Question

Find out the cardiac output, if heart rate is \[75\,times\,{\min ^{ - 1}}\]. EDV (End Diastolic Volume) = 150 ml and ESV (End Systolic Volume) = 60 ml.
(A) $6750\,ml$
(B) $6000\,ml$
(C) $4500\,ml$
(D) $11250\,ml$

Answer 1

Hint: Use the formula of the stroke volume to calculate the amount of the blood that passes through the ventricle per minute. By using this obtained value of stroke volume, calculate the value of the cardiac output by using its formula. This result gives the amount of blood pumped by the heart per minute.

Formula used:
(1) The cardiac output is calculated as
$co = r \times sv$
Where, the co is the cardiac output, r is the rate of the heart beat per minute and the sv is the stroke volume of the blood.
(2) The stroke volume of the blood is calculated as
sv = EDV - ESV
Where, the EDV is the end diastolic volume and the ESV is the end systolic volume.

Complete Answer:
The cardiac output is defined as the quantity of the blood that is pumped by the heart through the circulatory system in one minute of the time. It mainly depends upon the rate of the heart beat and also the volume of the blood passes through the ventricle per minute.
Calculating the stroke volume using the formula (2)
sv = EDV - ESV
sv = 150 - 60

By performing the subtraction,
$sv = 90\,ml$
Substituting the value of the stroke volume in the cardiac output formula
$co = r \times sv
co = 75 \times 90
The cardiac output obtained is
co = 6750\,ml$

Thus the option (A) is correct.

Note: The end systolic volume is the quantity of the blood that remains in the ventricle at the time of the contraction. And the end diastolic volume is the volume of the blood at the end of the expansion. The volume of the blood in the ventricle at the end diastole is always greater than that of the systole.