Cardiology 1 Flashcards
Define abdominal aortic aneurysm
A localised enlargement of the abdominal aorta such that the diameter is > 3 cm or > 50% larger than normal diameter.
o NOTE: normal diameter of the aorta = 2 cm
Explain the aetiology/risk factors for AAA
- There are NO specific identifiable causes
- Risk Factors
o Severe atherosclerotic damage to aortic wall
o Family history
o Smoking
o Male
o Age
o Hypertension
o Hyperlipidaemia
o Connective tissue disorders: Marfan’s syndrome, Ehlers-Danlos syndrome
o Inflammatory disorders: Behcet’s disease, Takayasu’s arteritis
Recognise the presenting symptoms of AAA
- Unruptured
o NO SYMPTOMS
o Usually an incidental finding
o May have pain in the back, abdomen, loin or groin
- RUPTURED
o Pain in the abdomen, back or loin
o Pain may be sudden or severe
o Syncope
o Shock
- NOTE: degree of shock depends on site of rupture and whether it is contained
Recognise the signs of AAA on physical examination
- Pulsatile and laterally expansile mass on bimanual palpation of the abdominal aorta
- Abdominal bruit
- Retroperitoneal haemorrhage can cause Grey-Turner’s sign
Identify appropriate investigations for AAA
- Bloods
o FBC, clotting screen, renal function and liver function
o Cross-match if surgery is planned
- Scans
o Ultrasound - can detect aneurysm but CANNOT tell whether it is leaking or not
o CT with contrast - can show whether an aneurysm has ruptured
o MRI angiography
Define Aortic Dissection
- A condition where a tear in the aortic intima allows blood to surge into the aortic wall, causing a split between the inner and outer tunica media, creating a false lumen
- Classification of aortic dissection:
o Type A: ASCENDING aorta (MOST COMMON)
o Type B: DESCENDING aorta (distal to the left subclavian artery)
Explain the aetiology/risk factors of aortic dissection
- Aortic dissection is usually preceded by degenerative changes in the smooth muscle of the aortic media
- Common causes and risk factors:
o HYPERTENSION
o Aortic atherosclerosis
o Connective tissue disease (e.g. Marfan’s, Ehlers-Danlos, SLE)
o Congenital cardiac abnormalities (e.g. coarctation of the aorta)
o Aortitis
o Iatrogenic (e.g. during angioplasty/angiography)
o Trauma
o Crack cocaine
- NOTE: expansion of the false lumen can lead to obstruction of the subclavian, carotid, coeliac and renal arteries
o Hypoperfusion of the target organs of these major arteries can give rise to other symptoms (e.g. carotid artery –> collapse)
Summarise the epidemiology of aortic dissection
- Most common in males aged 40-60 yrs
Recognise the presenting symptoms of aortic dissection
- MAIN SYMPTOM: sudden central ‘tearing’ pain, it may radiate to the back in between the shoulder blades (it can mimic MI)
- Other symptoms caused by obstruction of branches of the aorta:
o Carotid artery –> hemiparesis, dysphasia, blackout
o Coronary artery –> chest pain (angina or MI)
o Subclavian artery –> ataxia, loss of consciousness
o Anterior spinal artery –> paraplegia
o Coeliac axis –> severe abdominal pain (due to ischaemic bowel)
o Renal artery –> anuria, renal failure
Recognise the signs of aortic dissection on physical examination
- Murmur on the back (below the left scapula), descending to the abdomen
- Hypertension
- Blood pressure difference between the two arms > 20 mm Hg
- Wide pulse pressure
- Hypotension may suggest tamponade
o Check for pulsus paradoxus = abnormally large decrease in systolic blood pressure and pulse wave amplitude during inspiration
o This may indicate:
- Tamponade
- Pericarditis
- Chronic sleep apnoea
- Obstructive lung disease
- Signs of Aortic Regurgitation
o High volume collapsing pulse
o Early diastolic murmur over aortic area - Unequal arm pulses
- There may be a palpable abdominal mass
Identify appropriate investigations for aortic dissection
- Bloods
o FBC
o X-match 10 units of blood
o U&E - check renal function
o Clotting screen
- CXR
o Widened mediastinum
- ECG
o Often NORMAL
o If the ostia of the right coronary artery is compromised you may get signs of:
- Left ventricular hypertrophy
- Inferior MI
- CT Thorax
o Shows false lumen
- Echocardiography
o Transoesophageal allows visualisation
- Cardiac catheterisation and aortography
Define aortic regurgitation
Reflux of blood from the aorta into the left ventricle during diastole. Also known as aortic insufficiency
Explain the aetiology and risk factors of aortic regurgitation
- Aortic valve leaflet abnormalities or damage
o Bicuspid aortic valve
o Infective endocarditis
o Rheumatic fever
o Trauma
- Aortic root/ascending aorta dilatation
o Systemic hypertension
o Aortic dissection
o Aortitis
o Arthritides (e.g. rheumatoid arthritis, seronegative arthritides)
o Connective tissue disease (e.g. Marfan’s, Ehlers-Danlos)
o Pseudoxanthoma elasticum
o Osteogenesis imperfecta
- Pathophysiology
o Reflux of blood into the left ventricle results in left ventricular dilatation
o This means increased end diastolic volume and increased stroke volume
