Rheumatic Heart Disease Most Commonly Affects These Heart Valves

Rheumatic heart disease (RHD) typically develops as a consequence of untreated or inadequately treated infections caused by group A Streptococcus bacteria. Following an initial infection, such as strep throat or scarlet fever, the body's immune response can mistakenly attack the heart tissues, particularly the heart valves and endocardium. In the early stages, this condition may manifest as rheumatic fever, characterized by inflammation and various systemic symptoms. Once the heart becomes involved, it can lead to long-term structural damage to the cardiac anatomy.

The Four Heart Valves and Their Roles

The human heart consists of four major valves: the mitral valve, tricuspid valve, aortic valve, and pulmonary valve. Each of these valves plays a crucial role in ensuring the unidirectional flow of blood through the heart chambers and into the circulatory system. However, in cases of rheumatic heart disease, some valves are more frequently affected than others.

Why the Mitral Valve Is Most Commonly Affected

Statistically, the mitral valve is the most commonly affected valve in rheumatic heart disease, accounting for approximately 70% of cases. The mitral valve is located between the left atrium and the left ventricle, making it a key component in the left side of the heart. Due to its position and function, it is particularly vulnerable to the inflammatory processes triggered by rheumatic fever.

Combined Involvement of the Mitral and Aortic Valves

In about 30% of cases, the mitral valve may be affected alongside the aortic valve. The aortic valve controls blood flow from the left ventricle into the aorta and the systemic circulation. Because both the mitral and aortic valves are part of the left-sided heart system, they are often impacted together during rheumatic episodes. This dual involvement can lead to more complex clinical presentations and may require more intensive medical or surgical management.

Tricuspid and Pulmonary Valve Involvement Is Rare

While the tricuspid and pulmonary valves can also be affected in rheumatic heart disease, such cases are relatively rare. The tricuspid valve, located between the right atrium and right ventricle, may be involved in a small percentage of patients. Simultaneous involvement of both the tricuspid and pulmonary valves is even less common, likely due to their location in the right side of the heart, which is less frequently targeted by the immune-mediated damage associated with rheumatic fever.

Conclusion

Understanding which heart valves are most commonly affected by rheumatic heart disease is essential for early diagnosis and effective treatment. Since the mitral valve is most frequently involved, followed by the aortic valve in combination cases, healthcare providers should focus on monitoring these areas closely in patients with a history of rheumatic fever. Early detection and intervention can significantly improve long-term outcomes for individuals living with this chronic condition.