cardiac cycle Flashcards
what is stenosis ?
narrowing and increased resistance of valve?
what is regurg?
valve incomplete closure
what initiates the cardiac cycle?
AP from sa node
what constitutes cardiac cycle?
period of diastole and period of systole –> relaxation and contraction
what are the sequence of events in cardiac cycle?
1- electrical ( depolarization ) –> visualized as ecg?
2- Mechanical –> coordinated muscle tension development
3- pressure development ( blood squeezed by contracting muscles)
4- Flow occurs when valves are open and pressure gradient drives blood flow
what are the phases the systole phase?
1- isovolumic contraction ( isometric )
2- Rapid ventricular ejection
3- reduced ventricular ejection –> this is after rapid js to get rid of some of the left blood in the ventricle after ejection
what are the phases of diastole phase?
1- isovulmic relaxation ( isometric ) after the reduced ventricular ejection
2- rapid venticular filling
3- reduced ventricular filling diastasis
4- atrial systole
when are the av valves opened?
during the filling phase, mid to late ventricle diastole
when the atrium pressure is higher than ventricle
when do the av valves close?
when the ventricle pressure is higher than atrium –> isovolumetric contraction
when do the SL valves open ?
when the ventricle pressure is higher than aorta or trunk more than 80
mid to late systole
when do the SL valves close
when ventricle pressure is less than aorta less than 80
isovolumetric relaxation
when is the first heart sound produced?
S1 lub is produced when the av valves closes
Isovolumetric contraction
when is the second heart sound produced?
s2 dub produced when SL valves closes
isovolumetric relaxations
whats the normal sound in relation to the phases ?
S1 —> SYSTOLE –> S2 —> DIASTOLE —> S1
when are the abnormal heart sound heard?
S4 is b4 the normal sounds
S4 - S1 - S2 -S4 - S1
SHH LUB DUB SHHH LUB DUB
S3 is heard after the normal sounds
S1-S2-S3-S1-S2-S3
LUB DUB SHH LUB DUB SHH
whats the anatomical location and asculation location of mitral valve
anatomical –> 4th left costal cartilage
ausculation —-> apex of the heart
whats the anatomical location and asculation location of tricuspid valve?
anatomical —> 4th left intercostal space
auscultation –> left sternal border
whats the anatomical location and asculation location of pulmonary valve
anatomical —> left third costal cartilage
auscultation –> left second intercostal space
whats the anatomical location and asculation location of aorta valve
anatomical —> right third intercostal space
auscultation —> right second intercostal space
what are the causes of aortic stenosis?
senile degeneration ;
congenital deformity
Rheumatic heart disease
what happens in aortic stenosis?
increased left ventricle pressure to overcome the resistance of the small opening of the valve –> LV hypertrophy
- Large systolic pressure gradient between LV and Aorta due to the struggle of opening of the valve
what are the consequences of aortic stenosis?
1- CHF
2- Angina due to increased work of the heart
3- syncope during exercise due to decreased Ejection fraction
what are the abnormal sounds of aortic stenosis
1- diminished S2 —> s2 is the closure of SL valve, since in stenosis its not open enough it will not produce a loud closing sound at the beginning of isovolumetric relaxation
2- ejection systolic murmur —-> CUZ THE VENTRICLE STRUGGLES TO EJECT BLOOD = PRODUCE SOUNDS at MID TO LATE SYSTOLE PHASE
what are the causes of mitral stenosis?
mainly acute rheumatic fever
what happens in mitral stenosis?
the blood struggles leave from the atrium to the ventricle- INCREASED PRESSURE GRADIENT BETWEEN LA and LV
- LA hypertrophy –> stretch of the atrium –> atrial fibrillation
-Pulmonary congestion and edema and hypertension because the blood will accumulate in left atrium and the pulmonary veins w za7ma , the right side wont be able to pump blood to the lungs cuz its filled —> increase work on the right side–> Congestive heart failure
- Decrease LV filling = decrease cardiac output and SV
what are the abnormal sounds of the heart in mitral stenosis?
1- opening snap following S2 – due to its being stiff so when opened it causes a sound
2- late Diastolic murmur – due to blood struggling to leave atrium to ventricles –> IN MID TO LATE FILLING ( REDUCED FILLING )
what are causes of aortic regurgitation?
- aortic leaflets ( rheumatic )
- dilation of aortic roots ( aneurysm )
what happens in aortic regurgitation?
- in isovolumetric relaxation the blood flows back from aorta back to the ventricle ( during diastole )
- it increases stroke volume according to frank starling mechanism
-ACUTE AR– > increase LV diastolic pressure so when left atrium tries to empty the blood in the LV it will not be able to empty all of its blood cuz the lv has some blood that came from the aortia –> increased LA pressure so blood stays in pulmonary veins –> pulmonary edema.
- Chronic AR –> LV dilation due to increased volume and pressure
- High systolic atrial pressure due to the increased sv ( according to frank starling ) and it reduces the DIASTOLIC PRESSURE OF AORTA CUZ THE BLOOD GOES BACK NOT MUCH PRESSURE NEEDED
-Widens pulse pressure because theres decrease in diastolic ( pp = sys - diastolic ) , remember blood goes back to ventricle so less stretch less diastole
- lead to heart failure
what are abnormal sounds in aortic regurg
- Early diastolic murmur — DUE TO BLOOD FLOWING BACK TO THE VENTRICLE DURING ISOVOLUMENTER RELAXATION WHICH IS THE BEGNING OF DIASTOLE
what are the causes of mitral regurg
structural abnormality due to ischemia or infections
what happens in mitral regurg ?
- blood flows back from the ventricle to the atrium
- Increases LA volume and pressure – because goes from ventricle to atrium –> ( acute MR ) Pulmonary edema and congestion and hypertension
- Reduced LV cardiac output because the blood doesnt leave to aorta but goes back to LA ——-> fatigue
- OVERLOADING LV during diastole because in addition to the blood coming from the pulmonary veins you have the blood coming back from the LV.
in chronic MR —> increases LA size and compliance and pulmonary venous pressure
what are the abnormal sounds in mitral regurg?
holosystolic murmur –> during the isovolumetric contraction you will hear the blood going back to the atrium.
