Cardiology Flashcards
Define atrial fibrillation
AF is a supraventricular tachyarrhythmia characterised by uncoordinated atrial activity on the surface ECG. AF has an irregularly irregular rhythm.
Describe the aetiology of atrial fibrillation
May be no identifiable cause
Systemic: Advancing age Infection/sepsis Diabetes Hyperthyroidism (thyrotoxicosis) Hypertension Alcohol Electrolyte imbalance Pneumonia
Heart: Ischaemic heart disease e.g. MI, Coronary Artery Disease Congestive heart failure Hypertensive heart disease Heart failure Valvular heart disease Cardiomyopathies Pericarditis Myocarditis Rheumatic heart disease Sick sinus syndrome Atrial myxoma
Lung:
Bronchial carcinoma
Pulmonary embolism
Pneumonia
Summarise the epidemiology of atrial fibrillation
VERY COMMON in the elderly
Present in 5% of those > 65 years
May be paroxysmal
Affects men more than women
What are the presenting symptoms of atrial fibrillation?
Asymptomatic Palpitations Dizziness Syncope SOB Chest pain Fatigue Symptoms of the cause of AF
What are the signs on physical examination of atrial fibrillation?
Irregularly irregular pulse
Hypotension
Tachycardia
Difference in apical beat and radial pulse
Check for signs of thyroid disease and valvular disease
What are the appropriate investigations for atrial fibrillation?
12 lead ECG - shows irregularly irregular tachycardia (QRS complexes), absent P waves
Echocardiogram - determine if any valvular disease, pericardial disease, cardiomyopathies
Bloods:
Cardiac enzymes
TFT - test for hyperthyroidism as the cause (low TSH)
Lipid profile
U&Es, Mg2+ and Ca2+ (there is increased risk of digoxin toxicity with hypokalaemia, hypomagnesaemia and hypercalcaemia)
Serum transaminases - may be deranged if AF due to alcohol
What is the management of atrial fibrillation?
First and foremost, try to treat any reversible causes (e.g. thyrotoxicosis, chest infection)
If HAEMODYNAMICALLY UNSTABLE - DC CARDIOVERSION
- RHYTHM CONTROL
If > 48 hrs since onset of AF
Anticoagulate for 3-4 weeks before attempting cardioversion
If < 48 hrs since onset of AF:
DC cardioversion (2 x 100 J, 1 x 200 J)
Chemical cardioversion: flecainide or amiodarone
NOTE: flecainide is contraindicated if there is a history of ischaemic heart disease
Prophylaxis against AF: Sotalol Amiodarone Flecainide Consider pill-in-the-pocket (single dose of a cardioverting drug for patients with paroxysmal AF) strategy for suitable patients
RATE CONTROL in chronic (Permanent) AF Control ventricular rate with: Digoxin Verapamil (rate-limiting CCB) Beta-blockers
Aim for ventricular rate ~ 90 bpm
How is stroke risk stratified in atrial fibrillation?
CHA2DS2VASc Score
C - congestive heart failure (1) H - hypertension (1) A2 - age >75 (2) D - Diabetes Mellitus (1) S2 - previous stroke/TIA/thromboembolism (2) V - vascular disease (1) A - age 64-75 (1) Sc - female sex (1)
If low risk (score of 1) - OAC or aspirin
If high risk (score >2) - anticoagulation with warfarin or other oral anticoagulants eg DOACs
Define aortic regurgitation
The diastolic leakage of blood from the aorta into the left ventricle due to inadequate coaptation of valve leaflets resulting from either intrinsic valve disease or dilation of the aortic root.
Explain the aetiology of aortic regurgitation
- Primary disease of the aortic valve leaflets
- Rheumatic heart disease (developing countries)
- Congenital bicuspid aortic valve - Aortic root dilation
- Marfan’s syndrome or related connective tissue disease
- Aortitis secondary to syphilis, Behcet’s, Takayasu’s, reactive arthritis, or ankylosing spondylitis.
- Systemic hypertension
- Aortic dissection
- Arthritides (e.g. rheumatoid arthritis, seronegative arthritides)
- Pseudoxanthoma elasticum
- Osteogenesis imperfecta
Acute aortic regurgitation:
Aortic root dissection
Endocarditis can lead to rupture of leaflets or even paravalvular leaks.
Vegetations on the valvular cusps can also cause inadequate closure of leaflets, resulting in leakage of blood.
Summarise the epidemiology of aortic regurgitation
Less common than aortic stenosis and mitral regurgitation
Prevalence increases with age
More common in men than women
Chronic AR often begins in the late 50s
Most frequently seen in patients > 80 years
What are the presenting symptoms of aortic regurgitation?
Chronic AR: Initially ASYMPTOMATIC Later on, the patient may develop symptoms of heart failure: - Exertional dyspnoea - Orthopnoea - Fatigue - Paroxysmal nocturnal dyspnoea
Severe Acute AR:
Sudden cardiovascular collapse (LV can’t adapt to the rapid increase in end-diastolic volume). Symptoms related to aetiology (e.g. chest/back pain caused by aortic dissection).
