Electrophysiologic Effects of Quinidine: Studies Using Chronically Implanted Electrodes in Awake Dogs with and Without Cardiac Denervation
Electrophysiologic Effects of Quinidine: Studies Using Chronically Implanted Electrodes in Awake Dogs with and Without Cardiac Denervation
复制标题
奎尼丁的电生理效应：在有或没有心脏去神经支配的清醒狗中使用长期植入电极的研究
作者：
A. Wallace;R. Cline;W. Sealy;W. Young;W. G. Troyer
在清醒的狗上进行实验，在SA结、His束和右束分支上植入慢性记录电极。血清浓度为5至10 mg/L的奎尼丁对AV传导影响不大，但减慢浦肯野组织的传导，延长心室激动，降低心房和心室的兴奋性，延长心房不应期，但对心室不应期没有一致的影响。奎尼丁可使去心脏神经的清醒犬心房、心室的兴奋性降低，不应期延长。奎尼丁对兴奋性的影响取决于用于测试兴奋性的刺激的持续时间。奎尼丁对心室内传导和兴奋性的作用在快速刺激时增强。这些数据表明，在通常认为在治疗范围内的血清奎尼丁浓度下，一致地观察到心室内传导减慢，但未一致地观察到心室不应期的变化。虽然奎尼丁的迷走神经阻滞特性可能有助于心率的变化，但它们似乎并不显著影响奎尼丁对心房不应性和AV传导的作用。
Experiments were performed on awake dogs with chronic recording electrodes implanted on the SA node, His bundle, and right bundle branch. Quinidine at serum concentrations of 5 to 10 mg/liter had little effect on AV conduction, but slowed conduction in Purkinje tissue, prolonged ventricular activation, decreased the excitability of atrium and ventricle, and prolonged the atrial refractory period without a consistent effect on the ventricular refractory period. In awake dogs that had previously undergone cardiac denervation, quinidine decreased the excitability and prolonged the refractory period of atrium and ventricle. The effects of quinidine on excitability were dependent on the duration of the stimulus used to test excitability. The actions of quinidine on intraventricular conduction and excitability were enhanced at rapid rates of stimulation. These data indicate that slowing of intraventricular conduction is observed consistently at serum quinidine concentrations that are generally considered to be within the therapeutic range, but changes of the refractory period of the ventricle are not observed consistently. Although the vagolytic properties of quinidine may contribute to changes of heart rate, they do not appear to influence significantly the effects of quinidine on atrial refractoriness and AV conduction.