CARDIO Flashcards
Aortic Dissection - Definition
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, and creating a false lumen. Type A (70%) = ascending aorta, Type B (30%) = descending aorta (distal to L subclavian artery) As the dissection extends, branches of the aorta occlude sequentially, may obstruct subclavian, carotid, coeliac and renal arteries Aortic valve incompetence, inferior MI and cardiac arrest may develop if dissection moves proximally
Aortic Dissection - Aetiology
Degenerative changes in the smooth muscle of the aortic media are the predisposing event.
Common causes and predisposing factors are:
. hypertension;
. aortic atherosclerosis;
. connective tissue disease (e.g. SLE, Marfans, Ehlers–Danlos);
. congenital cardiac abnormalities (e.g. aortic coarctation);
. aortitis (e.g. Takayasus aortitis, tertiary syphilis);
. iatrogenic (e.g. during angiography or angioplasty);
. trauma;
. crack cocaine.
Aortic Dissection - Epidemiology
Most common in males between 40 and 60 years.
EXTRA NOTES:
Pulsus paradoxus = abnormally large decrease in systolic blood pressure and pulse wave amplitude during inspiration. The normal fall in pressure is <10mmHg
All patients with Type A thoracic dissection should be considered for surgery
Management = crossmatch 10 units blood, hypotensives, labetolol
Aortic Dissection - History
Sudden central ‘tearing’ pain, may radiate to the back (may mimic an MI).
Aortic dissection can lead to occlusion of the aorta and its branches:
- Carotid obstruction = hemiparesis, dysphasia, blackout.
- Coronary artery obstruction = chest pain (angina or MI).
- Subclavian obstruction = Ataxia, loss of consciousness.
- Anterior spinal artery = paraplegia.
- Coeliac obstruction = severe abdominal pain (ischaemic bowel).
- Renal artery obstruction: Anuria, renal failure.
Aortic Dissection - Exam
Murmur on the back below left scapula, descending to abdomen.
Blood pressure (BP): Hypertension (BP discrepancy between arms of >20 mmHg), wide pulse pressure.
If hypotensive may signify tamponade, check for pulsus paradoxus.
Aortic insufficiency: Collapsing pulse, early diastolic murmur over aortic area.
Unequal arm pulses.
There may be a palpable abdominal mass.
Aortic Dissection- Investigation
Bloods: FBC, cross-match 10 units of blood, U&E (renal function), clotting.
CXR: Widened mediastinum, localized bulge in the aortic arch.
ECG: Often normal. Signs of left ventricular hypertrophy or inferior MI if dissection com-
promises the ostia of the right coronary artery.
CT-thorax: False lumen of dissection can be visualized.
Echocardiography: Transoesophageal is highly specific (TOE). Cardiac catheterization and aortography.
Aortic Regurgitation - Definition & Epidemiology
Reflux of blood from aorta into left ventricle (LV) during diastole. (AR) also called aortic insufficiency.
EPIDEMIOLOGY
Chronic AR often begins in the late 50s, documented most frequently in >80y/o
Aortic Regurgitation- Aetiology
- Aortic valve leaflet abnormalities or damage: Bicuspid aortic valve, infective endocarditis, rheumatic fever, trauma.
- Aortic root/ascending aorta dilation: Systemic hypertension, aortic dissection, aortitis (e.g. syphilis, Takayasus arteritis), arthritides (rheumatoid arthritis, seronegative arthrit- ides), Marfans syndrome, pseudoxanthoma elasticum, Ehlers–Danlos syndrome, osteogenesis imperfecta.
- Reflux of blood into the LV during diastole results in left ventricular dilation and high end-diastolic volume and high Stroke V. The combination of high SV and low end-diastolic pressure in the aorta may explain the collapsing pulse and the wide pulse pressure. In acute AR, the LV cannot adapt to the rapid increase in end-diastolic volume caused by regurgitant blood.
Aortic Regurgitation - History
Chronic AR: initially asymptomatic. Later, symptoms of heart failure: exertional dyspnoea, orthopnoea, fatigue. Occasionally angina.
Severe acute AR: sudden cardiovascular collapse.
Symptoms related to the aetiology, e.g. chest or back pain in patients with aortic dissection.
