Valvular Heart Disease Flashcards
What are the four phases of the cardiac cycle?
- Ventricular filling (Diastole)
- Isovolumetric contraction (Systole)
- Ejection (Systole)
- Isovolumetric relaxation (Diastole)
Each phase has distinct physiological events that contribute to heart function.
What occurs during ventricular filling?
Passive filling of the atria from the vena cava and pulmonary veins into the left and right atria, flowing into ventricles; mitral and tricuspid valves open, semilunar valves closed
At the end of diastole, atrial contraction occurs, contributing to ventricular filling.
What happens during isovolumetric contraction?
Pressure builds in the ventricles, causing closure of the AV valves; all valves are closed and ventricular pressure rises without volume change.
This phase is critical for assessing cardiac contractility.
What happens during ejection?
SYSTOLE where ventricular pressure exceeds the aorta and this triggers the opening of the semi-lunar valves and blood passes through to the rest of the body, where the end systolic volume is created and can be used to determine ejection fraction. Eventually ventricular pressure is below arterial pressure, so the semilunar valves close, creating a rise in arterial pressure
What causes the diacrotic notch?
The closure of the semilunar valves, which indicates end of systole closure and successful prevention of backflow stream.
What triggers the ejection phase of the cardiac cycle?
Ventricular pressure exceeds aortic pressure, opening the semilunar valves and allowing blood to flow into the aorta.
This phase results in the creation of end-systolic volume.
What is the dicrotic notch?
A rise in arterial pressure created by the closure of the semilunar valves, indicating the end of systole.
It is an important feature in arterial pressure waveform analysis.
What is isovolumetric relaxation?
DIASTOLE where both sets of valves are now closed and ventricular pressure begins to reduce to below atrial pressure, which leads to opening of the atrioventricular valves and restarting of the cycle
What does the S1 heart sound indicate?
Closure of the atrioventricular valves during early systole.
It is one of the primary heart sounds used in auscultation.
What does the S2 heart sound indicate?
Closure of the semilunar valves during late systole, creating a dicrotic notch on a graph.
S2 is typically louder than S1 due to higher pressures on the left side of the heart.
What is a split S2 heart sound?
Occurs when the closure of the aortic and pulmonary valves is out of sync, often normal during inspiration.
Pathological causes can include conditions like pulmonary hypertension and right bundle branch block.
What is paradoxical split S2?
Delay in closure of the aortic valve, causing greater splitting during expiration and pulmonary valve to close first.
This can occur due t conditions affecting the aortic valve such as severe aortic stenosis, hypertrophic obstructive cardiomyopathy or left bundle branch block.
This can occur due to conditions such as severe aortic stenosis.
What is fixed split S2?
Fixed split S2 is where there is a delay in closure of the pulmonary valves with no effect from insipiration.
This can occur due to an atrial septal defect, where expiration causes presssure in the right atrium to decrease as normal but high pressure blood flows abnormally from the left to the right atria through the defect, which disrupts the pressure gradient and delays closure of the PV valve.
What are the features of the mitral valve?
Mitral valve is bicuspid, with the anterior leaflet longer than the posterior leaflet.
What is S3 heart sound?
S3 heart sound is a low pitched sound in the isovolumetric diastole phase after S2, indicating fast ventricular filling. It can indicate systolic heart failure, where the left ventircle is compliant due to dilation. This sound occurs with mitral and aortic regurgitation.
This can be normal finding in children, pregnant women and young athletes.
What is the S4 heart sound?
S4 heart sound occurs prior to S1 heart sound in the diastole ventricular filling phase due to reduced ventricualr compliance And slow filling, assoicated with left ventircular hypertrophy.
What are the atrioventricular valves?
Atrioventricular valves consist of
-> Tricuspid
-> Mitral which is bicuspid, between the left atrium and ventricle and anterior leaflet is longer than left.
They are attached by fibrous cords called the chordate tendinae to connect it to the valve cusps at the papillary muscles on the ventricles, which work simultaneously to promote valve closure. Papillary muscles contract during ventricular systole to prevent valve prolapse into atria.
What is the consequence of volume overload?
Volume overload of the heart chamber causes eccentric hypertrophy, where dilatation thins the chamber walls, resulting in S3 heart sound due to issue with systole causing backflow of blood.
What is the consequence of pressure overload?
Pressure overload of the heart chamber causes concentric hypertrophy to enlarge the myocardial cells hypertrophy to accomodate for increased force of contraction, resulting in S4 heart sounds due to issue with diastole filling.
Which valvular diseases cause pressure overload?
Aortic stenosis
Mitral stensois
Aortic regurgitation
What is acute rheumatic fever?
Acute rheumatic fever is an autoimmune condition that occurs 2-4 weeks following a Group A Strep with a throat infection such as streptococcus pyogenes. This has an M protein that is targeted by immune cells, however its similar structure to cardiomycin results in molecular mimicry and susceptibility to pericarditis, myocarditis, mitral regurgitation, heart failure and infective endocarditis.
Which valvular diseases cause volume overload?
mitral Regurgitation
Aortic regurgitation
What is the presentation of acute rheumatic fever?
Clinical presentation is with fever, abdominal pain and epistaxis
JONES
* Joint pain with asymmetrical poly arterial IgA
* Carditis, resulting in chest pain, dyspnoea and palpitations. Pericarditis may resolve in haemodynamic instability while the myocarditis may result in acute heart failure and arrythmia. Endocarditis commonly affects the mitral valve most, followed by the aortic valve and tricuspid valve, where regurgitation and heart failure occur.
* Nodules that are subcutaneous found on the extensor regions of the hands,s feet and knees lasting for 2 weeks, occurring after pericarditis
* Erythema marginatum, where a large red circle with a clear border forms on the centre of the chest. It begins
* Syndenham’s chorea: involuntary jerky movements due to inflammation of the caudate nucleus and putamen, involved in movement regulation
How is diagnosis of rheumatic fever made?
Evidence of recent streptococcal infection from swab or antibody test alongside fulfilling:
2 major criteria or
1 minor criteria with 2 major criteria