Right Ventricle Enlargement

Alexander J. Towbin, MD

DIFFERENTIAL DIAGNOSIS

Common

Pulmonary Hypertension (PH)
Atrial Septal Defect (ASD)

Less Common

Dilated Cardiomyopathy
Pulmonary Stenosis
Pulmonary Thromboembolism (PTE)

Rare but Important

Tricuspid Regurgitation

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Causes: ↑ pulmonary vascular resistance, ↑ right heart blood volume

Helpful Clues for Common Diagnoses

Pulmonary Hypertension (PH)
- In neonatal period, persistent PH of newborn is most common cause of PH
  - Association: Neonatal lung disorders → increased pulmonary vascular resistance
- Causes of PH in children: Congenital heart defect (CHD) and pulmonary disease
- Occurs in CHD when pulmonary blood flow or vascular resistance is ↑
- Main pulmonary artery is larger than aorta
Atrial Septal Defect (ASD)
- 2nd most common isolated CHD
- 3 types: Secundum (92.5%), primum, and sinus venosus
- MR: Differentiated from normal wall thinning by thickening at edge of defect

Helpful Clues for Less Common Diagnoses

Dilated Cardiomyopathy
- Typical dilated ventricles & ↓ contractility
- Often presents with heart failure
- Multiple etiologies: Viral myocarditis, CHD, Takayasu arteritis, metabolic disorders, and nutritional deficiencies
- Most often thought to be idiopathic
- CXR: Cardiomegaly and pulmonary congestion
Pulmonary Stenosis
- Types: Valvular, subvalvular, supravalvular, or in branch pulmonary arteries
- Valvular most common (7-9% of all CHD)
  - CXR: Dilated main pulmonary artery
Pulmonary Thromboembolism (PTE)
- Uncommon in children
- Risk factors: Central venous lines, malignancy, CHD, lupus, vascular malformations, or renal disease
- 30-60% have deep vein thrombosis
- Chronic PTE → right heart failure and PH

Helpful Clues for Rare Diagnoses

Tricuspid Regurgitation
- Can be seen as part of Ebstein anomaly or as isolated anomaly
- Isolated tricuspid regurgitation can be caused by papillary muscle rupture
  - Rare cause in children
  - Papillary rupture can occur in utero

Image Gallery

AP radiograph of the chest shows complete consolidation of the right hemithorax with a rightward shift of the heart and mediastinum due to pulmonary hypoplasia. The left hilum is enlarged