Aortic Regurgitation - Exam
- Collapsing ‘water-hammer’ pulse and wide pulse pressure
- Thrusting and heaving (volume-loaded) displaced apex beat (hyperdyamic)
- Early diastolic murmur at lower left sternal edge, better heard with patient sitting forward + expiration
- Ejection systolic murmur is often heard because of increased flow across the valve
- Austin-Flint mid-diastolic murmur (severe AR) = over the apex, from turbulent reflux hitting anterior cusp of the mitral valve and causing a physiological mitral stenosis
- Rare signs associated with a hyperdynamic pulse:
- Quincke’s sign = visible pulsations on nail bed
- de Musset’s sign = head nodding in time with pulse
- Becker’s sign = visible pulsations of the pupils and retinal arteries
- Müller’s sign = visible pulsations of the uvula
- Corrigan’s sign = visible pulsations in the neck
- Traube’s sign = Pistol-shot (systolic and diastolic) sounds heard on auscultation of the femoral arteris
Duroziezs sign: A systolic and diastolic bruit heard on partial compression of femoral artery
with a stethoscope.
Rosenbachs sign: Systolic pulsations of the liver.
Gerhards sign: Systolic pulsations of the spleen.
Hills sign: Popliteal cuff systolic pressure exceeding brachial pressure by >60 mmHg.
Aortic Regurgitation - Investigation
CXR: Cardiomegaly. Dilation of the ascending aorta. Signs of pulmonary oedema may be seen with left heart failure.
ECG: May show signs of left ventricular hypertrophy (deep S wave in V1–2, tall R wave in V5–6, inverted T waves in I, aVL, V5–6 and left-axis deviation).
Echocardiogram: 2D echo and M-mode may indicate the underlying cause (e.g. aortic root dilation, bicuspid aortic valve) or the effects of AR (left ventricular dilation/dysfunction and fluttering of the anterior mitral valve leaflet).
Doppler echocardiography for detecting AR and assessing severity.
Cardiac catheterization with angiography: If there is uncertainty about the functional state of the ventricle or the presence of coronary artery disease.
Aortic Stenosis - Definition
Narrowing of the left ventricular outflow at the level of the aortic valve.
Aortic Stenosis - Aetiology
- Stenosis secondary to rheumatic heart disease (commonest worldwide);
- calcification of a congenital bicuspid aortic valve, William’s syndrome
- calcification/degeneration of a tricuspid aortic valve in the elderly, (senile calcification)
Aortic Stenosis - History
Classic triad = angina, syncope and heart failure!
May be asymptomatic initially.
Angina (because of high O2 demand of the hypertrophied ventricles).
Syncope or dizziness on exercise.
Symptoms of heart failure (e.g. dyspnoea).
Aortic Stenosis - Examination
- BP: Narrow pulse pressure.
- Pulse: Slow-rising.
- Palpation: Thrill in the aortic area (if severe). Forceful sustained thrusting undisplaced apex
beat. - Auscultation: Harsh ejection systolic murmur at aortic area, radiating to the carotid artery
and apex. - Second heart sound (A2 component) may be softened or absent (because of
calcification). A bicuspid valve may produce an ejection click. May be an S4 (occurs more often with bicuspid valves)
Distinguish from aortic sclerosis and hypertrophic obstructive cardiomyopathy
(HOCM)
Aortic Stenosis -Investigations
- ECG: Signs of LV hypertrophy (deep S wave in V1–2, tall R wave in V5–6, inverted T waves in I, aVL, V5–6 and left-axis deviation), LBBB, LA enlargement.
- CXR: Post-stenotic enlargement of the ascending aorta, calcification of aortic valve.
- Echocardiogram: Visualizes structural changes of the valves and level of stenosis (valvar, supravalvar or subvalvar). Estimation of aortic valve area and pressure gradient across the
valve in systole and left ventricular function may be assessed. (DIAGNOSTIC)
-Doppler echo = can estimate gradient across valves, severe stenosis if peak gradient ≥ 50mmHg and valve area <1cm2
- Cardiac angiography: Allows differentiation from other causes of angina, and to assess for
concomitant coronary artery disease (50% of patients with severe aortic stenosis have significant coronary artery disease).
Aortic Stenosis- Extra notes
Pulse pressure = difference between systolic and diastolic pressure
Aortic sclerosis = senile degeneration with no left ventricular outflow tract degeneration. The pulse character is normal, a thrill is not palpable and ejection systolic murmur radiates only faintly. S2 normal.
