Cardiology Flashcards
What are the risk factors for atherosclerosis?
- Age
- Smoking
- High serum cholesterol
- Obesity
- Diabetes
- Hypertension
- Family history
In which arteries would you be most likely to find atheromatous plaques?
In the peripheral and coronary arteries - LAD, circumflex, RCA
Describe in 5 steps the progression of atherosclerosis.
- Fatty streaks
- Intermediate lesions
- Fibrous plaque
- Plaque rupture
- Plaque erosion
What is the earliest lesion of atherosclerosis? What do they consist of?
- Fatty streaks (appear at a very early age <10 years)
- Consist of aggregations of lipid–laden macrophages and T lymphocytes within the tunica intima
What can lesions progress to? What does this contain?
- Intermediate lesion
- Composed of layers of :
- Foam cells
- Vascular smooth muscle cells
- T lymphocytes
What can intermediate lesions progress to? What do these contain?
- Fibrous plaques or advanced lesions
- Impedes blood flow
- Prone to rupture
- Covered by dense fibrous cap made of ECM proteins including collagen (strength) and elastin (flexibility) laid down by SMC that overlies lipid core and necrotic debris
- May be calcified
- Contains: smooth muscle cells, macrophages and foam cells and T lymphocytes
Describe the process of atherosclerosis.
- High levels of LDL in the blood. Some deposits in the tunica intima and become oxidised - this activates endothelial cells to attract leukocytes (ENDOTHELIAL CELL DYSFUNCTION)
- Monocytes etc. are attracted to the site of damage (endothelium) - move to tunica intima (become macrophages)
- Macrophages take up oxidised lipid to form foam cells (inflammatory response). These foam cells encourage plaque progression by serving as a source of pro inflammatory cytokines. They also promote the migration of smooth muscle cells from the tunica media to the tunica intima and smooth muscle cell proliferation - this causes heightened synthesis of collagen
- Foam cells die - release lipid contents
- Fibrous cap maintaining the plaque has to be maintained by resorption and redeposition. However, if the balance is shifted, e.g. in favour of inflammatory conditions we get a plaque rupture. This causes blood coagulation = thrombus = impedes blood flow (occludes vessel)
Describe the process of leukocyte recruitment after the endothelial cells have been activated
- Capture
- Rolling
- Slow rolling
- Adhesion
- Trans-migration
Which histological layer of the artery may be thinned by an atheromatous plaque?
The tunica media
What is the treatment for atherosclerosis?
Percutaneous coronary intervention (PCI)
What is the major limitation of PCI? How can restenosis be avoided following PCI?
- Restenosis
- Drug eluting stents: anti-proliferative and drugs that inhibit healing
What is the key principle behind the pathogenesis of atherosclerosis?
It is an inflammatory process
What are the functions of the mitral and aortic valves?
- Mitral valve = lets blood flow the left atrium to the left ventricle
- Aortic valve = opens when the left ventricle squeezes to pump out blood, and closes in between heart beats to keep blood from going backward into the heart
Describe aortic stenosis. How common is it?
- A disease where the aortic orifice (aortic opening) is restricted and so the LV can’t eject blood properly in systole = pressure overload
- It is the commonest valvular disease
Describe the aetiology of aortic stenosis.
- Congenital bicuspid aortic valve
- Rheumatic heart disease
- Senile calcification of the valve
Describe the pathophysiology of aortic stenosis.
Aortic orifice is restricted, e.g. by calcific deposits and so there is a pressure gradient between the LV and the aorta. LV function is initially maintained due to compensatory hypertrophy. Overtime this becomes exhausted = LV failure
Give 3 symptoms of aortic stenosis. What is the onset of symptoms associated with?
- SAD:
- Exertional syncope
- Angina
- Exertional dyspnoea
Onset of symptoms is associated with poor prognosis
Give 3 signs of aortic stenosis including the murmur type.
- Slow rising carotid pulse and decreased pulse amplitude
- Soft or absent heart sounds (S2) if severe
- Ejection systolic murmur: <> shape (crescendo-descrendo character)
What investigation might you do in someone who you suspect to have aortic stenosis? Which two measurements are obtained?
- Echocardiography - reduced aortic outflow, LVH
- Two measurements are obtained: left ventricular size and function + Doppler derived gradient and valve area
- CXR
- ECG
Describe the management for someone with aortic stenosis.
- Ensure good dental hygiene
- Consider IE prophylaxis
- AORTIC VALVE REPLACEMENT or TAVI (Transcatheter Aortic Valve Implantation)
Who should be offered an aortic valve replacement?
- Symptomatic patients with aortic stenosis
- Any patient with decreasing ejection fraction
- Any patient undergoing CABG (coronary artery bypass graft) with moderate/severe aortic stenosis
What is mitral regurgitation? What is it associated with?
- Backflow of blood from the LV to the LA during systole - LV volume overload
- Associated with ATRIAL FIBRILLATION
Describe the aetiology of mitral regurgitation.
- Papillary muscle rupture
- Mitral valve prolapse
- Rheumatic heart disease
- IE
- Marfan’s syndrome
What is the pathophysiology of mitral regurgitation?
LA enlargement and LVH to maintain BP. Progressive LV volume overload -> dilatation and progressive heart failure
Give 3 symptoms of mitral regurgitation.
PEF:
1. Palpitations
- Exertional dyspnoea
- Fatigue
Give 4 signs of mitral regurgitation including its murmur. In chronic mitral regurgitation, what does the intensity of the murmur correlate with?
- Pansystolic murmur radiating to left axilla (always there)
ADS:
- Atrial fibrillation
- Displaced, thrusting apex
- Soft 1st heart sound + a 3rd heart sound
In chronic MR, the intensity of the murmur correlates with disease severity
What investigations might you do in someone who you suspect to have mitral regurgitation? What may these show?
- ECG - may show LA enlargement, atrial fibrillation and LV hypertrophy
- CXR - LA enlargment
- Echocardiogram: estimates LA/LV size and function
Describe the management of mitral regurgitation.
