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288.e2 Eisenmenger’s Syndrome

Eisenmenger’s Syndrome Client Education
Sheet
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• Tachycardia
BASIC INFORMATION
○ Pulmonic stenosis
• Tachypnea • Echocardiographic
Definition • Generalized or regional cyanosis (segmental ○ Tetralogy of Fallot
Uncommon syndrome involving any large or differential cyanosis occurs with a right-to- ○ Heartworm disease
communication between the left and right left PDA because deoxygenated blood shunts
sides of the heart in association with severe to the hind end), depending on underlying Initial Database
pulmonary hypertension, which results in cause • CBC: erythrocytosis (usually progressive with
right-to-left shunting of blood • Loud second heart sound age)
• Split second heart sound • Heartworm test: antigen, antibody (cats),
Synonyms and microfilaria tests
• Eisenmenger’s physiology or reaction Etiology and Pathophysiology • Thoracic radiographs: right heart enlarge-
• Eisenmenger’s complex: large, nonrestric- • Size of the defect and severity of PH ment, enlarged main pulmonary artery,
tive ventricular septal defect (VSD) plus determine the degree of shunting and the normal to mildly enlarged pulmonary
pulmonary hypertension causing right-to-left occurrence and extent of clinical signs. vasculature
shunting with or without dextroposition of ○ Hypoxemia from shunting of venous blood • Systemic arterial blood pressure measurement:
the aorta into the arterial circulation leads to eryth- hypotension contraindicates performing
• Cyanotic congenital heart disease includes ropoietin production and erythrocytosis. phlebotomy without fluid replacement.
Eisenmenger’s syndrome and right-to-left ○ Erythrocytosis, if severe, can produce • Electrocardiogram: tall P waves in lead II,
cardiac shunts without pulmonary hyperten- hyperviscosity and pulmonary embo- deep S waves in lead II, right axis deviation;
sion (e.g., VSD with concurrent pulmonic lism, central neurologic signs, and/or arrhythmias are uncommon
stenosis) coagulopathies. • Echocardiogram
• Congenital ○ 2D: right ventricular hypertrophy, enlarged
Epidemiology ○ High pulmonary vascular resistance is main pulmonary artery, identification of
SPECIES, AGE, SEX maintained after birth. structural defects
• Dogs and cats ○ Abnormal maturation of the pulmonary ○ M mode: right ventricular free wall and
• Young animals vasculature septal hypertrophy, septal flattening,
• Female dogs more predisposed to patent • Acquired paradoxical septal motion
ductus arteriosus (PDA); up to 15% of dogs ○ Large systemic-pulmonary communica- ○ Color flow Doppler: aliased or laminar
with PDA can have pulmonary hypertension tion (left-to-right shunt) offers minimal flow across the congenital defect, tricuspid
resistance to systolic flow. regurgitation (uncommon)
GENETICS, BREED PREDISPOSITION ○ Relative flows are determined by systemic ○ Spectral Doppler: tricuspid regurgitant
Depends on the underlying cause: and pulmonary vascular resistance. velocity > 3.5 m/s, pulmonic insufficiency
• PDA: quasicontinuous or threshold trait ○ Prolonged PH leads to pulmonary vas- velocity > 3 m/s, reversed E/A ratio of
with high degree of heritability. Miniature cular disease, an abnormal maturation mitral valve inflow profile, midsystolic
and toy poodles, collie, Pomeranian, Shetland of the pulmonary vasculature, and right notching of the pulmonary flow profile
sheepdog, American cocker spaniel, German ventricular hypertrophy. (severe cases)
shepherd, Maltese, keeshond, Yorkshire terrier ○ Pulmonary arterial histologic features with ○ Contrast echo: contrast appears in the left
• VSD: autosomal-dominant trait with PH: medial muscular hypertrophy, laminar heart (intracardiac shunt such as right-
incomplete penetrance or a polygenic trait. intimal fibrosis, necrotizing arteritis, to-left VSD) or in the abdominal aorta
English springer spaniel, English bulldog plexiform lesions (extracardiac shunt such as right-to-left
○ With progression, pulmonary vascular PDA).
RISK FACTORS resistance may increase to a value greater
Living at high altitude (pulmonary hypertension than the systemic vascular resistance, Advanced or Confirmatory Testing
[PH]) causing right-to-left or bidirectional • Cardiac catheterization: used for confirming
shunting (mixing of venous and arterial diagnosis and to assess degree of shunting
ASSOCIATED DISORDERS blood). ○ Angiogram: outlines the congenital
Eisenmenger’s syndrome can originate from defect(s) (PDA, VSD, ASD, or aortico-
an isolated cardiac defect (e.g., PDA) or from DIAGNOSIS pulmonary communication)
a combination of VSD or atrial septal defect ○ Pressure measurements: increased pulmo-
(ASD) and PDA. Diagnostic Overview nary artery pressures. With large defects,
The diagnosis is suspected in a young patient right and left ventricular pressures have
Clinical Presentation presenting with dyspnea, cyanosis, and col- a tendency to equalize.
HISTORY, CHIEF COMPLAINT lapsing episodes. Erythrocytosis and right • Oximetry: decreased aortic PO 2
• Dyspnea (most common sign in cats) heart enlargement are usually present. An • Transesophageal echocardiography: better
• Exercise intolerance echocardiogram with contrast is required for visualization of the congenital defect
• Syncope confirmation (p. 1094).
• Lethargy TREATMENT
• Cough Differential Diagnosis
• Cyanosis • Radiographic/electrocardiographic Treatment Overview
• Hind limb collapse ○ Right heart enlargement: other types of Initial control of erythrocytosis and signs of
cardiac disease (pulmonic stenosis, tetral- hyperviscosity can be achieved with periodic
PHYSICAL EXAM FINDINGS ogy of Fallot, heartworm disease, tricuspid phlebotomies. Hydroxyurea (a myelosuppressive
• Heart murmur (timing and location deter- valve dysplasia, atrial septal defect), cor agent) and a phosphodiesterase-5 inhibitor
mined by defect[s] present) pulmonale (to reduce severity of PH) may be started
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