cardiac cycle

single cardiac cycle includes all of the events associated with one
heartbeat. Thus, a cardiac cycle consists of systole and diastole of the
atria plus systole and diastole of the ventricles.

1. THANK YOU

2. | PHASES AND THEIR DURATION

EVENTS DURING CARDIAC CYCLE

"PHYSIOLOGY

3. (The heart chambers function in a coordinated fashion. Their actions are
regulated so that atria contract, called atrial systole , while ventricles relax,
called ventricular diastole, then ventricles contract(ventricular systole) while
atria relax (atrial diastole) Then the atria and ventricles both relax for a brief
interval. This series of events constitutes a complete heartbeat or cardiac

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In other words, It is the performance of the human heart from the ending
of one heartbeat to the beginning of the next is cardiac cycle.

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5. DURATION OF EACH PHASE

i
Duration of Cardiac Cycle:- In
anormal person, a heartbeat

is 72 beats/minute. So, the
duration of one cardiac cycle
can be calculated as:

4

For 72 beats time is 60
seconds
For 1 beat time is 60/72=0.8
seconds

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6. | Events During Cardiac Cycle

1. ATRIAL CONTRACTION (7

Mitral valve and tricuspid valve - open

Aortic valve and pulmonary valve - closed

“30% passive filling (already filled)
120% active filling (in this phase)

Atrial pressure > ventricular pressure

Aortic pressure > ventricular pressure

Atrial pressure elevation wave - “a wave”

[Atrioventricular valve (AV valve) - Mitral and Tricuspid valves]

‘[Semilunar valves - Aortic and Pulmonary valves]

7. | 2. ISO VOLUMETRIC CONTRACTION

(Ventricles contracting as closed chamber

(There is no inflow or outflow of blood

(Mitral valve and tricuspid valve - closed

(Aortic valve and pulmonary valve - closed

( Aortic pressure > ventricular pressure

| Atrial pressure elevation wave - “c wave"

(Atrial pressure < ventricular pressure |

(and “v wave"

8. PHASE

Mitral valve and tricuspid valve - closed

Aortic valve and pulmonary valve - open

Atrial pressure < ventricular pressure

Aortic pressure < ventricular pressure

Atrial pressure elevation wave - “v wave"
continues

Atrium receives oxygenated Blood from
lungs

9. 4. SLOW VENTRICULAR EJECTION PHASE |

Mitral valve and tricuspid valve - closed
Aortic valve and pulmonary valve - open

Atrial pressure < ventricular pressure

Aortic pressure < ventricular pressure

10. 5. ISO VOLUMENTRIC RELAXATION

Mitral Valveand tricuspid valve = closed

Aortic valve and pulmonary valve= closed

Atrial pressure < ventricular pressure

Aortic pressure > ventricular pressure

Atrial pressure elevation wave - “v wave” continues
Ventricle started relaxing and pressure falls rapidly
Atrium is still accumulating blood from lungs

2N? Heart Sound :- 52

When Aortic valve and Pulmonary valve closes.

11. 6. RAPID PASSIVE VENTRICULAR FILLING

Mitral valve and tricuspid valve -Open

Aortic valve and pulmonary valve - closed

Atrial pressure > ventricular pressure

(Ventricles have left over blood from previous ejection A
called ESV(End Systolic Volume)

Blood from Atrium falls passively (Because no Atrial
contection) into Ventricle and fills about 80%

12. 7. SLOW PASSIVE VENTRICULAR FILLING

Mitral valve and tricuspid valve -Open
Aortic valve and pulmonary valve - closed
Atrial pressure > ventricular pressure

Aortic pressure > ventricular pressure

Atrial pressure elevation wave - "v wave" falling

Oxygenated blood coming from lungs directly falls into ventricle through
Atrium , which works as a conduit (passage).

Its passive filing as no Atrial contraction
Itis the longest phase of Diastole

‘Also known as DIASTASIS.

Now SA node fires and the atria contracts and the cycle continues

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14. KNOW YOUR
BLOOD PRESSURE
NUMBER

What systolic, Diastolic Blood Pressure Numbers Mean?

When you
is your systolic blood pressure. The second, or "bottom," one Is diastol

The diastolic reading, or the bottom number is the pressure in the arteries when the
heart rests between beats. This s the time when the heart fils with blood and gets

110; systolic pressure and 70: diastolic pressure

Blood Pressure Stages

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THANK YOU