔在心脏电生理研究期间静脉注射给12例患者后的电生理效应和剂量反应。在对照期间以及输注后即刻、30分钟和48小时测量电生理参数。仅在接受0.05mg/kg的5例患者（B组）中观察到电生理参数有显著变化，而接受0.02mg/kg的7例患者（A组）未观察到。在B组患者中，噻吗洛尔输注后即刻，窦性周期长度从840±254毫秒增加到1048±63毫秒（P<0.01），正常窦性心律时的A-H间期从94±42毫秒增加到101±45毫秒（P<0.05），起搏周期长度至房室结文氏周期从370±45毫秒增加到430±76毫秒（P<0.05），房室结有效不应期从284±63毫秒增加到360±83毫秒（P<0.01）。在噻吗洛尔输注后30分钟也观察到这些电生理参数有显著增加。其他传导时间、心房和心室不应期以及校正的窦房结恢复时间未受噻吗洛尔影响。所有电生理参数在48小时内恢复到对照水平。未观察到不良反应。我们得出结论，0.05mg/kg剂量的静脉注射噻吗洛尔可显著增加窦性周期长度并延长房室结传导和不应期，静脉给药后即刻显示出峰值效应，且耐受性良好。
