Question

Assume that the left ventricle of a child's heart has an EDV=90mL, and ESV=60mL, and a cardiac output of 2,400 mL/min. His SV is __________ mL/beat and his HR is __________ bpm.

A. 30; 80
B. 40; 60
C. 80; 30
D. 150; 16
E. 16; 150

Answer 1

The stroke volume (SV) is 30 mL/beat, calculated by EDV - ESV. The heart rate (HR) is 80 bpm, found by dividing the cardiac output by the stroke volume. The correct answer is A: SV = 30 mL/beat and HR = 80 bpm.

Step-by-step explanation:

The student's question is asking to calculate the stroke volume (SV) and heart rate (HR) given the end-diastolic volume (EDV), end-systolic volume (ESV), and cardiac output (CO). Stroke volume is calculated by subtracting the end-systolic volume from the end-diastolic volume (SV = EDV - ESV). Given the values EDV = 90 mL and ESV = 60 mL, the stroke volume (SV) would be 30 mL/beat. To find the heart rate, we use the formula for cardiac output which is CO = SV × HR. Since the cardiac output is given as 2,400 mL/min, we can rearrange this to HR = CO / SV. So, the heart rate (HR) would be 2,400 divided by 30, which is 80 bpm. Therefore, the correct answer is A: SV = 30 mL/beat and HR = 80 bpm.