Surawicz B, Fisch C
Krannert Institute of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis 46202-4800.
J Am Coll Cardiol. 1992 Aug;20(2):483-99. doi: 10.1016/0735-1097(92)90122-4.
The purpose of this review is to assemble the widely dispersed information about cardiac alternans and to categorize the types and mechanisms of alternans, their clinical manifestations and possible therapeutic implications.
The phenomena of mechanical and electrical alternans have been of continuing interest to both physiologists and clinicians. Recent studies have enhanced this interest because of the reported association of alternans with experimental myocardial ischemia and cardiac arrhythmias.
The review formulates concepts based on extensive review of published studies and personal observations.
Cardiac alternans has been subdivided into the following four categories: 1) mechanical, 2) electrical, 3) in association with myocardial ischemia, and 4) in association with cardiac motion. Mechanical alternans can be explained by hemodynamic or inotropic alterations, or both. Mechanical alternans in the ventricular muscle is accompanied by alternans of action potential shape. In the Purkinje fibers, action potential duration alternates without change in shape and is determined by the duration of the preceding diastolic interval. However, in ventricular muscle fiber, alternans can occur in the presence of constant diastolic intervals. T wave alternans reflects changes in action potential duration and is frequently associated with a long QT interval. Electrocardiographic manifestations of conduction alternans occur at many different sites within the conducting system and myocardium. During myocardial ischemia, additional mechanisms of repolarization alternans have been proposed. Alternans occurring in the presence of a large pericardial effusion is attributed to swinging motion of the heart maintaining two-beat periodicity.
Since its origin as "pulsus alternans" described by Traube in 1872, the definition of alternans has evolved into a term encompassing multiple physiologic and pathologic phenomena that, although united by the term cardiac alternans, diverge widely with respect to etiology, mechanism and clinical significance.
本综述的目的是汇集有关心脏交替脉的广泛分散的信息，并对交替脉的类型和机制、临床表现及可能的治疗意义进行分类。
机械性和电交替脉现象一直是生理学家和临床医生持续关注的问题。由于报道交替脉与实验性心肌缺血和心律失常有关，最近的研究进一步激发了这种兴趣。
本综述基于对已发表研究的广泛回顾和个人观察来阐述概念。
心脏交替脉可分为以下四类：1）机械性；2）电性；3）与心肌缺血相关；4）与心脏运动相关。机械性交替脉可由血流动力学或变力性改变或两者共同解释。心室肌的机械性交替脉伴有动作电位形态的交替。在浦肯野纤维中，动作电位持续时间交替而形态无变化，且由前一个舒张期间隔的持续时间决定。然而，在心室肌纤维中，在舒张期间隔恒定的情况下也可发生交替脉。T波交替脉反映动作电位持续时间的变化，且常与长QT间期相关。传导交替脉的心电图表现出现在传导系统和心肌内的许多不同部位。在心肌缺血期间，已提出复极交替脉的其他机制。在心包大量积液时出现的交替脉归因于心脏的摆动运动维持双搏周期性。
自1872年Traube描述“脉搏交替”以来，交替脉的定义已演变为一个涵盖多种生理和病理现象的术语，这些现象虽然都被称为心脏交替脉，但在病因、机制和临床意义方面差异很大。
