Right Heart Failure: Causes and Mechanisms

Introduction

Right heart failure (RHF) occurs when the right ventricle loses its ability to effectively pump blood to the lungs. This leads to systemic venous congestion and symptoms such as leg swelling, abdominal distension, and fatigue. Understanding the main causes of RHF is essential for proper diagnosis and treatment.

Main Causes of Right Heart Failure

1. Left-Sided Heart Failure

• The most common cause of RHF.
• When the left ventricle fails, blood backs up into the lungs, increasing pulmonary pressure. This excessive pressure overloads the right ventricle, eventually leading to failure.

2. Pulmonary Hypertension

• Increased pressure in the pulmonary arteries forces the right ventricle to work harder.
• Over time, the right ventricle hypertrophies (thickens) and eventually fails.

3. Chronic Lung Diseases (Cor Pulmonale)

• Conditions like chronic obstructive pulmonary disease (COPD), interstitial lung disease, and sleep apnea can increase pulmonary artery pressure and strain the right ventricle.

4. Right Ventricular Myocardial Infarction

• A heart attack specifically affecting the right ventricle impairs its function.
• This can lead to acute RHF, especially following inferior myocardial infarctions.

5. Congenital Heart Diseases

• Defects like Tetralogy of Fallot, Ebstein’s anomaly, and Eisenmenger syndrome can cause longstanding right ventricular overload and failure.

6. Pulmonary Embolism (Acute Cause)

• A large clot blocking the pulmonary arteries suddenly increases pressure in the right ventricle.
• In massive cases, it can rapidly lead to life-threatening RHF.

7. Tricuspid Valve Disease

• Tricuspid regurgitation (leaking valve) or tricuspid stenosis (narrowed valve) can cause volume overload or increased resistance, eventually leading to right ventricular dysfunction.

8. Cardiomyopathies Affecting the Right Ventricle

• Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic condition leading to right ventricular dysfunction.
• Restrictive cardiomyopathies can also strain the right heart chambers.

Conclusion

Right heart failure typically results from increased stress on the right ventricle caused by lung disease, elevated pulmonary pressures, left heart failure, or intrinsic right ventricular pathologies. A proper diagnosis requires clinical evaluation, imaging (echocardiography, MRI), and laboratory tests. Managing RHF involves treating the underlying cause while addressing symptoms to improve quality of life.

Source recommendations

1. American Heart Association Guidelines on Heart Failure

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001063
2. https://www.heart.org/en/health-topics/heart-failure
3. https://professional.heart.org/en/guidelines-and-statements
4. https://www.heart.org/en/health-topics/heart-failure/what-is-heart-failure/classes-of-heart-failure
5. https://professional.heart.org/en/science-news/-/media/832EA0F4E73948848612F228F7FA2D35.ashx

2. European Society of Cardiology Guidelines on Heart Failure

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Acute-and-Chronic-Heart-Failure
2. https://academic.oup.com/eurheartj/article/42/36/3599/6358045
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Focused-Update-on-Heart-Failure-Guidelines
4. https://academic.oup.com/eurheartj/article/44/37/3627/7246292
5. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines

3. ESC/ERS Guidelines on Pulmonary Hypertension

1. https://academic.oup.com/eurheartj/article/43/38/3618/6673929
2. https://publications.ersnet.org/content/erj/early/2022/08/25/1399300300879-2022.abstract
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Pulmonary-Hypertension-Guidelines-on-Diagnosis-and-Treatment-of
4. https://pubmed.ncbi.nlm.nih.gov/36017548/
5. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2022/08/30/19/11/2022-ESC-Guidelines-for-Pulmonary-Hypertension-ESC-2022