Cardiovascular calculations: Peter is wearing a cardiovascular monitoring device
ID: 3476028 • Letter: C
Question
Cardiovascular calculations: Peter is wearing a cardiovascular monitoring device during his rowing competition. He is at the 1000 meter mark (halfway through), and his device is reading the following data: PARAMETER Systolic pressure (aorta) Diastolic pressure (aorta) R-R interval Left ventricular EDV Left ventricular ESV Mean pulmonary artery pressure Right atrial pressure Left atrial pressure O2 consumption (whole body) O2 content of systemic arterial blood O2 content of pulmonary arterial blood VALUE 170 mm Hg 80 mm Hg 470 msec 180 mL 50 mL 21 mmHg 3 mm Hg 6 mmHg 1500 mL/min 0.20 mL O2/mL blood 0.11 mL O2/mL bloodExplanation / Answer
Stroke volume is the amount of blood pumped per heart beat. It is calculated by subtracting end systolic volume from end diastolic volume,
= EDV - ESV
= 180 - 50
= 130 ml
Cardiac output is defined as the amount of blood pumped by the heart per minute. It is the product of stroke volume and heart rate. Heart rate can be calculated from R-R interval.
Heart rate = 60/RR interval
= 60/0.47
= 127
Cardiac output = stroke volume x heart rate
= 130 x 127
= 16540 ml
= 16.54 liters
Ejection fraction is a measure of amount of blood that is pumped out of heart per contraction. It is calculated as follows,
= Stroke volume/ end diastolic volume
= 130/180
= 72.22%