5.3 - Structural heart diseases 2/2 Flashcards
Define structural heart disease?
- structural heart disease covers a number of defects which affect the valves and chambers of the heart and the aorta
- some defects are present at birth (congenital) while others form later in life (due to damage by infections etc)
What are some examples of congenital heart defects? (6)
- atrial septal defect (ASD)
- ventricular septal defect (VSD)
- coarctation of aorta
- patent foramen ovale (PFO)
- patent ductus arteriosus (PDA)
- teratology of fallot (TOF)
What are some examples of heart defects that develop later in life? (2)
- valvular dysfunctions (aortic stenosis, aortic regurgitation)
- muscular dysfunctions (cardiomyopathies)
What is an atrial septal defect (ASD)?
Hole in wall between the two atria
What is a ventricular septal defect (VSD)?
- wall between the two ventricles fails to develop in foetus –> hole in wall
- leads to mixing of oxygenated blood from LV with deoxygenated blood in RV
- child - poor weight gain, poor feeding, palpitations
What happens in tetralogy of fallot (TOF)?
- ventricular septal defect - hole in wall between ventricles
- pulmonary stenosis - pulmonary trunk is stenosed/narrowed
- overriding aorta - aorta sits above VSD hole so it sits above both LV and RV and allows for mixing of blood between them and into aorta
- right ventricular hypertrophy - thickening of RV
What is coarctation of the aorta?
- narrowing of aorta
- blood has to force its way through, so ventricle has to work harder to push more blood through narrowing
- leads to thickening of ventricles or heart failure
- serious condition, urgent repair needed
What is stenosis of aortic/mitral valve?
Narrowing of the valve
What is regurgitation of aortic/mitral valve?
Incompetence of valve (flappy, not tightly closed)
What is the epidemiology of aortic and mitral valve disease like?
- age 60+ = all types of valve disease become very prevalent
- mitral > aortic prevalence
- (mild) mitral regurgitation is the most common form of valve disease
- MR > AS > MS > AR
What is aortic stenosis?
When the aortic valve narrows and does not open fully, reducing or blocking blood flow into the aorta
What are some epidemiological facts about aortic stenosis?
- most common valvular disease in the US and Europe requiring treatment
- second most frequent cause for cardiac surgery
What is aortic stenosis preceded by?
Aortic sclerosis - aortic valve thickening without flow limitation (asymptomatic)
How is aortic stenosis suspected?
Often suspected by the presence of an early-peaking systolic ejection murmur and confirmed by echocardiography (heart walls are thickened)
What age does aortic stenosis most likely happen in?
It is largely a disease of older people >70 years
What are the risk factors of aortic stenosis? (8)
- hypertension
- high LDL
- smoking
- elevated C-reactive protein
- congenital bicuspid valves (aortic valve has 2 cusps, not 3)
- chronic kidney disease
- radiotherapy
- older age
What are the causes of aortic stenosis? (3)
- rheumatic heart disease
- congenital heart diseases
- calcium build up
What events trigger the pathophysiology of aortic stenosis?
- degeneration (age-related) or congenital bicuspid valve –> wear and tear of valve / disruption of valve endothelium
- untreated Group A Streptococcus URTI –> anti-Strep antibodies wrongly attack valves leading to inflammation of valve endocardium
- both these lead to fibrosis and calcification of aortic valve
What is the pathophysiology of aortic stenosis?
Triggers pathophysiology:
- degeneration (age-related) or congenital bicuspid valve –> wear and tear of valve / disruption of valve endothelium
- untreated Group A Streptococcus URTI –> anti-Strep antibodies wrongly attack valves leading to inflammation of valve endocardium
- both these lead to fibrosis and calcification of aortic valve
- fibrosis and calcification of aortic valve
- disrupted blood flow through aortic valve
- LV has to contract harder to pump blood through the stenotic valve
- over time, continuous forceful contraction of LV causes concentric LV myocardial hypertrophy
- hypertrophic LV becomes stiff overtime and harder to fill (increased muscle reduces volume) –> decreased cardiac output (diastolic dysfunction)
- pressure overload in LV backs up in the LA, causing it to dilate and ultimately leading to increase in pressure in lungs causing pulmonary congestion
What kind of hypertrophy is seen in aortic stenosis?
Concentric hypertrophy (increased thickness, reduces volume of LV) - remember that due to the narrowed valve, the LV contracts with more FORCE to allow all blood through (rather than there being a buildup of blood in LV)
In aortic stenosis, what clinical finding is associated with disrupted blood flow through the valve?
- turbulent blood flow through valve during systole on auscultation
- ejection systolic murmur (crescendo-decrescendo)
In aortic stenosis, what clinical finding is associated with LV contracting harder to get blood from aorta –> body?
Syncope on exertion - during exercise, decreased output to brain
In aortic stenosis, what clinical finding is associated with hypertrophied muscle (high oxygen demand) and increase in pressure in ventricles (resulting in less coronary perfusion)?
Angina on exertion
In aortic stenosis, what clinical finding is associated with increase back pressure in lungs –> pulmonary congestion?
