What is the primary purpose of a diuretic in congestive heart failure due to mitral valve disease?

• A. Reduce preload
• B. Increase heart rate
• C. Increase afterload
• D. Decrease stroke volume

Answer: (A)

In congestive heart failure from mitral valve disease, the main problem is fluid overload that raises filling pressures and backs up blood into the lungs. A diuretic’s primary job is to remove excess fluid, which lowers the amount of blood returning to the heart (the preload). With less preload, the left atrial and pulmonary venous pressures drop, easing pulmonary congestion and edema and improving breathing and overall comfort.

This approach directly targets the symptom-causing congestion seen in mitral valve disease without primarily altering heart rate or changing afterload. It also doesn’t aim to decrease stroke volume as a goal; its purpose is to relieve the excessive filling pressures that drive edema and breathlessness.