- Rate control for AF, e.g. beta blockers
- Vasodilators, e.g. ACEI
- Anticoagulation for AF
- Diuretics for fluid overload
- IE prophylaxis
- If symptomatic = surgery
What is aortic regurgitation?
A regurgitant aortic valve means blood leaks back into the LV during diastole due to ineffective aortic cusps
What is the aetiology of aortic regurgitation?
- Bicuspid aortic valve (should be tricuspid)
- Rheumatic heart disease
- IE
- Marfan’s syndrome
Describe the pathophysiology of aortic regurgitation.
Pressure and volume overload. Compensatory mechanisms - LV dilatation, LVH. Progressive dilation leads to HF
Give 3 symptoms of aortic regurgitation.
PAD:
- Palpitations
- Angina
- Dyspnoea
Give 4 signs of aortic regurgitation.
- Wide pulse pressure
- Water hammer pulse
- Diastolic blowing murmur
- Austin flint murmur
What investigations might you do in someone who you suspect to have aortic regurgitation?
CXR and echocardiogram
Describe the management for someone with aortic regurgitation.
- IE prophylaxis
- Vasodilators e.g. ACEI
- Regular echocardiograms to monitor progression
- Surgery if symptomatic
What is mitral stenosis?
Obstruction to LV inflow that prevents proper filling during diastole
What is the aetiology of mitral stenosis?
- Rheumatic heart disease (most common)
- Congenital
- Calcification
Describe the pathophysiology of mitral stenosis.
- LA dilation -> pulmonary congestion (as coming in from the pulmonary vein, reduced emptying)
- Increased trans-mitral pressures -> LA enlargement and AF
- Pulmonary venous hypertension causes RHF symptoms
- Hemoptysis: due to rupture of bronchial vessels due to elevated pulmonary pressure
Give 3 symptoms of mitral stenosis.
- Dyspnoea
- Haemoptysis (due to pulmonary oedema)
- Palpitations (AF)
Give 5 signs of mitral valve stenosis. What is its murmur?
- ‘a’ wave in jugular venous pulsations (due to pulmonary hypertension and right ventricular hypertrophy)
- Malar flush - pink patches on cheeks due to vasoconstriction
- Low pitched diastolic murmur
- Loud S1
- Tapping apex beat
- Murmur = rumbling mid-diastolic murmur with opening snap
What investigations might you do in someone who you suspect to have mitral stenosis? What might they show?
- ECG - atrial fibrillation and LA enlargement
- CXR - LA enlargement and pulmonary congestion
- Echocardiogram - GOLD STANDARD. Assess mitral valve mobility, gradient and mitral valve area
Describe the management for mitral stenosis.
- If in AF rate control, e.g. beta blockers/CCBs
- Anticoagulation if AF
- BALLOON VALVULOPLASTY or valve replacement
- IE prophylaxis
Why does medication not work for mitral and aortic stenosis?
The problem is mechanical and so medical therapy does not prevent progression
Explain the shape of the action potential graph.
- 4 = resting potential (-90mV) = due to Na+/K+ ATPase (3 Na+ move out for 2K+ that move into cell) + Na+/K+ leak channels (100 K+ out for every K+ in, but Na+/K+ ATPase much more prominent)
- 0 = rapid depolarisation = threshold reached (-70mV), leads to sodium gated fast channels opening. Na+ enters cells + depolarises for +20mV
- 1 = partial repolarisation = K+ channels open + K+ leaves cell. Inflow of Na+ stops
- 2 = plateau = voltage-gated Ca2+ channels open. Ca2+ moves in + counters K channels. Lasts approx. 200ms. Entry of Ca2+ into cell results in contraction of myocyte. Contraction of cardiac muscle longer than skeletal due to calcium channels that cause plateau. Less duration in atria than ventricles
- 3 = repolarisation = K+ outflow and Ca2+ inflow stops until resting potential reached. Closure of Ca2+ channels, opening of more K+ channels
What is an ECG? Give a few examples of conditions that we can identify through ECGs.
- The representation of the electrical events of the cardiac cycle
- Conditions: arrhythmias, myocardial ischaemia and infarction, pericarditis, electrolyte disturbances
What are the main pacemakers of the heart? Which is the dominant pacemaker?
- SA node = dominant pacemaker (60-100 bpm)
- AV node = back-up pacemaker (40-60 bpm)
- Ventricular cells = back-up pacemaker (20-45 bpm)
Starting with the sinoatrial node, where does the electrical impulse travel?
SA node - AV node - Bundle of His - Bundle branches - Purkinje fibres
What do the P, QRS and T wave represent?
- P wave = atrial depolarisation (60-80ms)
- QRS complex = ventricular depolarisation (100-120ms)
- T wave = ventricular repolarisation (120-160ms)
What does the PR interval represent? Why is it a bit longer?
- Reflects conduction through the AV node
- Accounts for delay that allows time for atria to contract before ventricles contract
ECG: how long should the PR interval be?
120-200ms
ECG: what is the J point?
Where the QRS complex becomes the ST segment
ECG: what is the normal axis of the QRS complex?
-30° -> +90°
How many seconds do the following represent on ECG paper?
a) small squares
b) large squares
a) 0.04s
b) 0.2s
What do the ECG leads measure?
The difference in electrical potential between two points
How many electrodes does a 12 lead ECG have?
10 electrodes - six on the chest, four on the limbs
What are the typical ECG findings for a right axis deviation? What is a right axis deviation associated with?
- Lead III has the most positive deflection and lead I should be negative
- Right axis deviation is associated with right ventricular hypertrophy
What are the bipolar and unipolar leads?
- Bipolar leads: measure difference in electrical potential between two different points on the body
- Unipolar leads: measure difference in electrical potential between one point on the body and a virtual reference point with zero electrical potential, located in the centre of the heart
What are the 12 leads of the ECG?
