Dobutamine's effect on LVEDP and LVEDV is best described as which?

Dobutamine's effect on LVEDP and LVEDV is best described as which?

• A. LVEDP increases due to increased LVEDV
• B. LVEDP decreases due to decreased LVEDV
• C. LVEDP unchanged with increased LVEDV
• D. LVEDP increases while LVEDV decreases

Answer: (B)

Dobutamine boosts heart muscle contractility through beta-1 stimulation, which makes the ventricle pump more effectively. As a result, more blood is ejected during systole and the amount of blood remaining at the end of filling is reduced. With a more forceful, efficient contraction, the ventricle doesn’t need as much volume to reach a given diastolic pressure, so the end-diastolic volume falls and, in a compliant ventricle, the end-diastolic pressure falls as well. That’s why the best description is a decrease in LVEDP driven by a decrease in LVEDV.

Dobutamine boosts heart muscle contractility through beta-1 stimulation, which makes the ventricle pump more effectively. As a result, more blood is ejected during systole and the amount of blood remaining at the end of filling is reduced. With a more forceful, efficient contraction, the ventricle doesn’t need as much volume to reach a given diastolic pressure, so the end-diastolic volume falls and, in a compliant ventricle, the end-diastolic pressure falls as well. That’s why the best description is a decrease in LVEDP driven by a decrease in LVEDV.