o The combination of increased stroke volume and low end-diastolic AORTIC pressure may explain the high-volume collapsing pulse
Summarise the epidemiology of aortic regurgitation
- Chronic AR often begins in the late 50s
* It is most frequently seen in patients > 80 yrs
Recognise the presenting symptoms of aortic regurgitation
- Chronic AR
o Initially ASYMPTOMATIC
o Later on, the patient may develop symptoms of heart failure (e.g. exertional dyspnoea, orthopnoea, fatigue)
- Severe Acute AR
o Sudden cardiovascular collapse (left ventricle cannot adapt to the rapid increase in end-diastolic volume)
- Symptoms related to aetiology (e.g. chest or back pain caused by aortic dissection)
Recognise the signs of aortic regurgitation on examination
- Collapsing (water-hammer) pulse
- Wide pulse pressure
- Thrusting and heaving displaced apex beat
- Early diastolic murmur over the aortic valve region
o Heard better at the left sternal edge when the patient is sitting forward with the breath held at the top of expiration
- NOTE: an ejection systolic murmur may also be heard because of increased flow across the valve (due to increased stroke volume)
- Austin Flint mid-diastolic murmur
o Heard over the apex
o Caused by turbulent reflux hitting the anterior cusp of the mitral valve causing a physiological mitral stenosis
- Rare signs associated with aortic regurgitation:
o Quincke’s Sign - visible pulsation on nail bed
o de Musset’s Sign - head nodding in time with the pulse
o Becker’s Sign - visible pulsation of the pupils and retinal arteries
o Muller’s Sign - visible pulsation of the uvula
o Corrigan’s Sign - visible pulsation in the neck
o Traube’s Sign - pistol shot (loud systolic and diastolic sounds) heard on auscultation of the femoral arteries
o Duroziez’s Sign - systolic and diastolic bruit heard on partial compression of the femoral artery with the stethoscope
o Rosenbach’s Sign - systolic pulsations of the liver
o Gerhard’s Sign - systolic pulsations of the spleen
o Hill’s Sign - popliteal cuff systolic pressure exceeding brachial pressure by > 60 mm Hg
Identify appropriate investigations for aortic regurgitation
- CXR
o Cardiomegaly
o Dilatation of ascending aorta
o Signs of pulmonary oedema (if accompanied by left heart failure)
- ECG
o May show left ventricular hypertrophy
- Deep S in V1/2
- Tall R in V5/6
- Inverted T waves in lead I, aVL, V5/6
- Left axis deviation
- Echocardiogram
o May show underlying cause (e.g. aortic root dilatation, bicuspid aortic valve)
o May show the effects of aortic regurgitation (e.g. left ventricular dilatation, fluttering of the anterior mitral valve leaflet)
o Doppler echocardiogram can show AR and indicate severity
o Repeat echos allow monitoring of progression (LV size and function)
- Cardiac catheterisation with angiography
o If there is any uncertainty about the functional state of the ventricle or the presence of coronary artery disease
Define aortic stenosis
Narrowing of the left ventricular outflow at the level of the aortic valve
Explain the aetiology and risk factors of aortic stenosis
- Stenosis can be secondary to rheumatic heart disease (MOST COMMON WORLDWIDE)
- Calcification of a congenital bicuspid aortic valve
- Calcification/degeneration of a tricuspid aortic valve in the elderly
Summarise the epidemiology of aortic stenosis
- Present in 3% of 75 yr olds
- More common in males
- Those with bicuspid aortic valve present earlier
Recognise the presenting symptoms of aortic stenosis
- May be ASYMPTOMATIC initially
- Angina (due to increased oxygen demand of the hypertrophied left ventricle)
- Syncope or dizziness on exercise (due to outflow obstruction)
- Symptoms of heart failure (e.g. dyspnoea, orthopnoea)
Recognise the signs of aortic stenosis on examination
- Narrow pulse pressure
- Slow-rising pulse
- Thrill in the aortic area (only if severe)
- Forceful sustained thrusting undisplaced apex beat
- Ejection systolic murmur at the aortic area, radiating to the carotid artery
- Second heart sound may be softened or absent (due to calcification)
- A bicuspid valve may produce an ejection click
Identify appropriate investigations for aortic stenosis
- ECG
o Signs of left ventricular hypertrophy
- Deep S in V1/2
- Tall R in V5/6
- Inverted T waves in I, aVL and V5/6
- Left axis deviation
o LBBB
- CXR
o Post-stenotic enlargement of ascending aorta
o Calcification of aortic valve
- Echocardiogram
o Visualises structural changes of the valves and level of stenosis (valvar, supravalvar or subvalvar)
o Estimation of aortic valve area and pressure gradient across the valve in systole
o Assess left ventricular function
- Cardiac angiography
o Allows differentiation from other causes of angina (e.g. MI)
o Allows assessment of concomitant coronary artery disease
- NOTE: 50% of patients with severe aortic stenosis have significant coronary artery disease
Define arterial ulcer
A localised area of damage and breakdown of skin due to inadequate arterial blood supply. Usually seen on the feet of patients with severe atheromatous narrowing of the arteries supplying the legs.