- 3 standard limb leads
- 3 augmented limb leads
- 6 precordial leads
What should the cardiac axis look like in healthy individuals? What should the most positive deflection be in? Why? Where would you see the most negative deflection? Why?
- In healthy individuals, you would expect the cardiac axis to lie between -30°and +90º. The overall direction of electrical activity is therefore towards leads I, II and III. As a result, you see a positive deflection in all these leads, with lead II showing the most positive deflection as it is the most closely aligned to the overall direction of electrical spread
- You would expect to see the most negative deflection in aVR. This is due to aVR providing a viewpoint of the heart from the opposite direction
What does a positive deflection mean in an ECG? How about a negative deflection? What does the height of a deflection tell us?
- When the electrical activity within the heart travels towards a lead you get a positive deflection
- When the electrical activity within the heart travels away from a lead you get a negative deflection
- The height of the deflection represents the amount of electrical activity flowing in that direction (i.e. the higher the deflection, the greater the amount of electrical activity flowing towards the lead
What are the typical ECG findings for a right axis deviation? What is a right axis deviation associated with?
Lead III has the most positive deflection and lead I should be negative. Right axis deviation is associated with right ventricular hypertrophy
What does the cardiac axis tell us? What do we need to determine the cardiac axis? What is the pathway of electrical activity in the heart? What do a positive and negative deflection tell us?
- The cardiac axis gives us an idea of the overall direction of electrical activity
- To determine the cardiac axis, you need to look at leads I, II and III
- In healthy individuals, the electrical activity of the heart begins at the sinoatrial node then spreads to the atrioventricular (AV) node. It then spreads down the bundle of His and then Purkinje fibres to cause ventricular contraction
- Whenever the direction of electrical activity moves towards a lead, a positive deflection is produced
- Whenever the direction of electrical activity moves away from a lead a negative deflection is produced
What are the typical ECG findings for a left axis deviation? What is it associated with?
- Lead I has the most positive deflection
- Leads II and III are negative
- Left axis deviation is associated with heart conduction abnormalities
Which leads correspond to which view of the heart? What can we infer from these?
- LEARN:
- Inferior = II, III, aVF - RCA
- Lateral = I, aVL, aVR, V5, V6 - LCx
- Anterior = V3, V4 - LAD
- Septal = V1, V2 - proximal LAD
- Understanding which leads represent which anatomical territory of the heart allows you to localise pathology
- For example, if there is ST elevation in leads V3 and V4 it suggests an anterior myocardial infarction (MI). You can then combine this with some anatomical knowledge of the heart’s blood supply, to allow you to work out which artery is likely to be affected (e.g. left anterior descending artery).
How do we systematically approach interpreting ECGs?
– Rate
– Rhythm
– Axis
– P, PR, QRS, ST, QT, T
ECG: where would you place lead 1 (bipolar)?
From the right arm to the left arm with the positive electrode being at the left arm. At 0°
ECG: where would you place lead 2?
From the right arm to the left leg with the positive electrode being at the left leg. At 60°
ECG: where would you place lead 3?
From the left arm to the left leg with the positive electrode being at the left leg. At 120°
ECG: where would you place lead avF (unipolar)?
From halfway between the left arm and right arm to the left leg with the positive electrode being at the left leg. At 90°
ECG: where would you place lead avL?
From halfway between the right arm and left leg to the left arm with the positive electrode being at the left arm. At -30°
ECG: where would you place lead avR?
From halfway between the left arm and left leg to the right arm with the positive electrode being at the right arm. At -150°
What are the unipolar chest leads?
- V1 = R. of sternum 4th intercostal space
- V2 = L. of sternum 4th intercostal space
- V3 = Inbetween V2 + V4
- V4 = R. of sternum 5th intercostal space
- V5 = 5th intercostal space anterior axillary line
- V6 = 5th intercostal space midaxillary line
What are Chamberlain’s 10 rules of a normal ECG?
ECG RULES:
- Rule 1 = PR interval should be 120 to 200 milliseconds or 3 to 5 little squares
- Rule 2 = the width of the QRS complex should not exceed 110 ms, less than 3 little squares
- Rule 3 = the QRS complex should be dominantly upright in leads I and II
- RULE 4 = QRS and T waves tend to have the same general direction in the limb leads
- RULE 5 = all waves are negative in lead aVR
- RULE 6 = the R wave must grow from V1 to at least V4, the S wave must grow from V1 to at least V3 and disappear in V6
- RULE 7 = the ST segment should start isoelectric except in V1 and V2 where it may be elevated
- RULE 8 = the P waves should be upright in I, II, and V2 to V6
- RULE 9 = there should be no Q wave or only a small q less than 0.04 seconds in width in I, II, V2 to V6
- RULE 10 = the T wave must be upright in I, II, V2 to V6
What is a P wave like in leads I, II and aVR?
Always positive in leads I + II, always negative in aVR
What do P waves look like in right and left atrial enlargement? How about in atrial fibrosis, obesity and hyperkalaemia?
- Right atrial enlargement = tall, pointed P wave (P pulmonale)
- Left atrial enlargement = ‘M’ shaped P wave (P mitrale)
- Atrial fibrosis, obesity and hyperkalaemia = low amplitude
What can a short PR interval indicate?
WPW (Wolff-Parkinson-White syndrome)
What does a long PR interval (>200ms) indicate?
First degree heart block
How long should the QRS complex be? When do we get broad QRS complexes, small QRS complexes and tall QRS complexes?
- <110ms
- Broad QRS = ventricular conduction delay / bundle branch block
- Small QRS complexes = obese patient, pericardial effusion, infiltrative cardiac disease
- Tall QRS complexes = left ventricular hypertrophy, thin patient
In which leads would you expect the QRS complex to be upright in?
Leads I and II
In which lead are all waves negative?
aVR
In which leads should T waves and P waves be upright?
Leads 1, 2, V2 -> V6
What part of the ECG does the plateau phase of the cardiac action potential coincide with?
QT interval
What happens to the QT interval when HR increases?
The QT interval decreases
Give 3 signs of abnormal T waves.
