Causes of Right-Sided Heart Failure
Right-sided heart failure (RHF) is primarily caused by left-sided heart disease, pulmonary vascular disease, primary myocardial disease, congenital heart disease, and volume or pressure overload conditions. 1, 2
Primary Causes of Right-Sided Heart Failure
1. Left-Sided Heart Disease
- Most common cause of elevated pulmonary artery pressures leading to RHF 2
- Includes:
- Coronary artery disease and left ventricular ischemia
- Hypertensive heart disease
- Left-sided valvular heart disease (mitral/aortic)
- Left ventricular cardiomyopathies
- Myocarditis affecting the left ventricle
2. Pulmonary Vascular Disease
- Pulmonary arterial hypertension (PAH)
- Pulmonary embolism (acute or chronic thromboembolic disease)
- Hypoxic pulmonary vasoconstriction from:
- Chronic obstructive pulmonary disease (COPD) - most frequent cause of cor pulmonale 3
- Interstitial lung disease
- Sleep-disordered breathing
- Pulmonary veno-occlusive disease
3. Primary Right Ventricular Dysfunction
- RV ischemia and infarction
- Arrhythmogenic right ventricular cardiomyopathy
- RV myocarditis
- Post-cardiotomy shock following cardiac surgery 1
4. Congenital Heart Disease
- Atrial septal defects
- Ventricular septal defects
- Eisenmenger syndrome
- Tetralogy of Fallot
- Ebstein's anomaly
5. Volume Overload Conditions
- Tricuspid regurgitation
- Pulmonary regurgitation
- Atrial septal defects with left-to-right shunting
6. Pressure Overload Conditions
- Pulmonary stenosis
- RV outflow tract obstruction
Pathophysiological Mechanisms
The right ventricle is uniquely vulnerable to increases in afterload due to its thin wall and coupling to the low-resistance pulmonary circulation 1:
Acute RV failure mechanisms:
- Abrupt increases in RV afterload (e.g., pulmonary embolism)
- Decreased RV contractility (RV ischemia, myocarditis)
- RV dilation promoting tricuspid regurgitation
- Ventricular interdependence causing leftward septal shift
Chronic RV failure progression:
- Initial adaptive RV hypertrophy
- Right atrial dilation and diastolic dysfunction
- Progressive RV dilation and systolic dysfunction
- RV-pulmonary arterial uncoupling 4
Clinical Manifestations
The clinical syndrome of RHF includes:
- Elevated jugular venous pressure
- Peripheral edema
- Congestive hepatomegaly
- Ascites in advanced cases
- Exercise intolerance and dyspnea
- Decreased cardiac output 5
Diagnostic Considerations
When evaluating for causes of right-sided heart failure:
- Echocardiography with bubble study to evaluate for shunts and RV function
- Pulmonary function tests to assess for underlying lung disease
- V/Q scan or CT angiogram if thromboembolic disease is suspected
- Sleep study to evaluate for sleep-disordered breathing
- Right heart catheterization for definitive hemodynamic assessment 2
Clinical Pearls and Pitfalls
- Even mildly elevated pulmonary artery pressures are associated with poor outcomes and should not be ignored 2
- The RV is more sensitive to afterload increases than the LV, with stroke volume declining steeply with pressure increases 1
- RV failure worsens left ventricular hemodynamics through ventricular interdependence 3
- RV ejection fraction <40% is an important predictor of poor prognosis after myocardial infarction 3
- Early recognition of RHF and identifying the underlying etiology are crucial for effective treatment 5
Understanding these diverse causes of right-sided heart failure is essential for appropriate diagnosis, management, and improving outcomes in affected patients.