Weakness
Chest pain
What are the signs on physical examination of aortic regurgitation?
End-diastolic murmur heard loudest on expiration, when sitting forwards and in the left sternal edge Collapsing pulse Pallor Rapid and faint peripheral pulse Tachypnoea Wide pulse pressure Thrusting and heaving displaced apex beat Basal lung crepitations
Rare signs:
Quincke’s Sign - visible pulsation on nail bed
de Musset’s Sign - head nodding in time with the pulse
Becker’s Sign - visible pulsation of the pupils and retinal arteries
Muller’s Sign - visible pulsation of the uvula
Corrigan’s Sign - visible pulsation in the neck
Traube’s Sign - pistol shot (loud systolic/diastolic sounds) heard at femoral arteries
Duroziez’s Sign - systolic and diastolic bruit heard on partial compression of the femoral artery with the stethoscope
Rosenbach’s Sign - systolic pulsations of the liver
Gerhard’s Sign - systolic pulsations of the spleen
Hill’s Sign - popliteal cuff systolic pressure exceeding brachial pressure by 60 mm Hg
What are the appropriate investigations for aortic regurgitation?
ECG - not diagnostic, may show non-specific ST-T wave changes, left axis deviation, or conduction abnormalities 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
CXR - may show cardiomegaly, dilatation of ascending aorta, signs of pulmonary oedema if heart failure also present
Echocardiogram - detection and evaluation of severity of AR. Visualisation of the origin of regurgitant jet and its width. May show underlying cause.
Cardiac catheterisation with angiography - If there is any uncertainty about the functional state of the ventricle or the presence of coronary artery disease
Define rheumatic fever
An autoimmune disease which can affect many systems including the heart, joints, brain and skin following group A streptococcal throat infection.
The effects on the heart can lead to permanent illness known as chronic rheumatic heart disease. Long-term penicillin secondary prophylaxis, acute rheumatic fever can recur causing cumulative damage to cardiac valvular tissue.
Explain the aetiology of rheumatic fever
Acute rheumatic fever is an autoimmune disease.
A group A streptococcal infection triggers an autoimmune response in a susceptible host. The response is targeted against cardiac, synovial, subcutaneous, epidermal and neuronal tissue.
What are the risk factors for rheumatic fever?
Poverty Overcrowded living quarters Family history of rheumatic fever D8/17 B cell antigen Indigenous populations
Summarise the epidemiology of rheumatic fever
Mainly in children aged 4-15 years old
Rare in people over 30 years old
94% of cases are in developing countries
No clear sex predilection, however chronic rheumatic heart disease is more common in females
More than 2.4 million children have rheumatic heart disease worldwide
What are the five hallmarks of rheumatic fever?
Carditis Arthritis Chorea Erythema marginatum Subutaneous nodules
What are the four minor manifestations of rheumatic fever?
Fever
Arthralgia
Elevated inflammatory markers
Prolonged PR interval on ECG
What are the presenting symptoms of rheumatic fever?
Fever
Joint pain (knees, ankles, wrists, elbows, and hips, usually asymmetrical)
Recent sore throat or scarlet fever (2-4 weeks previously)
Chest pain
SOB
Palpitations
Nodules on the skin
Restlessness, clumsiness, emotional lability and personality changes (indicates chorea)
What are the signs on physical examination of rheumatic fever?
Heart murmur - mitral regurgitation is the most common valvular problem caused which results in pan-systolic murmur heard loudest at apex and which radiates to the axilla OR aortic regurgitation causing an early diastolic murmur
Pericardial rub
Signs of congestive heart failure
Jerky, uncoordinated choreiform movements
Red, hot or swollen joints
Small, painless nodules beneath the skin
Erythema marginatum
What are the appropriate investigations for rheumatic fever?
Bloods:
ESR, CRP, WCC may be raised
Blood cultures - show no growth
ECG - prolonged PR interval
Chest X-Ray - may show congestive cardiac failure or chamber enlargement
Echocardiogram: may reveal morphological changes to the mitral and/or aortic valves. Allows you to see the severity of regurg.
Throat culture: growth of beta-haemolytic group A streptococci
Define abdominal aortic aneurysm
A permanent pathologial dilation of the aorta with a diameter >1.5 times the expected anteroposterior diameter of that segment, given the patient’s sex and body size.
Localised enlargement of the abdominal aorta such that the diameter is > 3 cm or > 50% larger than normal. Usually located BELOW the renal arteries.
(Normal abdominal aorta diameter = 2cm)
What are the risk factors for abdominal aortic aneurysm?
SMOKING Family history Increased age Male sex (however rupture more likely in females) Congenital/connective tissue disorders Dyslipidaemia COPD Atherosclerosis Hypetension Centripetal obesity
There are NO specific identifiable causes - may be due to atherosclerosis OR altered tissue metalloproteinases diminish the integrity of the arterial wall
Summarise the epidemiology of abdominal aortic aneurysms
Epidemiology varies by region, age and sex
Highest prevalence in male smokers
Prevalence increases with age
4-6 times more likely in men
What are the presenting symptoms of abdominal aortic aneurysm?
