Milrinone lowers LV filling pressures due to which effect?

Milrinone lowers LV filling pressures due to which effect?

• A. Increased LV preload
• B. Increased LV end-diastolic volume
• C. Decreased LV filling pressures
• D. Decreased LV ejection fraction

Answer: (C)

Milrinone lowers LV filling pressures mainly by reducing preload through venous dilation. As a PDE-3 inhibitor, it raises cAMP in vascular smooth muscle, causing veins to dilate and pull more venous return away from the heart. That decreased venous return lowers the pressure the left ventricle must fill against (the LV filling pressure). At the same time, milrinone improves diastolic relaxation and increases systolic function, so it can raise ejection fraction rather than reduce it. Increasing preload or LV end-diastolic volume would raise filling pressures, not lower them, so those options don’t fit.

Milrinone lowers LV filling pressures mainly by reducing preload through venous dilation. As a PDE-3 inhibitor, it raises cAMP in vascular smooth muscle, causing veins to dilate and pull more venous return away from the heart. That decreased venous return lowers the pressure the left ventricle must fill against (the LV filling pressure). At the same time, milrinone improves diastolic relaxation and increases systolic function, so it can raise ejection fraction rather than reduce it. Increasing preload or LV end-diastolic volume would raise filling pressures, not lower them, so those options don’t fit.