Pulsus alternans

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Varun Kumar, M.B.B.S.

Overview

Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats. It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis.

Pathophysiology

In left ventricular dysfunction, the ejection fraction will decrease significantly, causing reduction in stroke volume, hence causing a increase in end-diastolic volume. There may initially be a tachycardia as a compensatory mechanism to try to keep the cardiac output constant. As a result, during the next cycle of systolic phase, the myocardial muscle will be stretched more than usual and as a result cause an increase in myocardial contraction, related to the Frank–Starling physiology of the heart. This in turn results in a stronger systolic pulse.

Causes

Causes by Organ System

Cardiovascular	No underlying causes
Chemical / poisoning	No underlying causes
Dermatologic	No underlying causes
Drug and Toxin Side Effect	No underlying causes
Ear Nose Throat	No underlying causes
Endocrine	No underlying causes
Environmental	No underlying causes
Gastroenterologic	No underlying causes
Genetic	[No underlying causes
Hematologic	No underlying causes
Iatrogenic	No underlying cause
Infectious Disease	No underlying causes
Musculoskeletal / Ortho	No underlying causes
Neurologic	No underlying cause
Nutritional / Metabolic	No underlying cause
Obstetric/Gynecologic	No underlying cause
Oncologic	No underlying causes
Opthalmologic	No underlying causes
Overdose / Toxicity	[No underlying causes
Psychiatric	No underlying causes
Pulmonary	No underlying causes
Renal / Electrolyte	No underlying causes
Rheum / Immune / Allergy	No underlying causes
Sexual	No underlying causes
Trauma	No underlying causes
Urologic	No underlying causes
Miscellaneous	No underlying causes

Related Chapters

Congestive cardiac failure