Cardiology > Eisenmenger Syndrome   

Background 

I) Definition 

Eisenmenger syndrome is a late complication of uncorrected congenital heart defects with significant left-to-right shunting (e.g., ventricular septal defect, atrial septal defect, patent ductus arteriosus). Over time, the increased pulmonary blood flow causes pulmonary vascular remodeling, leading to pulmonary arterial hypertension (PAH). Once pulmonary pressures exceed systemic pressures, the shunt reverses to right-to-left, resulting in systemic hypoxemia and cyanosis. It represents a fixed, irreversible form of pulmonary hypertension with multisystem complications. 

II) Classification/Types 

By Underlying Defect: 

• • Ventricular Septal Defect (VSD) – Most common cause 

• • Atrial Septal Defect (ASD) 

• • Patent Ductus Arteriosus (PDA) 

• • Atrioventricular Septal Defect 

• • Complex cyanotic heart lesions (e.g., truncus arteriosus) 

By Clinical Features: 

• • Classic Eisenmenger Syndrome: Cyanosis, PAH, and erythrocytosis 

• • Latent Eisenmenger Physiology: Mild symptoms with subclinical hypoxemia 

• • Eisenmenger Complex: Refers to the primary VSD with PAH and shunt reversal 

Pathophysiology 

Initial left-to-right shunting increases pulmonary blood flow, leading to endothelial injury, vascular smooth muscle proliferation, and fibrosis in pulmonary arteries. Progressive pulmonary vascular resistance ultimately exceeds systemic vascular resistance, causing reversal of the shunt (right-to-left). The resulting hypoxemia and cyanosis lead to secondary erythrocytosis, hyperviscosity, coagulopathy, and end-organ damage. Vascular remodeling becomes irreversible, making late repair of the congenital defect ineffective or even harmful. 

Epidemiology 

• • Occurs in 5–10% of uncorrected congenital heart defects 

• • More common in resource-limited settings where early surgical intervention is delayed 

• • Slight female predominance 

• • Typically presents in adolescence or early adulthood if not surgically repaired in childhood 

Etiology 

I) Causes 

• • Long-standing uncorrected congenital left-to-right shunts 

• • VSD, ASD, PDA, AVSD, truncus arteriosus 

II) Risk Factors 

• • Delayed or missed diagnosis of congenital heart defects 

• • Limited access to pediatric cardiac surgery 

• • Genetic syndromes (e.g., Down syndrome with AVSD) 

• • Larger defect size and higher initial shunt volumes 

Clinical Presentation 

I) History (Symptoms) 

• • Exertional dyspnea and fatigue 

• • Central cyanosis (often first sign) 

• • Headaches, dizziness, or syncope 

• • Hemoptysis (from pulmonary artery rupture) 

• • Chest pain or angina (from RV ischemia) 

• • Stroke or paradoxical embolism 

• • Menstrual irregularities in females 

• • Pregnancy-related complications 

II) Physical Exam (Signs) 

• • Central cyanosis and digital clubbing 

• • Loud P2 (accentuated pulmonary component of S2) 

• • Right ventricular heave 

• • Systolic murmur from tricuspid regurgitation 

• • Peripheral edema, hepatomegaly (right heart failure signs) 

• • Signs of erythrocytosis (ruddy complexion, engorged conjunctiva) 

Differential Diagnosis (DDx) 

• • Primary pulmonary arterial hypertension 

• • Tetralogy of Fallot 

• • Pulmonary embolism 

• • Chronic obstructive pulmonary disease (COPD) with hypoxia 

• • Cyanotic congenital heart disease (e.g., transposition of the great arteries) 

Diagnostic Tests 

Initial Evaluation 

• • Pulse Oximetry: Persistent low saturations, worsened by exertion 

• • ECG: Right axis deviation, RV hypertrophy 

• • Chest X-ray: Enlarged pulmonary arteries, pruning of peripheral vasculature 

• • Transthoracic Echocardiography (TTE): Detects congenital defect, PAH, and RV changes 

• • Bubble study: May show delayed right-to-left shunting 

Advanced Imaging 

• • Cardiac MRI: Defines anatomy, quantifies shunt (Qp:Qs), assesses RV function 

• • CT Angiography: Evaluates pulmonary vasculature, rules out thromboembolism 

• • Right Heart Catheterization: Gold standard for PAH diagnosis; confirms elevated pulmonary pressures and shunt reversal 

Treatment 

I) Acute Management 

• • Oxygen supplementation (limited effectiveness but may help with symptoms) 

• • Phlebotomy (if hyperviscosity with symptoms) 

• • Treat heart failure with diuretics 

• • Manage arrhythmias 

• • Avoid high-altitude exposure, dehydration, excessive exertion 

II) Definitive/Long-Term Management 

• • Pulmonary vasodilator therapy: PAH-specific treatment 

• • Repair of congenital defect: Contraindicated once Eisenmenger physiology is established 

• • Lung or heart-lung transplantation: Option in end-stage cases 

• • Preventive measures: Vaccination, stroke prevention, and pregnancy avoidance 

Medications 

Device Therapy 

• • Implantable loop recorder: For syncope or arrhythmia workup 

• • Pacemaker: Rarely needed unless bradyarrhythmias develop 

• • Oxygen concentrators: For symptomatic relief during travel or activity 

Patient Education, Screening, Vaccines 

• • Avoid pregnancy: High maternal and fetal mortality 

• • Endocarditis prophylaxis: If prosthetic material or residual shunts present 

• • Vaccinations: Influenza, pneumococcal, COVID-19 

• • Avoid dehydration and high altitudes 

• • Educate on signs of stroke, hemoptysis, and worsening cyanosis 

Consults/Referrals 

• • Adult congenital cardiologist: Central to ongoing care 

• • Pulmonologist: For management of PAH 

• • Hematologist: If erythrocytosis or hyperviscosity 

• • Neurologist: For evaluation post-stroke or TIA 

• • Maternal-Fetal Medicine (MFM): If pregnancy occurs (high-risk counseling) 

Follow-Up 

Short-Term 

• • Baseline and periodic echocardiography or cardiac MRI 

• • Regular assessment of oxygenation, hematocrit, and functional status 

• • Monitor drug efficacy and side effects 

Long-Term 

• • Lifelong cardiology follow-up (every 6–12 months) 

• • Repeat right heart catheterization as indicated 

• • Monitor for progressive RV dysfunction, arrhythmias, and complications 

Prognosis 

• • Poor without specialized care 

• • • Median survival: ~30–40 years from symptom onset 

• • • PAH-targeted therapy has improved quality of life and survival 

• • • Risk of sudden cardiac death, hemoptysis, and paradoxical embolism remains 

• • • Early detection of congenital heart defects and timely repair is key to prevention