Cardiovascular Flashcards
What is atherosclerosis?
- principal cause of heart attack, stroke and gangrene
- plaque rupture leading to thrombus formation, partial/complete arterial blockage leading to a heart attack
Risk factors for atherosclerosis?
- Age
- smoking
- obesity
- high serum cholesterol
- diabetes
- hypertension
- family history (don’t understand it)
Where are atherosclerotic plaques found?
Peripheral and coronary arteries
What affects distribution of atherosclerotic plaques?
- haemodynamic factors
- changes in flow/turbulence
- cause artery to alter endothelial cell function
- wall thickness changes -> neointima
What is the structure of a atherosclerotic plaque?
- lipid
- necrotic core
- connective tissue
- fibrous ‘cap
(tunica media thins)
What is the response to injury hypothesis?
- injury to endothelial cells
- lead to endothelial dysfunction
(LDL enters through vessel walls making them sticky) - signals sent to circulating leukocytes
- leukocytes accumulate and migrate into vessel wall
- inflammation ensues
How are leukocytes recruited to vessel wall and what chemicals is it governed by?
- Wall is sticky so captured
- roll along wall slower and slower (selectins)
- firm adhesion (interns and chemoattractants)
- transmigration through vessel wall
What is the progression of atherosclerosis?
- Fatty streaks
- Consist of aggregations of lipid–laden macrophages and T lymphocytes within the intimal layer of the vessel wall - Intermediate lesions
- Lipid laden macrophages (foam cells)
- Vascular smooth muscle cells
- T lymphocytes
- Adhesion and aggregation of platelets to vessel wall
- Isolated pools of extracellular lipid - Fibrous plaques or advanced lesions
- impedes blood flow
- prone ot rupture
- covered by dense fibrous cap made of ECM (collagen + elastin) - Plaque rupture
- fibrous cap has to be resorbed and redeposited in order to be maintained
- if balance shifts in favour of inflammatory conditions, cap becomes weak + plaque ruptures
- thrombus formation
OR
5. Plaque erosion
- hard to tell the difference, not as severe
- clot usually lies above erosion
What is the treatment for coronary artery disease?
- Percutaneous Coronary Intervention (PCI)
- stent (steel) with drugs (sirolimus) that prevent restenosis
What is the role of aspirin?
- NSAID
- Antiplatelet
- irreversible inhibitor of platelet cycle-oxygenase
- blocking formation of thromboxane A2
- producing an inhibitory effect on platelet aggregation
What is the role of Clopidogrel/ticagrelor?
Antiplatelet = stops platelets sticking together and forming a clot
inhibitors of the P2Y12 ADP receptor on platelets and other drugs with antiplatelet actions
What is the action of statins?
inhibit HMG CoA reductase, reducing cholesterol synthesis
What is the action of PCSK9 inhibitors?
monoclonal antibodies that inhibit PCSK9 protein in the liver which leads to improved clearance of cholesterol from the blood
What do anticoagulants do? Give some examples
Anticoagulants work by preventing the formation of blood clots. They do this by *Inhibiting thrombin in the body that are involved in the clotting process
Eg Warfarin, Heparin
What are the clinical classifications for unstable angina?
- cardiac chest pain at rest
- cardiac chest pain with crescendo pattern
What are the clinical symptoms classification of myocardial infarction?
- cardiac chest pain
- unremitting
- occurs at rest
- sweating, breathlessness, nausea and/ or vomiting
What is the management for chest pain?
- Paramedics -> of ST elevation contact primary PCI centre for transfer
- take aspirin 300mg immediately
- pain relief
- oxygen therapy if hypoxic
- aspirin +/- platelet P@y12 inhibitor
- consider beta blocker
- consider other antianginal therapy
- coronary angiography (if troponin elevated)
What is the main cause of Acute Coronary Syndrome?
Plaque rupture
What is troponin?
- protein complex regulates actin:myosin contraction
- highly sensitive marker for cardiac muscle injury
- positive in pulmonary embolism, myocarditis, heart failure, arrhythmias, cytotoxic drugs
(not specific for ACS - goes up in exercise too!)
How do you treat NSTEMi and STEMi differently?
STEMI - urgently put a stent in as it implies continued damage to blood vessels
NSTEMI - not as urgent, so can do coronary angiography
What factors affect response to clopidogrel?
- dose
- age
- weight
- disease states such diabetes mellitus
- drug interactions
- genetic variants: CYP2C19
What would a STEMI look like on an ECG in the first few hours after symptoms present?
ST elevation
Tall t-waves
What would a STEMI look like on an ECG a few days after symptoms started?
Inversion of T-waves and presence of pathological q waves
What would a NSTEMI look like on an ECG?
ST depression; this indicates a worse prognosis
○ Transient ST elevation
○ T-wave changes.
(Be aware that the ECG may be normal in more than 30% of patients.)
How would you diagnose an NSTEMI with a normal ECG?