- diffuse crackles on auscultation of lungs
- dyspnoea
What clinical findings are found in aortic stenosis? (5)
- turbulent blood flow through valve during systole on auscultation –> ejection systolic murmur (crescendo-decrescendo)
- syncope on exertion
- angina on exertion
- diffuse crackles on auscultation of lungs
- dyspnoea
How do patients with aortic stenosis present? (5)
- exertional dyspnoea and fatigue
- chest pain, angina
- syncope
- heart failure
- ejection systolic murmur
What do patients with aortic stenosis usually have a history of? (5)
- rheumatic fever
- high lipoprotein
- high LDL
- chronic kidney disease
- age >65
What investigations are done in aortic stenosis?
Doppler echo is essential to the diagnosis (for the pressure gradient)
How is aortic stenosis managed?
Aortic valve replacement (AVR)
How is severe aortic stenosis treated?
- transcatheter valve replacement
- surgical valve prosthesis
What should be taken into account when deciding treatment for aortic stenosis?
- lifetime risks and benefits associated with the type of approach:
- transcatheter vs surgical?
- type of valve - mechanical vs bioprosthetic?
What is aortic regurgitation?
Diastolic leakage of blood from the aorta into the left ventricle
What kind of murmur does aortic regurgitation cause?
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 happens if aortic regurgitation is acute?
Medical emergency - presenting with sudden onset of pulmonary oedema and hypotension or cardiogenic shock
What happens if aortic regurgitation is chronic?
Culminates into congestive heart failure
What is the epidemiology of aortic regurgitation like?
Not as common as aortic stenosis and mitral regurgitation
What are the congenital and acquired causes of aortic regurgitation? (5)
- rheumatic heart disease
- infective endocarditis
- aortic valve stenosis
- congenital heart defects
- congenital bicuspid valves
What are the causes of aortic regurgitation through aortic root dilation? (5)
- Marfan’s syndrome
- connective tissue disease/collagen vascular diseases
- idiopathic
- ankylosing spondylitis
- traumatic
What events trigger the pathophysiology of aortic regurgitation?
- Marfan’s syndrome, ankylosing spondylitis, syphilis, idiopathic –> aortic root dilation
- post inflammatory response (untreated group A streptococcus rheumatic fever, endocarditis); collagen vascular disease (i.e. good pasteurs disease); congenital bicuspid valve –> inflammation of valvular endocardium leading to abnormal valve leaflet
- aortic root dilation + inflammation of valvular endocardium leading to abnormal valve leaflet –> valve leaflets close poorly when aortic pressure is higher than LV during diastole
What is the pathophysiology of aortic regurgitation?
Triggers pathophysiology:
- Marfan’s syndrome, ankylosing spondylitis, syphilis, idiopathic –> aortic root dilation
- post inflammatory response (untreated group A streptococcus rheumatic fever, endocarditis); collagen vascular disease (i.e. good pasteurs disease); congenital bicuspid valve –> inflammation of valvular endocardium leading to abnormal valve leaflet
- aortic root dilation + inflammation of valvular endocardium leading to abnormal valve leaflet –> valve leaflets close poorly when aortic pressure is higher than LV during diastole
- valve leaflets close poorly when aortic pressure > LV pressure during diastole
- blood flow back from aorta to LV
- volume and pressure overload in LV = increase LV preload and afterload
- acutely, the dilation = increase in SV due to Frank Starling law
- chronically, LV dilates and eccentrically hypertrophies to accommodate increase in volume
- later excessive stretching weakens the myocardium and unable to contract properly leading to systolic heart failure (5 <–> 6)
- back pressure in LV to atria and ultimately lung vasculature leading to congestion
In aortic regurgitation, what clinical finding is associated with backflow from aorta to LV?
Diastolic murmur (between S2 and S1)
In aortic regurgitation, what clinical finding is associated with chronic dilation of LV –> early filling of heart during systole?
The S3 gallop sound that occurs in early diastole, produced by rapid filling and expansion of ventricles
In aortic regurgitation, what clinical finding is associated with hypertrophied muscle (high oxygen demand), reduced aortic pressure (compromised coronary circulation) and decrease in SV?
Angina on exertion, fatigue
In aortic regurgitation, what clinical finding is associated with back pressure in lungs –> pulmonary congestion?
- diffuse crackles on auscultation of lungs
- dyspnoea
- orthopnoea
What is a bounding/corrigan/collapsing pulse found in aortic regurgitation?
Results from large stroke volume followed by the exaggerated collapse of the large vessels on the diastolic return of blood to the LV (large upstroke and downstroke)
What clinical findings are associated with aortic regurgitation? (8)
- diastolic murmur
- S3 gallop in early diastole (rapid filling and expansion of ventricles)
- angina on exertion
- fatigue
- diffuse crackles on auscultation of lungs
- dyspnoea
- orthopnoea
- bounding/corrigan/collapsing pulse
How does acute aortic regurgitation present? (6)
- hypotension
- pulmonary oedema
- cardiogenic shock
- tachycardia
- cyanosis
- diastolic murmur
How does chronic aortic regurgitation present? (2)
- wide pulse pressure (high systolic BP, low diastolic BP - due to LV hypertrophy increasing systolic BP, and reduced blood in aorta reducing diastolic BP)
- corrigan pulse (water hammer pulse)
How do you investigate aortic regurgitation?
Echocardiography is the best non-invasive test to grade the severity of AR
What is the main way of managing acute aortic regurgitation?
Aortic valve replacement (AVR) - acute AR is a medical emergency
How do we manage asymptomatic patients with chronic severe aortic regurgitation?
Vasodilator therapy improves haemodynamics and delays the need for AVR