- Symmetrical
- Tall and peaked (hyperkalaemia)
- Biphasic (ischaemia or hypokalaemia) or inverted (non-specific but can indicate ischaemia/infarction, hypertrophy, cardiomyopathy)
What is the U wave related to? What is their appearance? When are they more prominent?
- The U wave is related to afterdepolarisations which follow repolarisation
- U waves are small, round, symmetrical and positive in lead II
- More prominent in slower heart rates
How do we determine heart rate from an ECG in a regular rhythm? How about in an irregular rhythm?
- Rule of 300: count the number of ‘big boxes’ between each QRS complex and divide this into 300, e.g. 300/6 = 50bpm
- If a patient’s heart rhythm is irregular the first method of heart rate calculation doesn’t work (as the R-R interval differs significantly throughout the ECG). As a result, you need to apply a different method:
- Count the number of complexes on the rhythm strip (each rhythm strip is typically 10 seconds long)
- Multiply the number of complexes by 6 (giving you the average number of complexes in 1 minute)
What does the QRS axis represent? What do QRS axis abnormalities hint at?
- The QRS axis represents the overall direction of the heart’s electrical activity
- Abnormalities hint at ventricular enlargement and conduction blocks
What aspect of the heart is represented by leads 2, 3 and aVF?
The inferior aspect
What might ST elevation in leads 2, 3 and aVF suggest?
RCA blockage. These leads show the activity of the inferior aspect of the heart and the RCA supplies the inferior aspect of the heart with blood
What is ischaemic heart disease? What is it broken down into? Which condition has ischaemic heart disease as its main cause?
- Ischaemic heart disease (or coronary artery disease) is a condition where the coronary arteries are narrowed or blocked
- Broken down into stable angina and acute coronary syndrome
- Angina’s commonest cause is IHD. This is a symptom of O2 supply/demand mismatch to the heart experienced on exertion
What is IHD primarily caused by? What happens when a coronary artery is 70-80% sclerosed? Why?
- Primarily caused by atherosclerosis = lipid rich plaques in arterial wall. Inflammatory, progressive process
- When 70-80% sclerosed: exertional symptoms show: angina. Exertional symptoms only as there is increased oxygen demand on exertion: heart muscle cannot access required oxygen volume due to artery occlusion (due to the atherosclerosis), therefore there is a supply-demand mismatch. Pain occurs: angina
What are the modifiable and non-modifiable risk factors for IHD?
- Non modifiable:
- Family history
- Age
- Ethnicity (S. Asian)
- Modifiable:
- Smoking
- Poor nutrition
- Sedentary lifestyle
- Alcohol
- Stress
- HTN
- Obesity
- DM
Give 5 possible causes of angina.
- Narrowed coronary artery = impairment of blood flow, e.g. atherosclerosis
- Increased distal resistance = LV hypertrophy
- Reduced O2 carrying capacity, e.g. anaemia
- Coronary artery spasm
- Thrombosis
Briefly describe the pathophysiology of angina that results from atherosclerosis.
On exertion there is increased O2 demand. Coronary blood flow is obstructed by an atherosclerotic plaque -> myocardial ischaemia -> angina
Briefly describe the pathophysiology of angina that results from anaemia.
On exertion there is increased O2 demand. In someone with anaemia there is reduced O2 transport -> myocardial ischaemia -> angina
How do blood vessels try and compensate for increased myocardial demand during exercise?
When myocardial demand increases, e.g. during exercise, microvascular resistance drops and flow increases
Why are blood vessels unable to compensate for increased myocardial demand in someone with CV disease?
In CV disease, epicardial resistance is high meaning microvascular resistance has to fall at rest to supply myocardial demand at rest. When this person exercises, the microvascular resistance can’t drop anymore and flow can’t increase to meet metabolic demand = angina!
What is the typical presentation of someone with IHD? With angina, how do we classify it?
- Central, crushing retrosternal chest pain, radiating into the jaw and typically the left arm
- Shortness of breath
- Nausea
- Sweating
- Palpitation
- Angina:
1. Constricting discomfort in front of chest, neck, shoulders, jaws or arms
2. Precipitated by physical exertion
3. Relieved by rest/GTN spray ~5 mins - Normal examination
- All 3 features: typical angina, 2 features: atypical angina, 1/none: non-anginal pain
What are the investigations for IHD?
- ECG: resting and exercise (to induce ischaemia)
- Blood tests: HbA1c, FBC, cholesterol profile
- Biological markers: troponin, myoglobin etc.
- Gold standard angina = CT CORONARY ANGIOGRAPHY
How would you describe the chest pain in angina?
Crushing central chest pain. Heavy and tight. The patient will often make a fist shape to describe the pain
Give 5 symptoms of angina.
- Crushing central chest pain
- The pain is relieved with rest or using a GTN spray
- The pain is provoked by physical exertion
- The pain might radiate to the arms, neck or jaw
- Breathlessness
Describe the primary prevention of angina.
- Risk factor modification
- Low dose aspirin
Describe the secondary prevention of angina.
- Aspirin
- Atorvastatin
- ACEi
- PCI/CABG if extensive disease
How do we treat IHD?
BANS:
- Beta-blocker, e.g. propanolol
- Dual antiplatelet: aspirin and clopidogrel
- Nitrate: GTN spray (to abort attacks)
- Statin: simvastatin
What is the symptomatic reflief and long term relief for angina?
- Symptomatic relief = GTN spray
- Long term symptomatic relief = beta blocker or CCB
Describe the action of beta blockers.
Beta blockers are beta-1 specific. They antagonise sympathetic activation and so are negatively chronotropic and inotropic. Myocardial work is reduced and so is myocardial demand = symptom relief
Give 3 side effects of beta blockers.
- Bradycardia
- Tiredness
- Erectile dysfunction
When might beta blockers be contraindicated?
They might be contraindicated in someone with asthma or in someone who is bradycardic
Describe the action of nitrates.
