Henery Daniel, Tummala Ramyashree
Legacy Health
Mount Sinai Beth Israel
Pulsus alternans (PA), not to be confused with pulsus paradoxus or electrical alternans, is an arterial pulse with alternating strong and weak beats. It is a hemodynamic phenomenon marked by a beat-to-beat alternation in the amplitude of the pulse resulting in a clinically identifiable pulse half of the electrical rate. In 1872, Ludwig Traube first described this phenomenon. Systolic pressures will vary from beat to beat as identified on physical exam and echocardiogram. Pulsus alternans is found in the setting of severe ventricular dysfunction and other forms of cardiac pathology. Variations of pulsus alternans include left ventricular alternans, right ventricular alternans, and biventricular alternans. The treatment and clinical outcomes for pulsus alternans vary depending upon the underlying causative etiology, though its presence generally suggests a poor prognostic outlook. Pulsus alternans usually occurs in association with severe heart disease and can eventually lead to pulseless electrical activity. See Diagram of Electrical Alterans, Pulsus Alterans, and Pulsus Paradoxus.
交替脉（PA），不要与奇脉或电交替混淆，是一种强弱搏动交替的动脉脉搏。它是一种血流动力学现象，其特征是脉搏幅度逐搏交替，导致临床上可识别的脉搏频率为电频率的一半。1872年，路德维希·特劳贝首次描述了这种现象。体格检查和超声心动图显示收缩压会逐搏变化。交替脉见于严重心室功能障碍和其他形式的心脏病理情况。交替脉的变异包括左心室交替脉、右心室交替脉和双心室交替脉。交替脉的治疗和临床结果因潜在病因不同而有所差异，尽管其出现通常提示预后不良。交替脉通常与严重心脏病相关，最终可导致心脏停搏。见电交替、交替脉和奇脉示意图。
