1B structural heart disease Flashcards
What is end systolic volume?
The volume of blood that stays behind in left ventricle after systole
What is end diastolic volume?
Amount of blood ventricle contains just before contraction
Define structural heart disease
Number of defects which affect the valves and chambers of the heart and the aorta
Can be congenital (present at birth) or develop later in life
Give 6 examples of congenital heart defects
- Atrial septal defect (ASD)
- Ventricular septal defect (VSD)
- Tetralogy of Fallot (TOF)
- Coarctation of the aorta
- Patent foramen ovale (PFO)
- Patent ductus arteriosus (PDA)
What is ASD?
Atrial septal defect: hole in the wall between the 2 atria
What is VSD?
Ventricular septal defect: when the wall between the two ventricles fails to develop in foetus leading to hole in wall.
This leads to mixing of oxygenated blood from left ventricle with deoxygenated blood in right ventricle.
What may a child with VSD present with?
- Poor weight gain
- Poor feeding
- Palpitations
What are treatments for VSD?
- Sometimes hole is small enough that it closes as child grows older
- If hole is large, surgeon needs to do open heart surgery or cardiac catheterisation to manually close it with a badge
What is TOF?
Tetralogy of Fallot (4 things):
- Ventricular septal defect- hole in wall between ventricles
- Pulmonary stenosis- where pulmonary trunk is stenosed (narrowed down)
- Widening of aortic valve so that it sits in both left and right ventricle and allows for mixing of blood between them and into aorta
- Right ventricular hypertrophy- thickening of wall of right ventricle
What is the treatment of TOF?
Child needs multiple surgeries to fix all of this e.g. aorta takeover and VSD
What is coarctation of the aorta?
- Narrowing of aorta
- Blood has to force its way through the narrowing so ventricle has to work harder to push more blood through that narrowing
- Leads to thickening of ventricles or heart failure
- Serious condition and needs urgent repair
What are examples of structural heart disease that develop later in life?
- Valvular dysfunctions (atrial stenosis/regurgitation)
- Muscular dysfunctions (cardiomyopathies)
What is aortic stenosis?
Narrowing of aortic valve- same with mitral stenosis.
The valve doesn’t open fully, reducing or blocking blood flow into aorta.
What is aortic regurgitation?
Incompetence of aortic valve- same with mitral regurgitation.
It is the diastolic leakage of blood from the aorta into the left ventricle.
What is aortic stenosis preceded by?
Aortic sclerosis (aortic valve thickening without flow limitation so patients can’t tell they have it)
How is aortic stenosis suspected?
By presence of an early-peaking systolic ejection murmurs and confirmed by echocardiography (where you see heart walls and can see thickening)
At what age does aortic stenosis most likely happen?
Older people in 60s/70s
What are the risk factors of aortic stenosis?
- HTN
- high LDL
- Smoking
- Elevated CRP
- Congenital bicuspid valves
- CKD
- Radiotherapy
- Older age
What are the causes of aortic stenosis?
- Rheumatic heart disease- commonest cause in developing countries
- Congenital heart disease
- Calcium build up
Describe the pathophysiology of aortic stenosis
- Wear and tear of valve/disruption of valve (degen/congenital) or Ab attack valves –> inflammation (Group A Strep URTI)
- Fibrosis and calcification of aortic valve
- Disrupted blood flow through the aortic valve
- LV has to contract harder to pump blood through
- LVH
- LV becomes stiff and harder to fill –> decreased CO and diastolic function
- Pressure overload in LV backs up in LA causing dilation therefore increase in lung pressure –> pulmonary congestion
What happens in rheumatic heart disease?
It’s an autoimmune inflammatory reaction triggered by prior Streptococcus infection that targets the valvular endothelium, leading to inflammation and eventually calcification of valve
How do aortic stenosis patients present and why?