Nitrates, e.g. GTN spray are venodilators. Venodilators -> reduced venous return -> reduced pre-load -> reduced myocardial work and myocardial demand
Describe the action of Ca2+ channel blockers.
Ca2+ blockers are arterodilators -> reduced BP -> reduced afterload -> reduced myocardial demand
How does aspirin work?
Aspirin irreversibly inhibits COX. You get reduced TXA2 synthesis and so platelet aggregation is reduced.
Caution: Gastric ulcers!
What are statins used for?
They reduce the amount of LDL in the blood
Give 2 advantages and 1 disadvantage of PCI.
- Less invasive than CABG
- Convenient and acceptable
- High risk of restenosis
Give 1 advantage and 2 disadvantages of CABG.
- Good prognosis after surgery (preferred in diabetics and those >65)
- Very invasive
- Long recovery time
Name 3 different types of angina.
- Stable angina (as we see in IHD) = predictable, happens on exertion
- Unstable angina (ACS, later) = unexpected, happens during rest + accelerated during sleep. NOT relieved by rest or GTN spray
- Prinzmetal’s angina = sudden, no clear triggers, results from spasms or dysfunctions in coronary artery
What are acute coronary syndromes (ACS)?
ACS encompasses a spectrum of acute cardiac conditions including unstable angina, NSTEMI and STEMI
What is the common cause of ACS?
Thrombus from an atherosclerotic plaque blocking a coronary artery
What are uncommon causes of ACS?
- Coronary vasospasm
- Drug abuse
- Coronary artery dissection
Describe unstable angina, NSTEMI and STEMI.
- Unstable angina (ischaemia)
- NSTEMI (partial occlusion → subendocardial infarction). Non-ST elevation
- STEMI (complete occlusion). ST elevation
Describe the differences between stable angina and unstable angina. Include the pathophysiology, ECG and troponin.
- Stable angina: stable atherosclerotic plaque, vessel unable to dilate enough to allow adequate blood flow to meet myocardial demand. Pain upon exertion. Demand ischaemia, no infarct. Normal ECG. Normal troponins
- Unstable angina: plaque ruptures and thrombus forms, causing partial occlusion of the vessel. Pain at rest or progresses rapidly over a short period of time. Supply ischaemia, no infarct. Normal, inverted T waves, or ST depression. Normal troponins
Describe the differences between NSTEMI and STEMI.
- NSTEMI: the plaque rupture and thrombus formation causes partial occlusion of the vessel that results in injury and infarct to the subendocardial myocardium. Subendocardial infarct. Normal, inverted T waves, or ST depression. Troponin elevated
- STEMI: complete occlusion of the blood vessel lumen, resulting in transmural injury and infarct to the myocardium, which is related by ECG changes and a rise in troponins. Transmural infarct. Hyperacute T waves or ST elevation. Troponin elevated. Acute changes = ST elevation or hyperacute T waves, hours/days = T wave inversion, pathological Q waves
Why do you see increased serum troponin in NSTEMI and STEMI?
The occluding thrombus causes necrosis of cells and so myocardial damage. Troponin is a sensitive marker for cardiac muscle injury and so is significantly raised in reflection to this
What is the presentation of people with ACS?
- Central, constricting chest pain radiating to jaw/arms
- Sweating
- SOB
- >20 minutes
- Unstable angina: pain not relieved by rest or GTN spray
- Silent MI: in diabetics
Give 3 signs of unstable angina.
- Cardiac chest pain at rest
- Cardiac chest pain with crescendo patterns; pain becomes more frequent and easier provoked
- No significant rise in troponin
Give 6 signs/symptoms of MI.
- Unremitting and usually severe central cardiac chest pain
- Pain occurs at rest
- Sweating
- Breathlessness
- Nausea/vomiting
- 1/3 occur in bed at night
What investigations would you do on someone you suspect to have ACS?
- ECG
- Blood tests; look at serum troponin
- Coronary angiography
- Cardiac monitoring for arrhythmias
A raised troponin is not specific for ACS. In what other conditions might you see a raised troponin?
- Gram negative sepsis
- Pulmonary embolism
- Myocarditis
- Heart failure
- Arrhythmias
Describe the initial management for ACS.
- Get into hospital ASAP - call 999
- If STEMI, paramedics should call PCI centre for transfer
- Aspirin 300mg
- Pain relief e.g. morphine
- Oxygen if hypoxic
- Nitrates
- Clopidogrel
Describe the management for stable angina.
- Pharmacological: GTN SPRAY (symptomatic relief). Then BETA-BLOCKERS OR CCB, switch, combine
- Interventional: PERCUTANEOUS CORONARY INTERVENTION (preferred) or CORONARY ARTERY BYPASS GRAFT
Describe the management for NSTEMI/unstable angina.
- GTN SPRAY (symptomatic relief) and BETA BLOCKERS, e.g. bisoprolol or CCB if beta-blockers are CONTRAINDICATED
- Use GRACE score to predict 6 month mortality + risk of further cardio events
- Fondaparinux
- Low risk: ticagrelor (P2Y12 receptor antagonist) and aspirin
- Med/high risk: angiography + PCI, prasugrel (P2Y12 receptor antagonist) and aspirin
Describe the management for STEMI.
- PCI within 120 mins
- Fibrinolysis (if PCI not possible in <120 mins), e.g. alteplase
- Clopidogrel or prasugrel and aspirin
- Ticagrelor and aspirin
Describe the immediate management for a myocardial infarction.
- Prehospital: ASPIRIN 300mg and GTN SPRAY
- HOSPITAL - IMMEDIATE MANAGEMENT:
M - Morphine
O - Oxygen
N - Nitrates (GTN)
A - Aspirin (300mg)
Describe the secondary prevention for ACS.
- ACEi
- Clopidogrel
- Aspirin + atorvastatin
- Beta blocker
What are some complications that can happen post MI?
- Death
- Rupture of heart septum/papillary muscles
- Oedema (heart failure)
- Arrhythmias and aneurysm
- Dressler’s syndrome
What is the function of P2Y12?
