Halpern M S, Chiale P A, Nau G J, Przybylski J, Lázzari J O, Elizari M V, Rosenbaum M B
Circulation. 1980 Dec;62(6):1357-64. doi: 10.1161/01.cir.62.6.1357.
An isoproterenol infusion (1.0-4.0 microgram/min) was administered to 15 patients with intermittent bundle branch block (BBB) and two patients with apparently fixed BBB. Three main effects were documented: (1) In all patients with phase 3, or tachycardia-dependent, BBB, isoproterenol caused a pronounced shortening of refractoriness in the affected fascicle. (2) In patients showing phase 4, or bradycardia-dependent, BBB, isoproterenol prolonged the phase 4 block range, probably because of enhanced diastolic depolarization. In one patient (four studies) in whom phase 4 block was not present, isoproterenol caused the appearance of a phase 4 block range. (3) In the two patients with fixed BBB, isoproterenol restored conduction, probably as a result of a hyperpolarizing effect. This study shows that isoproterenol tends to restore or improve conduction related to tachycardia-dependent block, but may impair conduction related to bradycardia-dependent block.
对15例间歇性束支传导阻滞（BBB）患者和2例明显固定性BBB患者输注异丙肾上腺素（1.0 - 4.0微克/分钟）。记录到三种主要效应：（1）在所有有3相或心动过速依赖性BBB的患者中，异丙肾上腺素使受影响束支的不应期明显缩短。（2）在表现为4相或心动过缓依赖性BBB的患者中，异丙肾上腺素延长了4相阻滞范围，可能是由于舒张期去极化增强。在1例（四项研究）不存在4相阻滞的患者中，异丙肾上腺素导致出现了4相阻滞范围。（3）在2例固定性BBB患者中，异丙肾上腺素恢复了传导，可能是超极化作用的结果。本研究表明，异丙肾上腺素倾向于恢复或改善与心动过速依赖性阻滞相关的传导，但可能损害与心动过缓依赖性阻滞相关的传导。
