Question

Compared to a normal heart, in left heart failure, why does ESV and EDV increase?

Answer 1

- In left heart failure, the left ventricle is unable to pump optimum amount of blood into the systemic circulation.

- End systolic volume (ESV) is the amount of blood remaining in ventricle at the end of its systole (contraction). It is usually around 50 ml in normal healthy heart. In left heart failure, the left ventricle is unable to pump adequate amount of blood into the systemic circulation hence greater amount of blood remains at the end of ventricular systole thus increasing the end systolic volume.

- End diastolic volume (EDV) is the amount of blood which remains in the ventricle at the end of ventricular diastole. Normally, it is around 120 ml. In left heart failure, the end diastolic volume is increased as the end systolic volume is already increased due to inadequate pumping of the left ventricle and in addition to this more blood is pumped from atria into the ventricles during atrial contraction and ventricular relaxation which further increases the end diastolic volume.

Thus, in left heart failure, both end systolic volume and end diastolic volume increases due to inadequate pumping of blood from the left ventricle into the systemic circulation.