It amplifies platelet activation
Give 3 potential side effects of P2Y12 inhibitors.
- Bleeding
- Rash
- GI disturbances
What are the 5 classes of risk factors for IHD?
- Clinical risk factors (hypertension, lipids, diabetes)
- Lifestyle risk factors (smoking, diet, physical inactivity)
- Environmental risk factors (air pollution, chemicals)
- Demographic risk factors (age, sex, ethnicity, genetic)
- Psychosocial risk factors (behaviour pattern, depression/anxiety, work, social support)
What are the layers of the heart wall?
- Endocardium = innermost layer, lines the cavities and valves of the heart
- Myocardium = composed of cardiac muscle, responsible for the contractions of the heart
- Epicardium = outermost layer of the heart, formed by the visceral layer of the PERICARDIUM. It is composed of connective tissue and fat. The connective tissue secretes a small amount of lubricating fluid into the pericardial cavity
What are the two layers of pericardium? How much serous fluid is there between these layers? What is the function of this fluid?
- Visceral and parietal pericardium
- 50ml
- It acts as a lubricant and so allows smooth movement of the heart inside the pericardium
What lies within the pericardium?
Great vessels
The pericardial sac has a small reserve volume. What happens if this volume is exceeded? What is Tamponade physiology?
- If this volume is exceeded, the pressure is translated to the cardiac chambers
- Tamponade physiology: small amount of volume added to space has dramatic effects on filling but so does removal of a small amount
What is pericarditis?
Inflammation of the pericardium with/without effusion
What are the causes of pericarditis?
- Infectious:
- Viral: coxsackievirus
- Bacterial: mycobacterium tuberculosis
- Histoplasma spp. (most likely type found in immunocompromised)
- Non-infectious:
- Trauma (common) and iatrogenic
- Autoimmune: rheumatoid arthritis, Sjogren’s syndrome, SLE
- Secondary metastatic tumours
What is the pathophysiology of pericarditis?
- Inflammation of the pericardium (pericardial vascularisation, polymorphonuclear leukocyte infiltration)
- This leads to the narrowing of the pericardial space and scarring of the fibrous pericardium
- IF UNTREATED, we get a fibrinous reaction = a build up of exudate and adhesions in the pericardial space = PERICARDIAL EFFUSION
- Pericardial effusion puts pressure on the cardiac myocytes = cardiac dysfunction. The fluid may be serous or haemorrhagic
What are the symptoms of pericarditis?
• Severe chest pain
- Sharp, pleuritic, rapid onset
- Worse when laying flat + inspiration
- Relieved by sitting forward
- Radiates to trapezius ridge
- Dyspnoea
- Cough
- Hiccups
- Fever
- Myalgia
What are the signs of pericarditis?
- Pericardial rub friction rub on auscultation - high pitched scratchy sound heard loudest on the midline during inspiration
- Tachycardia
- Peripheral oedema
- Increased JVP
- PERICARDIAL EFFUSION:
- Bronchial breathing at left base
- Muffled heart sounds
What are the investigations for pericarditis? What would these show?
- ECG: DIAGNOSTIC
- Saddle-shaped ST elevation
- PR depression
- CXR:
• Effusion may cause cardiomegaly
- Serum troponin, CRP
How do we treat pericarditis?
- NSAIDS with gastric protection: ibuprofen for two weeks, aspirin for two weeks. Colchicine for three months to reduce recurrence risk
- Reduce physical activity until symptoms resolve
- Treat the cause
How do we treat pericardial effusion?
- Treat the cause
- Pericardiocentesis
What is a cardiac tamponade? What is the pathophysiology? What are the symptoms? What are the investigations? What is the treatement?
- Cardiac tamponade = life threatening condition whereby there is an accumulation of fluid in the pericardial space → compression of the heart chambers → decrease in venous return → decrease in filling in the heart → reducing cardiac output. Major COMPLICATION of pericarditis
- Beck’s triad: falling BP, rising JVP, and muffled heart sound. Also pulsus paradoxus (large decrease in stroke volume → systolic blood pressure drops by > 10mmHg on inspiration)
- Investigations: echocardiogram = gold standard
- Treatment = pericardiocentesis
What is the difference between pericardial effusion and pericardial tamponade?
- Pericardial effusion = happens when pericardial fluid builds up slowly over time, which allows the pericardium to stretch out to accommodate bigger and bigger volumes of fluid without compressing the heart. Over time, it can cause chest pain, shortness of breath, and compression of near structures. Ultimately, if the pressure inside the pericardial cavity increases enough to compress the heart muscle, it may lead to pericardial tamponade.
- Pericardial tamponade = when there’s a sudden fluid accumulation, the pericardium has no time to adjust, so even small amounts can cause a dramatic increase of pressure inside the pericardial sac, resulting in acute pericardial tamponade
What are the causes of pericardial tamponade?
- Chest trauma, e.g. stab wound or blunt trauma, rupture of the aorta, rupture of the ventricle after a heart attack, or as a complication of cardiac surgery
- It can also appear more gradually in individuals with pericardial infection, pericarditis or cancer, due to a progressive build-up of pericardial fluid over time
What are the signs of pericardial tamponade?
- Beck’s triad:
- Low blood pressure
- Distension of the jugular veins
- Muffled heart sounds
What investigations should be done for a pericardial tamponade?
- CXR - enlargement of the heart
- Echocardiogram - right-sided chamber collapse during diastole
- ECG - low voltage QRS complex
How do we manage pericardial tamponade?
Pericardiocentesis
You are a junior doctor and see a 26 year old woman who came to A&E complaining of chest pain. She has a past medical history of type 1 diabetes, and has a family history of rheumatoid arthritis. You decide to perform an ECG, and whilst you’re placing the leads you notice a widespread rash on the patient’s cheeks, neck and chest, which she says gets worse after she’s been in the sun.
The ECG shows widespread saddle-shaped ST elevation.
