Newman D, Dorian P, Feder-Elituv R
St. Michael's Hospital, Division of Cardiology, Toronto, ON, Canada.
Can J Physiol Pharmacol. 1993 Oct-Nov;71(10-11):755-60. doi: 10.1139/y93-113.
The effects of an isoproterenol infusion on the duration of the human right ventricular endocardial monophasic action potential at 90% repolarization were recorded in the absence and in the presence of an antiarrhythmic drug regimen containing class III effects in two similar groups of patients. The drugs used were amiodarone (N = 3, 300 +/- 50 mg), sotalol plus quinidine (N = 11, 156 +/- 13 mg sotalol, 1688 +/- 594 mg quinidine), and sotalol alone (N = 3, 300 +/- 20 mg). All patients had underlying coronary disease but no evidence of inducible ischemia. In the absence of antiarrhythmic drug, isoproterenol did not significantly change the relationship of action potential duration at 90% repolarization to cycle length; there was a linear decrease in action potential duration by 19.8% between a paced cycle length of 600 and 300 ms. Isoproterenol did not significantly shorten the action potential duration at any cycle length. However, isoproterenol decreased the ventricular effective refractory period at 400 ms drive from 240 +/- 5.0 to 225 +/- 6.0 ms (p < 0.05) accompanied by no change in the ratio of refractory period to steady-state action potential duration. In the presence of class III drug effects, the action potential duration was increased by an average of 9.2% at all paced cycle lengths longer than 300 ms (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
在两组相似的患者中，分别在不存在和存在具有Ⅲ类效应的抗心律失常药物方案的情况下，记录异丙肾上腺素输注对人类右心室心内膜单相动作电位在复极化90%时的时程的影响。所用药物为胺碘酮（N = 3，300±50 mg）、索他洛尔加奎尼丁（N = 11，156±13 mg索他洛尔，1688±594 mg奎尼丁）和单独使用索他洛尔（N = 3，300±20 mg）。所有患者均有潜在的冠状动脉疾病，但无诱发性缺血的证据。在无抗心律失常药物的情况下，异丙肾上腺素并未显著改变复极化90%时动作电位时程与心动周期长度的关系；在起搏周期长度从600 ms降至300 ms时，动作电位时程呈线性下降19.8%。异丙肾上腺素在任何心动周期长度下均未显著缩短动作电位时程。然而，异丙肾上腺素使以400 ms驱动时的心室有效不应期从240±5.0 ms降至225±6.0 ms（p<0.05），而不应期与稳态动作电位时程的比值无变化。在存在Ⅲ类药物效应的情况下，在所有长于300 ms的起搏周期长度下，动作电位时程平均增加9.2%（p<0.05）。（摘要截短于250字）