Signs of LVH = deep S wave in V1-2, tall R wave in V5-6, inverted T wave in I, aVL and V5-6, LAD
William’s syndrome = rare neurodevelopmental disorder characterized by a distinctive ‘elfin’ facial appearance, along with a low nasal bridge, unusually cheerful demeanour and ease with strangers, developmental delay coupled with language deficiencies, profound visuo-spatial impairments, supravalvular aortic stenosis and transient high calcium
Atrial Fibrillation - definition
Rapid, chaotic and ineffective atrial electrical conduction. Often subdivided into: ‘permanent’, ‘persistent’ (>7 days and responsive to cardioversion), and ‘paroxysmal’.
EPIDEMIOLOGY
Very common in the elderly, may be paroxysmal
Atrial Fibrillation- Aetiology
There may be no identifiable cause (‘lone’ atrial fibrillation (AF)).
Secondary causes lead to abnormal atrial electrical pathways that result in AF.
Systemic causes: Thyrotoxicosis, hypertension, pneumonia, alcohol.
Heart: Mitral valve disease, ischaemic heart disease, rheumatic heart disease, cardiomyopathy, pericarditis, sick sinus syndrome, atrial myxoma.
Lung: Bronchial carcinoma, pulmonary embolism.
Atrial Fibrillation- Symptoms
Often asymptomatic. Some patients experience palpitations or syncope. Symptoms of the cause of the AF.
Atrial Fibrillation- Examination
Irregularly irregular pulse, difference in apical beat and radial pulse.
Look for thyroid disease and valvular heart disease.
Atrial Fibrillation-Investigations
- ECG: Uneven baseline (fibrillations) with absent P waves, irregular QRS complexes. If there is a saw-tooth baseline, consider if there is atrial flutter.
- Blood: Cardiacenzymes, TFT, lipidprofile, U&E, Mg2, Ca2, (risk of digoxin toxicity high with hypokalaemia, hypomagnesaemia or hypercalcaemia).
- Echocardiogram: To assess for mitral valve disease, left atrial dilation, left ventricular dysfunction or structural abnormalities.
Atrial Fibrillation- Management
Treat any reversible cause (e.g. thyrotoxicosis, chest infection). Specific treatment strategy focuses on:
(1) Rhythm control:
If the AF is >48h from onset, anticoagulate (at least 3–4 weeks) before attempting cardioversion.
- DC cardioversion: Synchronized DC shock (2x 100 J, 1 x 200 J).
- Chemical cardioversion: Flecainide (contraindicated if there is history of ischaemic heart disease) or amiodarone.
- Prophylaxis against AF: Sotalol, amiodarone or flecainide. Also consider providing ‘pill-in-
the-pocket’ strategy for suitable patients.
(2) Rate control = Chronic ‘permanent’ AF: Ventricular rate control with digoxin, verapamil and/or b- blockers. Aim for rate of 90/min..
(3) Stroke risk stratification:
Low-risk patients can be managed with aspirin, and high-risk patients require anticoagulation with warfarin
Risk factors indicating high risk are previous thromboembolic event, age 75 years with hypertension, diabetes or vascular disease, and/or clinical evidence of valve disease, heart failure or impaired left ventricular function.
COMPLICATIONS Thromboembolism, increased with LA enlargement/ LV dysfunction. Heart failure (or worsens existing heart failure), Dilated cardiomyopathy, Angina.
PROGNOSIS
Chronic AF in a diseased heart does not usually return to sinus rhythm.
EXTRA
Atrial myxoma = benign tumour of the heart, found on interatrial septum (left more common than right)
Fleicanide = VG Na+ channel blocker, slowing the upstroke of the cardiac action potential
Amiodarone = K+ channel blocker (main), β-blocker, Ca2+/Na+ channel blocker
Verapamil = VG Ca2+ channel blocker
CHA2DS2VASC = Congestive heart failure, Hypertension (>140/90), Age≥75, Diabetes, Prior stroke/TIA/thromboembolism, vascular disease (PVD, MI), Age 64-75 years, Sex (female)
Cardioversion more likely if: AF recent, <65y/o, underlying cause has been successfully treated
Cardiac Arrest - definition
Acute cessation of cardiac function.