What is the likely cause of her chest pain?
a. STEMI
b. Infective Endocarditis
c. Prinzmetal Angina
d. Pericarditis
D. Pericarditis
You are a junior doctor and see a 26 year old woman who came to A&E complaining of chest pain. She has a past medical history of type 1 diabetes, and has a family history of rheumatoid arthritis. You decide to perform an ECG, and whilst you’re placing the leads you notice a widespread rash on the patient’s cheeks, neck and chest, which she says gets worse after she’s been in the sun.
The ECG shows widespread saddle-shaped ST elevation.
What is the most likely underlying cause?
a. Her Type 1 Diabetes Mellitus
b. Rheumatoid arthritis
c. Systemic Lupus Erythematosus
d. Mycobacterium Tuberculosis
C. Systemic Lupus Erythematosus (SLE)
What is the definition of heart failure? What happens in order for cardiac output to be maintained? What happens eventually?
- Inability of the heart to deliver blood and thus oxygen at a rate that is commensurate with the requirements of the body. Can result from STRUCTURAL/FUNCTIONAL cardiac disorder that impairs the heart’s ability to function
- Compensatory physiological changes occur in order to maintain cardiac output. They are eventually overwhelmed and become pathophysiological:
- [sympathetic system activation] BP falls → detected by baroreceptors → sympathetic activation → positively inotropic/chronotropic → CO increases
- RAAS system
What are the different types of heart failure?
- Acute heart failure = new onset acute or decompensation of chronic
- Chronic heart failure = develops/progresses slowly and arterial pressure is well maintained until late
- Systolic failure = inability of the ventricle to contract normally
- Diastolic failure = inability of the ventricle to relax and fill normally
- Left ventricular failure = either systolic or diastolic failure of the left ventricle
- Right ventricular failure = either systolic or diastolic failure of the right ventricle
What is the aetiology of left sided heart failure?
- Coronary artery disease
- Myocardial infarction
- Cardiomyopathy
- Valvular heart disease
- Arrhythmias
What is the aetiology of right sided heart failure?
- Right ventricular infarct
- Pulmonary hypertension
- Pulmonary embolism
- COPD
- Progression of left sided heart failure
- COR PULMONALE (disease of lung/pulmonary vessels → pulmonary hypertension → RV hypertrophy → RHF with venous overload, peripheral oedema, hepatic congestion)
What is the aetiology of systolic heart failure?
- ISCHAEMIC HEART DISEASE
- Myocardial infection
- Cardiomyopathy
What is the aetiology of diastolic heart failure?
- Aortic stenosis
- Chronic hypertension
What is the pathophysiology of heart failure?
- Myocardium fails, so there is a decreased volume of blood ejected. This causes an increase in preload
- An increase in ventricular load causes hypertrophy of the myocardium. An increase in the size and number of cells causes an increase in myocardial demand for oxygen. This causes the myocardium to become ischaemic = patchy fibrosis = stiffness and reduced contractibility
- Reduced contractibility = increased workload and amount of blood remaining. More force needed to maintain cardiac output = cells become tired = pathological
- Increased afterload and preload = increased cardiac work = damage to myocytes = decreased cardiac output = reduced blood flow to kidneys etc. = activates RAAS system and adrenergic pathway. This causes Na2+ and water retention, increased HR and contraction force, and cardiotoxicity
What are the symptoms of left sided heart failure? Why?
- 3 cardinal symptoms: SHORTNESS OF BREATH, FATIGUE, ANKLE SWELLING
- EXERTIONAL DYSPNOEA - this is because blood backs up to the lungs via pulmonary vein as not pumped around the body
- FATIGUE
- PAROXYSMAL NOCTURNAL DYSPNOEA
- Orthopnoea
- Poor exercise tolerance
- Nocturnal cough
- Wheeze
- Nocturia
- Cold peripheries
What are the symptoms of right sided heart failure? Why? What is the classifcation for heart failure
- Peripheral OEDEMA (ankle swelling) - this is because blood backs up to the body via the vena cava
- ASCITES
- RAISED JVP
- HEPATOMEGALY
- Nausea
- Facial engorgement
- Epistaxis
- Cyanosis
- NEW YORK CLASSIFICATION
- Hypotension
What are the symptoms and signs of heart failure?
- 3 cardinal symptoms: SHORTNESS OF BREATH, FATIGUE, ANKLE SWELLING
SOFA PC:
- Shortness of breath
- Orthopnoea
- Fatigue
- Ankle swelling
- Pulmonary oedema (due to backflow from decreased CO; produced cough with pink frothy sputum)
- Cold peripheries
- Raised JVP
- End respiratory crackles
What are the investigations for heart failure? What is the mnemonic for assessing heart failure through a chest X-ray?
- NT-pro BNP (BRAIN NATRIURETIC PEPTIDE) = a marker of heart failure, released when the myocardial walls are under stress
- ECG
- Transthoracic ECG: wall motion abnormalities, valvular disease, cardiomyopathies
- GOLD STANDARD = ECHOCARDIOGRAPHY
- Chest X-ray (ABCDE):
– Alveolar oedema (bat wing shadowing)
– Kerley B Lines
– Cardiomegaly
– Dilated upper lobe vessels of lungs
– Effusions (pleural)
What is the treatment for acute heart failure? What is the treatment for chronic heart failure? Why?
- Acute HF = OMFG: oxygen, morphine, furosemide, GTN spray
- Chronic HF:
- Lifestyle changes: stop smoking, low salt, weight and nutrition
- Medication:
- 1st line = ACEIs, e.g. ramipril and BETA BLOCKERS, e.g. bisoprolol
- 2nd line = ALDOSTERONE RECEPTOR ANTAGONISTS, e.g. spironolactone
- 3rd line = Digoxin
- Symptomatic relief: DIURETICS - excretion of water = reduces preload and BP. Loop diuretics (furosemide), thiazide diuretics (bendroflumethiazide), aldosterone antagonists (spironolactone)
What is Cor Pulmonale?
