Question

What would be the heart rate of a person if the cardiac output is 5 L, blood volume in the ventricles at the end of diastole is 100 mL and at the end of ventricular systole is 50 mL?

• A. 125 beats per minute
• B. 50 beats per minute
• C. 75 beats per minute
• D. 100 beats per minute

Answer 1

The correct option is D 100 beats per minute

Stroke volume = End diastolic volume – End systolic volume
$=100–50=50\text{mL}$
Given here, cardiac output $=5\text{L}$ $=5000\text{mL}$
Since, Cardiac output = Heart beat $\times$ stroke volume,
Heart beat $=\frac{\text{Cardiac output}}{\text{Stroke volume}}$
$=\frac{5000}{50}=100\text{beats per minute}$