During pregnancy, which change occurs in the heart?

During pregnancy, which change occurs in the heart?

• A. Decrease in LV end-systolic volume
• B. Decrease in ejection fraction
• C. Increase in LV end-diastolic volume
• D. Decrease in heart rate

Answer: (C)

During pregnancy the circulatory system expands blood volume significantly, which raises venous return to the heart. This increased preload causes the left ventricle to fill more during diastole, so the end-diastolic volume rises. To handle the higher preload, the heart undergoes mild dilation and the stroke volume and cardiac output increase, while ejection fraction remains preserved. Heart rate also tends to rise rather than fall. End-systolic volume is governed by contractility and afterload and does not typically decrease in a way that would account for the change described above. So the notable change is an increase in LV end-diastolic volume.

During pregnancy the circulatory system expands blood volume significantly, which raises venous return to the heart. This increased preload causes the left ventricle to fill more during diastole, so the end-diastolic volume rises. To handle the higher preload, the heart undergoes mild dilation and the stroke volume and cardiac output increase, while ejection fraction remains preserved. Heart rate also tends to rise rather than fall. End-systolic volume is governed by contractility and afterload and does not typically decrease in a way that would account for the change described above. So the notable change is an increase in LV end-diastolic volume.