Semilunar Valves in the Heart

Introduction

The heart is a highly efficient pump that ensures continuous blood circulation throughout the body. Among its key structures are the semilunar valves, which play a crucial role in regulating blood flow and preventing backflow.

What Are Semilunar Valves?

The heart has two semilunar valves:

• Aortic Valve – Located between the left ventricle and the aorta, it allows oxygen-rich blood to pass into the aorta and prevents its return.
• Pulmonary Valve – Positioned between the right ventricle and the pulmonary artery, it allows deoxygenated blood to be sent to the lungs and prevents backflow into the heart.

Function of Semilunar Valves

When the ventricles contract (systole), these valves open to let blood flow into major arteries (aorta and pulmonary arteries). When the ventricles relax (diastole), the valves close to prevent the blood from returning to the heart. This function ensures one-way blood circulation and maintains proper pressure within the heart chambers.

Common Disorders of Semilunar Valves

1. Aortic Stenosis

• The aortic valve becomes narrowed, restricting blood flow.
• Symptoms: Chest pain, breathlessness, dizziness.
• Treatment: May require valve replacement.

2. Aortic Regurgitation

• The aortic valve does not close properly, allowing blood to leak back.
• Symptoms: Fatigue, palpitations, heart failure symptoms in severe cases.
• Treatment: Can be managed with medication or surgery if severe.

3. Pulmonary Stenosis

• The pulmonary valve is narrowed, causing strain on the right ventricle.
• Symptoms: Fatigue, shortness of breath, cyanosis (bluish skin in severe cases).
• Treatment: Balloon valvuloplasty or surgery in severe cases.

4. Pulmonary Regurgitation

• The pulmonary valve does not close properly, allowing backflow into the right ventricle.
• Often associated with congenital heart defects or pulmonary hypertension.
• Treatment: Usually mild but may require valve replacement in severe cases.

Conclusion

Semilunar valves are essential for efficient blood circulation. Their proper functioning ensures that the heart operates smoothly. If problems arise, early detection and management lead to better outcomes. Regular check-ups with a cardiologist and echocardiography can help detect valve disorders in time.

Source recommendations

1. 2021 European Society of Cardiology (ESC) Guidelines on Valvular Heart Disease

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Valvular-Heart-Disease-Guidelines
2. https://academic.oup.com/eurheartj/article/43/7/561/6358470
3. https://pubmed.ncbi.nlm.nih.gov/34453165/
4. https://eurointervention.pcronline.com/article/2021-esc-eacts-guidelines-for-the-management-of-valvular-heart-disease
5. https://www.jacc.org/doi/10.1016/j.jacc.2023.05.061

2. 2020 American College of Cardiology (ACC)/American Heart Association (AHA) Guidelines for the Management of Patients with Valvular Heart Disease

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000923
2. https://pubmed.ncbi.nlm.nih.gov/33332149/
3. https://www.jacc.org/doi/10.1016/j.jacc.2020.11.035
4. https://pubmed.ncbi.nlm.nih.gov/33342586/
5. https://professional.heart.org/en/science-news/2020-acc-aha-guideline-for-the-management-of-patients-with-valvular-heart-disease