-
Ejection Systolic murmur (Crescendo-Decrescendo)
- Turbulent blood flow through valve during systole on auscultation
-
Syncope on exertion
- LV has to contract harder so contraction less efficient during exercise, decrease in output to brain
-
Angina on exertion
- Hypertrophied muscle-high oxygen demand
- Increase in pressure in ventricles as compared to aorta resulting in less coronary perfusion
-
Diffuse crackles on auscultation of lungs and dyspnoea
- Increase in back pressure in lungs –> pulmonary congestion
What do patients with aortic stenosis usually have a history of?
- Rheumatic fever
- High lipoprotein
- High LDL
- CKD
- Age >65
What investigations are usually done for aortic stenosis?
- Doppler echo is essential (for pressure gradient)
What is the primary treatment for symptomatic AS patients?
Aortic valve replacement (AVR)
- Transcatheter valve replacement
- Surgical valve prosthesis
When is AVR given to asymptomatic AS patients?
- severe AS with LVEF <50%
- severe AS with rapid progression
- an abnormal exercise test
- Elevated serum B-type natriuretic peptide (BNP) levels
What kind of murmur does aortic regurgitation create?
Early diastolic ejection murmur
Why does aortic regurgitation occur?
Due to incompetence of valve leaflets resulting from either intrinsic valve disease or dilation of the aortic root
What does AS cause if it’s acute/chronic?
Acute: medical emergency, sudden onset of pulmonary oedema and HTN or cardiogenic shock
Chronic: it culminates into congestive cardiac failure
What are the congenital and acquired causes for AR?
- Rheumatic heart disease
- Infective endocarditis
- Aortic valve stenosis
- Congenital heart defects
- Congenital bicuspid valves
What are the causes of AR through aortic root dilation?
- Marfan’s syndrome
- Connective tissue disease/collagen vascular diseases
- Idiopathic
- Ankylosing spondylitis
- Traumatic
Describe the pathology of acute AR
- Aortic root dilation (Marfan’s, AS, syphilis, idiopathic) or inflammation of valvular endocardium –> abnormal valve leaflet (post infl, collagen vascular disease, congenital bicuspid valve)
- Valve leaflets close poorly when aortic pressure > LV pressure during diastole
- Blood flows back from aorta to LV
- Volume and pressure overload in LV: increase LV preload and afterload
- Dilatation: increase in SV due to Frank Starling Law
Describe the pathology of chronic AR
- Aortic root dilation (Marfan’s, AS, syphilis, idiopathic) or inflammation of valvular endocardium –> abnormal valve leaflet (post infl, collagen vascular disease, congenital bicuspid valve)
- Valve leaflets close poorly when aortic pressure > LV pressure during diastole
- Blood flows back from aorta to LV
- Volume and pressure overload in LV: increase LV preload and afterload
- LV dilates and eccentrically hypertrophies to accommodate increase in volume (LVH
- Weakens myocardium so impaired contraction –> systolic heart failure
- Back pressure in LV to atria therefore lung vasculature –> congestion
What are the clinical findings of AR and why?
-
Diastolic murmur
- Blood flowing backwards through valve from aorta to LV
-
S3 gallop sound
- Occurs in early diastole produced by early and rapid filling and expansion of ventricles
-
Angina on exertion/ fatigue
- Hypertrophied muscle means high O2 demand
- Pressure in aorta decreases so coronary circulation is compromised
- Decrease in SV and less blood flow to body
-
Diffuse crackles on auscultation of lungs, Dyspnoea, Orthopnoea
- Back pressure in lungs leading to pulmonary congestion
What is the history and presentation of AR?
Acute:
- Cardiogenic shock
- Tachycardia
- Cyanosis
- Pulmonary oedema
- Diastolic murmur
Chronic:
- Wide pulse pressure
- Corrigan (wate hammer pulse)
What investigations are done for aortic regurgitation?
- Echocardiography is the best non-invasive test to diagnose and grade the severity of AR