What is the primary consequence of mitral valve prolapse during systole?
Solution
Correct Answer: Option A
- The primary consequence of mitral valve prolapse (MVP) during systole is the regurgitation of blood into the left atrium.
- During systole, the left ventricle contracts to pump blood into the aorta.
- In a normal heart, the mitral valve leaflets close tightly to prevent backflow.
- However, in mitral valve prolapse, one or both of the mitral valve leaflets abnormally bulge (prolapse) back into the left atrium.
- This improper closure leads to incompetence of the valve, allowing blood to flow backward — a phenomenon known as mitral regurgitation.
- This regurgitant flow increases the volume load on the left atrium and can cause symptoms such as palpitations, fatigue, or even arrhythmias in some cases.
- Over time, significant regurgitation may lead to left atrial enlargement and eventually impact left ventricular function.
To clarify why the other options are incorrect:
- Option 2 (Reduced blood flow into the aorta) is not the primary consequence; while severe mitral regurgitation may indirectly reduce forward stroke volume, the initial issue is regurgitation, not obstruction.
- Option 3 (Increased pressure in the right ventricle) is not directly related to MVP since the pathology primarily involves the left side of the heart.
- Option 4 (Obstruction of pulmonary venous return) is unrelated to mitral valve prolapse.
In summary, the hallmark of mitral valve prolapse during systole is regurgitation of blood back into the left atrium due to improper closure of the mitral valve leaflets.
Reference: Cardiovascular Physiology, 12th Edition, Chapter 9: Valvular Heart Disease / Page 278
- During systole, the left ventricle contracts to pump blood into the aorta.
- In a normal heart, the mitral valve leaflets close tightly to prevent backflow.
- However, in mitral valve prolapse, one or both of the mitral valve leaflets abnormally bulge (prolapse) back into the left atrium.
- This improper closure leads to incompetence of the valve, allowing blood to flow backward — a phenomenon known as mitral regurgitation.
- This regurgitant flow increases the volume load on the left atrium and can cause symptoms such as palpitations, fatigue, or even arrhythmias in some cases.
- Over time, significant regurgitation may lead to left atrial enlargement and eventually impact left ventricular function.
To clarify why the other options are incorrect:
- Option 2 (Reduced blood flow into the aorta) is not the primary consequence; while severe mitral regurgitation may indirectly reduce forward stroke volume, the initial issue is regurgitation, not obstruction.
- Option 3 (Increased pressure in the right ventricle) is not directly related to MVP since the pathology primarily involves the left side of the heart.
- Option 4 (Obstruction of pulmonary venous return) is unrelated to mitral valve prolapse.
In summary, the hallmark of mitral valve prolapse during systole is regurgitation of blood back into the left atrium due to improper closure of the mitral valve leaflets.
Reference: Cardiovascular Physiology, 12th Edition, Chapter 9: Valvular Heart Disease / Page 278
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