Right sided heart failure caused by chronic pulmonary arterial hypertension
What are the causes of Cor Pulmonale?
- Chronic lung disease, e.g. COPD
- Pulmonary vascular disorders
- Neuromuscular and skeletal diseases
What are the symptoms of Cor Pulmonale?
- Dyspnoea
- Fatigue
- Syncope
What are the signs of Cor Pulmonale?
- Cyanosis
- Tachycardia
- Raised JVP
- RV heave
- Pan-systolic murmur due to tricuspid regurgitation
- Hepatomegaly
- Oedema
What are the investigations for Cor Pulmonale?
- ABG – hypoxia +/- hypercapnia
What is the management for Cor Pulmonale?
- TREAT UNDERLYING CAUSE
- Give oxygen to treat respiratory failure
- Treat cardiac failure the same, e.g. diuretics
- Consider venesection if haematocrit >55
- Consider heart-lung transplantation in young patients
A patient with recently diagnosed heart failure comes to your GP practice for a check-up and medication review. He tells you that he has felt a little weaker and more tired than usual recently. His current medications include: Furosemide, Ramipril, Bisoprolol
His blood results show: Sodium: 142 (135-145) Potassium: 2.4 (3.5-5.5)
- Which of the following drugs is the most likely cause of the electrolyte abnormality?
a. Furosemide
b. Ramipril
c. Bisoprolol
d. None of the above
A. Furosemide
A patient with recently diagnosed heart failure comes to your GP practice for a check-up and medication review. He tells you that he has felt a little weaker and more tired than usual recently. His current medications include: Furosemide, Ramipril, Bisoprolol
His blood results show: Sodium: 142 (135-145) Potassium: 2.4 (3.5-5.5)
- Which of the following diuretics is the most appropriate for this patient?
a. Furosemide
b. Bendroflumethiazide
c. Spironolactone
d. Verapamil
C. Spironolactone
What is the Tetralogy of Fallot? What is it characterised by?
A congenital heart defect characterised by 4 defects:
- Ventricular septal defect (a hole allowing blood to flow between the two ventricles)
- Over-riding aorta (aorta expands to allow blood from both ventricles to enter)
- RV hypertrophy
- Pulmonary stenosis (narrowing of the exit of the right ventricle)
What is the physiology of Tetralogy of Fallot?
- The stenosis of the RV outflow leads to the RV being at a higher pressure than the left
- Therefore deoxygenated blood passes from the RV to the LV
Would a baby born with Tetralogy of Fallot be cyanotic?
YES! There is a greater pressure in the RV than the LV and so blood is shunted into the LV -> CYANOSIS!
What are the signs, investigations and treatment of Tetralogy of Fallot?
- Signs: cyanosis, harsh systolic ejection murmur, tachypnoea
- Investigations = pulse oximetry, echocardiogram, ECG, CXR
- Treatment = surgical repair
What is ventricular septal defect? Would a baby born with ventricular septal defect be cyanotic?
- An abnormal connection between the two ventricles
- No. There is a higher pressure in the LV than the RV and so blood is shunted from the left to right meaning there is an increased amount of blood going to the lungs; not cyanotic
What are the signs of a large VSD? How about a small VSD?
- Moderate-large show exercise intolerance
- SOB
- Poor weight gain
- Harsh systolic murmur
- Very high pulmonary blood flow
- Usually asymptomatic if small
What might VSD lead onto?
Eisenmenger’s syndrome
What are the investigations and treatment for VSD?
- Investigations: echocardiogram, ECG, CXR
- Tx: small asymptomatic = no intervention. Larger + symptoms = consider surgical repair
Describe Eisenmenger’s syndrome. What is its physiology?
- When shunting through septal defect is from right to left, resulting in deoxygenated blood in the systemic circulation
- High pressure pulmonary blood flow damages pulmonary vasculature -> there is increased resistance to blood flow (pulmonary hypertension) -> RV pressure increases -> shunt direction reverses (RV to LV) -> CYANOSIS!
Describe 3 risks associated with Eisenmenger’s syndrome.
- Risk of death
- Endocarditis
- Stroke
What is atrial septal defect?
An abnormal connection between the two atria; it is fairly common
Would a baby born with ASD be cyanotic?
No. There is a higher pressure in the LA than the RA and so blood is shunted from the left to right, therefore not cyanotic
What are the signs of ASD?
- Significant increase in blood flow through the right heart and lungs - pulmonary flow murmur
- Enlarged pulmonary arteries
- Right heart dilatation
- SOBOE
- Increased chest infection
- Ejection systolic murmur on auscultation
What are the investigations and treatment of ASDs?
- Investigations: echocardiogram, ECG, CXR
- Treatments: most close spontaneously, some require corrective closure
What is AVSD?
Atrio-ventricular septal defects. Basically a hole in the very centre of the heart. Involves the ventricular septum, the atrial septum, the mitral and tricuspid valves
Give 2 clinical signs of AVSD.
- Breathless
- Poor feeding and poor weight gain
What is a patent ductus arteriosus?
- A patent ductus arteriosus (PDA) occurs when it fails to close - the ductus arteriosus is a vascular foetal structure that connects the pulmonary artery and the aorta and usually closes in the first 48 hours after birth
- Persistence of the ductus arteriosus can result in heart failure, increased pulmonary pressures, and endarteritis
What are the signs of a patent ductus arteriosus?
- CONTINOUS ‘MACHINERY’ MURMUR
- Torrential flow from the aorta to the pulmonary arteries can lead to pulmonary hypertension and RHF
- Breathless
- Poor feeding, failure to thrive
- May be asymptomatic
What are the investigations of patent ductus arteriosus?
- Investigations: echocardiogram, ECG, CXR
- Treatment: varies. Surgical closure
What is the coarctation of the aorta? Describe its pathophysiology.
- Narrowing of the aorta at the site of insertion of the ductus arteriosus
- Excessive sclerosing that normally closes the ductus arteriosus extends into the aortic wall leading to narrowing