cardiac cycle.pdf

Cardiac Cycle

1. CARDIACCYCLE
Dr. Harish Kumar Singhal
Associate Professor
University College of Ayurved
Dr. S. R. Rajasthan Ayurved University, Jodhpur
Email:[email protected]
5/15/2021DR. HARISH KUMAR SINGHAL 1

2. CARDIACCYCLE
•One complete sequence of ventricular systole anddiastole
•Cycle of events that occurs as the heart contracts and relaxes
•Bothsidesofheart takesapproximately0.8secsataheart rate
of72beatsperminute
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3. CARDIACCYCLE
•Divided into seven phases (and duration of phases)
1.AtrialSystole(0.11s–0.53s)
2.IsovolumetricVentricular Contraction (0.05s)
3.Rapid Ventricular Ejection (0.22-0.27s)
4.Reduced Ventricular Ejection (0.22-0.27s)
5.IsovolumetricVentricularRelaxation(0.08s)
6.RapidVentricularFilling(0.11s)
7.ReducedVentricularFilling(0.19s)
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4. CARDIACCYCLE
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5. 1)ATRIALSYSTOLE
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-Mitral valve is already open
and blood passively flows
into the ventricle (from
previous cycle) approx80%
-During this phase,
contractionoftheatrium
tops up the ventricular
volume –remaining 20%
EDV-120ml
-Ventriclerelaxes

6. 1)ATRIALSYSTOLE
•-The "a" wave occurs
when the atrium
contracts, increasing
atrial pressure.
•-Blood arriving at the heart
flows back up the jugular
vein, causing the first wave in
the jugular venous pulse.
•-Ventricle pressure is not
raised
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7. 1)ATRIALSYSTOLE–ECG&HEARTSOUNDS
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-Preceded by p wave on ECG
-marks the depolarization of atria
-S4,heardinventricularhypertrophy
-Atriacontractsagainstastiffened ventricle

8. 2) ISOVOLUMETRIC VENTRICULAR
CONTRACTION
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-Left ventricles begins to
contract
-Increase in LVP
-Mitral valve closes
-Ventricular volume remains
the same (approximately
120ml)

9. 2)ISOVOLUMETRIC
CONTRACTION
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-
-LV pressure builds up
-LV volume remains
constant (both valves are
close) C wave –bulging
of mitral valve back to
atrium –slight increase
in pressure

10. 2) ISOVOLUMETRIC CONTRACTION –ECG
ANDHEART SOUNDS
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-QRS Complex
-Represents the ventricular depolarization
-1st heart sound –S1
-Closure of the mitral valve

11. 3) RAPID VENTRICULAR EJECTION
-Ventricular continues
contracting
-Pressure increased, greater
than the aortic pressure
(80mmhg)
-Opening of aortic valve
-Most of stroke volume
(almost 70ml) ejected
during this phase,
-Reduce LV volume
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12. 3) RAPID VENTRICULAR EJECTION
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-Increase in LVP
-Increase in Aortic
pressure due to
volume of blood
ejected
-Reduce in LV
Volume

13. 4) REDUCED VENTRICULAR EJECTION
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-Ventricular pressure
falls
-Aortic pressure falls
-Remaining of LV volume
still being ejected, due
to kinetic energy, with
reduced rate

14. 4) REDUCED VENTRICULAR EJECTION
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-Reduced both aortic and
ventricular pressure
-Reduced LV volume
-Slight increase in LA pressure
-T wave
-ventricles starts repolarizing

15. 5)ISOVOLUMETRIC VENTRICULAR
RELAXATION
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-Left ventricle relaxes
-Reduce pressure in LV
-Aortic valve closes
-LV volume constant –
End systolic Volume
(approximately 50ml)
-SV = EDV –ESV =70ml

16. 5)ISOVOLUMETRIC VENTRICULAR
RELAXATION
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Reduced LV Pressure
Incisura in aorta
LV Volume constant
LA pressure increases

17. 5)ISOVOLUMETRIC VENTRICULAR RELAXATION
–HEARTSOUND
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•S2 due to aortic valve closure
•Splitting of heart sounds –during inspiration –decrease in
intrathoracic pressure –increasein venous return to right side of
hard, increase in stroke volume, prolongs ejection time,delays
closure of pulmonary valve

18. 6) RAPID VENTRICULAR FILLING
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•LV relaxes
•LV pressure falls to its lowest
level and constant
•Mitral valve opens
•LV volume increases rapidly

19. 6) RAPID VENTRICULAR FILLING
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•LV pressure reduces and
remains the same(high
compliance)
•Aortic pressure
decreases
•LA pressure decreases
•LV volume increases

20. 6)RAPIDVENTRICULAR FILLING –HEART
SOUND
•S3 –normal in children but not adult
•Indicates volume overload as in CCF, mitral regurgitation
•Occurs due to passive, rapid ventricular filling
•No ECG deflection
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21. 7) REDUCED VENTRICULAR FILLING
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•Diastasis
•Longest phase in cardiac
cycle
•Final portion of ventricular
filling, slower rate
•LVvolumeincreases
•Increaseinheartratealtersthis
phase

23. THANKYOU
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