If unruptured: ASYMPTOMATIC and an incidental finding
If ruptured:
Abdominal, back, loin or groin pain which is sudden and severe
Syncope
Shock
What is the triad for the presentation of a ruptured abdominal aortic aneurysm?
Abdominal and/or back pain
Pulsatile abdominal mass
Hypotension
What are the signs on physical examination of abdominal aortic aneurysm?
Palpable, pulsatile, laterally expansile abdominal mass
Hypotension
Abdominal bruit
Retroperitoneal haemorrhage can cause Grey-Turner’s sign
What are the appropriate investigations for abdominal aortic aneurysm?
ABDOMINAL USS - abdominal aorta diameter >3cm. Cannot tell if aneurysm is leaking
Bloods:
ESR/CRP - if elevated, inflammatory AAA
FBC - leukocytosis and anaemia suggest inflectious AAA
Culture - if positive with leukocytosis and anaemia, suggests infectious AAA
CT angiography - shows if ruptured
MRI angiography - anatomical mapping to assist with operative planning
Define aortic dissection
A separation occurs in aortic wall intima, usually by a discrete intimal tear, causing blood flow into a new false channel composed of the inner and outer layers of the media.
Explain the aetiology of aortic dissection
Results from an intimal tear that expands into the media of the aortic wall which is preceded by degenerative changes in the smooth muscle of the media.
- HYPERTENSION
- Bleeding from the vasa vasorum
- Connective tissue disease: Marfan syndrome and Ehlers-Danlos syndrome (weakening of the media)
- Bicuspid aortic valve
- Aortic atherosclerosis
- Iatrogenic (aortic manipulation with cardiac surgery or interventional procedures.)
- Congenital cardiac abnormalities (e.g. coarctation of the aorta)
- Aortitis
- Trauma
How can aortic dissection give rise to organ hypoperfusion and associated symptoms?
Expansion of the false lumen can lead to obstruction of the subclavian, carotid, coeliac and renal arteries. Hypoperfusion of the target organs of these major arteries can give rise to other symptoms (e.g. carotid artery collapse).
What are the risk factors of aortic dissection?
Hypertension Atherosclerotic aneurysmal disease Marfan’s syndrome Ehlers-Danlos syndrome Bicuspid aortic valve Smoking Coarctation Crack cocaine use Family history of aortic dissection Increased age Heavy lifting Pregnancy
What is aortic coarctation?
Congenital abnormality whereby the aorta is narrowed
Summarise the epidemiology of aortic dissection
Mostly affects men over 50 years old (40-60 is most common)
0.5-3 cases per 100,000 people annually
What are the presenting symptoms of aortic dissection?
Acute severe central TEARING chest pain which radiates to back (interscapular and lower pain)
Other symptoms caused by obstruction of branches of the aorta:
Carotid artery - hemiparesis (weakness of half the body), dysphasia, blackout
Coronary artery - chest pain (angina or MI)
Subclavian artery - ataxia, loss of consciousness
Anterior spinal artery - paraplegia
Coeliac axis - severe abdominal pain (due to ischaemic bowel)
Renal artery - anuria, renal failure
What are the signs on physical examination of aortic dissection?
BLOOD PRESSURE DIFFERENCE BETWEEN THE TWO ARMS >20mmHg
Pulse deficit (reduced or absent due to aortic arch involvement)
Diastolic murmur on back below left scapula descending to abdomen (crescendo murmur common in proximal dissections)
Hypertension
Wide pulse pressure
Hypotension associated with tamponade
Signs of Aortic Regurgitation:
High volume collapsing pulse
Early diastolic murmur over aortic area
Pulsus paradoxus - Abnormally large decrease in systolic blood pressure and pulse wave amplitude during inspiration. May indicate: - Tamponade - Pericarditis - Chronic sleep apnoea - Obstructive lung disease
What are the appropriate investigations for aortic dissection?
CT ANGIOGRAPHY - will show intimal flap
ECG - often normal however if MI, ST segment depression
CXR - may show widened mediastinum
Bloods:
Cardiac enzymes - usually negative
Renal function tests - elevated creatinine and urea if renal perfusion is compromised
LFTs - elevated AST and ALT if liver perfusion is compromised
FBC - may show anaemia if haemorrhage
Type and cross to prepare for surgery
Define aortic stenosis
Obstruction of blood flow across the aortic valve due to pathological narrowing.
A progressive disease that presents after a long subclinical period with symptoms of decreased exercise capacity, exertional chest pain (angina), syncope, and heart failure.
Narrowing of the left ventricular outflow at the level of the aortic valve
Explain the aetiology of aortic stenosis
Calcification of aortic valve - most common cause in adults
Congenital bicuspid valve
Rheumatic heart disease in developing countries
What are the risk factors for aortic stenosis?
Smoking Hypertension Diabetes LDL cholesterol Age >60 years old Congenitally bicuspid valve Rheumatic heart disease Chronic kidney disease
