Gmeiner R, Ng C K
J Cardiovasc Pharmacol. 1982 Jan-Feb;4(1):5-13. doi: 10.1097/00005344-198201000-00003.
The effect of metoprolol on paroxysmal reentrant supraventricular tachycardia was studied in 30 patients. In 16 cases (12 accessory pathway, 4 pure AV nodal reentry) programmed stimulation was performed before and after 0.1 mg/kg intravenous metoprolol. When administered during sustained tachycardia, metoprolol terminated the arrhythmia in 4 out of 12 cases. Metoprolol prolonged the AV nodal functional and effective refractory period and the A-H interval but had no effect on refractory periods and conduction intervals of accessory pathways. Following metoprolol no tachycardia could be initiated in five patients. Premature atrial pacing revealed widened tachycardia zones in 10 cases; premature ventricular pacing showed varying responses to the drug. Twenty two patients (13 accessory pathway, 9 pure AV nodal reentry) received two times 50 to two times 100 mg metoprolol orally per day and were followed for 4 weeks. Five patients did not complete the entire term, four because of frequent tachycardia and one because of side effects. Ten patients were free of arrhythmia, most over several months, and seven continued to have attacks. Plasma levels were higher on oral metoprolol. Intravenous testing had correctly predicted the response to oral metoprolol in seven out of eight patients. Higher plasma concentrations, suppression of premature beats, or the different patient population may explain the more favorable prophylactic action of oral metoprolol.
对30例阵发性折返性室上性心动过速患者研究了美托洛尔的疗效。16例患者（12例为旁路，4例为单纯房室结折返）在静脉注射0.1mg/kg美托洛尔前后进行了程序刺激。在持续性心动过速发作时给药，美托洛尔使12例中的4例心律失常终止。美托洛尔延长了房室结功能和有效不应期以及A-H间期，但对旁路的不应期和传导间期无影响。美托洛尔治疗后，5例患者未能诱发心动过速。房性早搏起搏显示10例患者的心动过速区增宽；室性早搏起搏对该药表现出不同反应。22例患者（13例为旁路，9例为单纯房室结折返）每天口服两次50至两次100mg美托洛尔，并随访4周。5例患者未完成整个疗程，4例因频繁心动过速，1例因副作用。10例患者无心律失常，多数持续数月，7例仍有发作。口服美托洛尔时血浆水平较高。静脉试验在8例患者中的7例中正确预测了对口服美托洛尔的反应。较高的血浆浓度、早搏的抑制或不同的患者群体可能解释了口服美托洛尔更有利的预防作用。
