Cardiac Physiology 3

Question 1

3 measures of cardiac function

Answer 1

ejection fraction. stroke volume. cardiac output

Question 2

ejection fraction

Answer 2

% of ventricular volume pumped out in systole

Question 3

how to calculate ejection fraction for LV

Answer 3

LVEF = (LVEDV - LVESV)/LVEDV –> X100 %

Question 4

normal LV ejection fraction is?

Answer 4

> 50% (~55 - 60%)

Question 5

stroke volume and how to calculate

Answer 5

amount of blood pumped in each heart cycle –> end diastolic minus end systolic

Question 6

normal stroke volume

Answer 6

at least 60 mL per heart beat

Question 7

cardiac output is what? how to calculate?

Answer 7

amount of blood ejected over a certain period of time –> CO = stroke volume X heart rate

Question 8

chronotropy is what? accounts for ___% of?

Answer 8

how fast your heart is beating –> initial increases in cardiac output is 90% due to just a faster HR

Question 9

CO vs. HR relationship? until - what happens if your heart rate is too fast?

Answer 9

increase HR increases CO, until a certain point. too fast: systole time stays the same, diastole shortens = not enough time to fill = lower preload = lower stroke volume = lower cardiac output

Question 10

effects of adrenaline on cardiac output

Answer 10

increase heart rate, contractility/ejection fraction/stroke volume, lusitropy/time to fill LV/maintains preolad = increase CO. but it increases BP so increases afterload = decrease CO.

Question 11

factors that affect cardiac function overview

Answer 11

preload and contractility increase, afterload decreases stroke volume. stroke volume and heart rate determine CO