Cardiology - cardiac cycle Flashcards
What are the 2 main phases?
Propotion of each heart beat?
And what happens in them?
diastole - 2/3 heart beat
and ventricular relaxation (ventricles fill with blood)
systole - 1/3 heartbeat
ventricle contract, generate pressure eject blood
What are 3 stages of systole?
isovolumeitrc contraction, rapid ejection , slow ejection
when does end diastolic volume occur?
And what is it?
isovoulemic contraction
max volume before contract
what is end-sysotic volume?
when occur?
the residual volume (left over)
end of slow ejection
What is stroke V?
end diastolic volume(max)
-
end systolic volume (lowest)
how do you calculate ejection fraction?
stroke volume divide end diastolic volume
Cycle of the cardiac phases?
Name all the valves
RHS - Deoxygenated
triscuspid valves then pulmonary valves
LHS - oxygn
bicuspid valve then aortic valve
What happens in atrial systole?
atria almost full from passive filling
atria also contract to top of volume in ventricle
What happens in isovolumetric contraction?
ventricular depolarisation
between AV valves close + open of semi-lunar valves
contract of ventricles but no change in volume
when pressure V higher than A, AV valves close
What is the P wave on ECG?
atrial systole
What causes rapid ejection?
when ventricular pressure > than pulmonary and aorta artery
What happens in rapid ejection?
ventricle contract and pressure exceed artery pressure
semi lunar valves open
blood pumped out of ventricle
What happens in reduced rejection?
reduced pressure gradient semi-lunar valves close
decreased blood flow and ventricular volume decreases less
blood flows back and semilunar valve close
What happens in isovolumetric relaxation?
Av remain closed until ventricular pressure drops below atrial
atrial pressure increase
aorta pressure increases
What is dichrotic notch?
Aorta increasing pressure in volumetric relaxation
due to rebound pressure
What happens in rapid passive feeling?
AV valves open and blood flow into ventricles
What is reduced passive filling?
diastasis
ventricle volume fills slowly but still able to fill a lot before contraction from atria
What is P wave?
atrial systole
When is 4th hear sound?
Is it normal?
atrial systole
no, occurs with congestive heart failure and pulmonary and tricsupid incompetnece
When does 1st (lub) occur?
Why?
isovolumetric contraction
due to closure of AV valves
Does rapid ejection have a heart sound?
NO
Does opening of valves make a sound?
No, only closing
What cardiac phase is respented by T wave?
reduced ejecction
ventricular muscles muscles repolarize produced T waves
as end of depolarisaton
What signifies QRS?
start of ventricular depolarisation
isovolumetric contraction
When does dub occur?
(2nd heart sound)
close semi-lunar valves
isovolumetric relaxation
When does 3rd heart sound occur?
Is it normal?
rapid passive filling
abonrla due to turbulent ventricular filling
show hypertension or mitral incompetence
Are the patterns of pressure changes between of right and left heart same? If not why?
YES same pattern of CHANGES is same, as in time of changes
Which side of heart has higher pressure?
right lower than left as going to lungs
What is differences in volume ejected by each side?
SAME volume of blood ejected, but right lower pressure circuit
What is pressure difference in systemic and pulmonary circuits? (i.e ateries, cappilarties
Draw a ventricular volume (x) vs ventricular pressure (y) graph?
What is preload?
Blood fillling ventricules during diasotle + streches it
What is after load?
Ejection of blood into artieres, after isovulemtic pressure
How does the LOOP fit in with pressure/muscle length fibre graph?
What affect does preload have on volumes?
increased in PRELOAD
increases STROKE volume
What happens when we increase diatole pressure?
greater pressure required to open aortic valve
less shorterning of muscles as working against increased afterload
increases afterload decreased stroke volume as shortening of fibres decrease
how do you calculate cardiac output?
HR x stroke volume
what affects stroke volume?
preload
after load - diastolic pressure, ventricules need overcome to pump blood AS in order to pump blood out ventricle pressure > artery pressure
contractility
what is contractility?
contractil capablity, strength of contraction of heart
How is contractility increased?
By sympatheric stimulatiion
chnages amount cyclic KMP in cell that influences Ca2+ to myofliments
How does contracte change ESPVR, end systolic pressure?
What happens to PV loops during exercise?
affects stroke volume and end-systolic pressure
by 1). increased end diastolic volume - by an increase venous return
2) .increase contractility - sympatheric increase as more Ca2+ to myofilmants, decreased end systolic volume
3) . increases artial pressure - increase afterload and lessens to reduction of end-systolic volume.
What affect does high HR have?
V high rate, impenge on filling time and decreased end-diasltic volume i.e how much is filled in diastole
What affect will hardening of aortic valve have on PV loop?
reduced blood flow in artery and increase afterload, as has larger diastolic pressure to over come
what affect does blood loss have on PV loop?
what affect does increase exercise have on PV loop
