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	Atrial Septal Defects, cor triatriatum, left heart failure, fallot tetralogy, persistent fetal circulation, mitral valve stenosis, mitral valve insufficiency, ventricular Septal Defect
Chemical / poisoning	No underlying causes
Dermatologic	No underlying causes
Drug and Toxin Side Effect	No underlying causes
Ear Nose Throat	Pickwickian syndrome.
Endocrine	Thyroid diseases.
Environmental	High Altitude(chronically).
Gastroenterologic	Portal Hypertension.
Genetic	Alveolar capillary dysplasia with misalignment of pulmonary veins, cholesterol ester storage disease, cystic fibrosis, Gaucher disease, Indian familial childhood cirrhosis
Hematologic	Myeloproliferative disorders, paroxysmal nocturnal haemoglobinuria, polycythemia Vera, splenectomy(due to thrombophilia), sickle cell disease.
Iatrogenic	No underlying cause
Infectious Disease	HHV-8, schistosoma japonicum and schistosoma mansoni
Musculoskeletal / Ortho	Idiopathic spinal scoliosis
Neurologic	No underlying cause
Nutritional / Metabolic	No underlying cause
Obstetric/Gynecologic	No underlying cause
Oncologic	No underlying causes
Opthalmologic	No underlying causes
Overdose / Toxicity	Diethylpropion, monocrotaline, phentermine, radiation exposure (fibrosing mediastinitis and pulmonary fibrosis).
Psychiatric	No underlying causes
Pulmonary	Idiopathic pulmonary haemosiderosis, sarcoidosis, primary pulmonary hypertension, pulmonary fibrosis, alveolar capillary dysplasia with misalignment of pulmonary veins, Cystic fibrosis, Pulmonary embolism, tropical pulmonary eosinophilia, Pulmonary capillary hemangiomatosis, bronchiectasis,bronchopulmonary dysplasia, chronic obstructive pulmonary disease, pulmonary alveolar microlithiasis, pulmonary fibrosis, Langerhans cell histiocytosis,interstitial Lung Disease.
Renal / Electrolyte	Chronic renal failure on dialysis
Rheum / Immune / Allergy	No underlying causes
Sexual	No underlying causes
Trauma	No underlying causes
Urologic	No underlying causes
Miscellaneous	Gaucher disease, glycogen storage diseases, idiopathic spinal scoliosis,

Related Chapters

Congestive cardiac failure