Perform a blood test. Troponin above the 99th percentile. Recommended to do 2 tests 2 hours apart and measure the difference
What leads of an ECG represent the septal view of the heart?
V1 and V2
What leads of an ECG represent the anterior view of the heart?
V3: anterior view of the heart
V4: anterior view of the heart
What leads represent the inferior view of the heart?
V5: lateral view of the heart
V6: lateral view of the heart
Lead I: lateral view
aVR: lateral view
aVL: lateral view
What leads represent the inferior view of the heart?
Lead II
Lead III
aVF
What are the two types of cardiac myocytes?
- Atrioventricular conductions system (slightly faster conduction)
- General cardiac myocyte
What is the result of left and right sided cardiac failure?
Right = venous hypertension and congestion
Left = pulmonary congestion and then overload of right side
What is the effect of patent foramen oval?
- defect in central septum
- eventually produces cardiac arrhythmias, pulmonary hypertension, right ventricular hypertrophy and cardiac failure
What are the complications of patent ductus arteriosus (PDA)?
- unusual after birth, breathing closes it
- left right side shunting overloads lung circulation with pulmonary hypertension
and right side cardiac failure
What is tetralogy of fallot and its complications?
4 main features
1. pulmonary stenosis (narrowing of valve to lungs)
2. ventricular septal defect
3. extraposition/overriding ventricular septal defect/aorta (aorta above VSD so more deoxygenated blood enters circulation)
4. right ventricle hypertrophy
right ventricle blood is shunted into the left heart producing cyanosis (blue lips) from birth
What is a ‘fallot spell’?
When a baby with tetralogy fallot starts feeding,
RV deoxygenated blood is shunted to LV
Deoxygenated blood is then pumped around the body
Causes baby to look blue
What is the treatment of tetralogy of fallot? And complications?
surgical repair of ventricular septal defect
- can leave scar tissue on right ventricle causing problems later down the line (ventricular tachycardia)
- pulmonary valve regurgitation (often replaced)
What is happening in ventricular septal defect?
- most common of congenital heart problems
- abnormal connection between 2 ventricles
- High pressure LV
- low pressure RV
- Blood flows from high pressure to low pressure chamber
- so NOT BLUE
- increased blood flow through lungs
What are the complications of large VSD?
- increased respiratory rate
What is the eisenmengers syndrome?
- high pressure pulmonary blood flow from VSD
- damages to delicate pulmonary vasculature
- resistance to blood flow through the lungs increases
- RV pressure increases
- shunt direction reverse
- patient becomes BLUE
- permanent high blood pressure
What is the most common type of atrial septum defect?
- secondum (middle of atrial septum - 90%)
What is the physiology of an atrial septal defect?
- higher pressure in LA than RA
- shunt is left to right
- increased flow into right heart and lungs
(if large hole causes RH dilation)
What are the clinical signs of atrial septal defect?
- pulmonary flow murmur
- fixed split second heart sound
- big pulmonary arteries on CXR
- big heart on CXR
What is the physiology of an atrio-ventricular septal defect?
- involves the ventricular septum, atrial septum, mitral and tricuspid valves
- one big AV valve instead of two
What is the physiology of the patent ductus arteriosus?
- shunted flow from pulmonary artery to aorta
What is complete transposition of the great arteries (TGA)?
- aorta coming off the right ventricle and the pulmonary trunk off the left ventricle
- male and diabetes
What is coarctation of the aorta?
- secondary to an excessive obliterating process that normally closes ductus arteriosus (when baby takes first breath)
- result is a narrowing of the aorta just after the arch
- excessive blood flow being diverted through the carotid and subclavian vessels to supply rest of body
What are clinical signs of coarctation of the aorta?
- can stop blood flow to left arm so left arm might have high blood pressure but right arm is normal
What is bicuspid aortic valve?
- either only have 2 flaps instead of 3 OR 2 of them have fused together
- degenerate quicker
- aorta more prone to aneurysm (>55m operate)
What is the Fontan procedure?
- for heart with only one usable ventricle
- replum heart to form a passive venous circuit
- passive connection of great veins to the pulmonary artery
- uncertain long term
What is endocardial fibroelastosis?
secondary = a frequent complication of congenital aortic stenosis and coarctation
- lots of dense collagen and elastic tissue deposited on left ventricle -> increased stiffening of the heart
What is dextrocardia?
- heart positioned more on right side of body
What is an aneurysm?
Dilation of part of the myocardial wall
- dilation of the walled sac allows blood stasis and thrombosis
What is cor pulmonale?
Right ventricular hypertrophy and dilatation due to pulmonary hypertension
How does acute rheumatic fever affect the heart?
- development of immunity against the Group A beta-haemolytic Strep infection produces antibodies that cross react with cardiac myocytes producing localised inflammation and subsequent scarring
What is mitral valve disease?
calcification of the mitral valve
- usually asymptomatic
- unless had previous valvular disease or inflammation
What is mitral valve prolapse?
- degeneration of the mitral valves
- inner fibrous layer becomes loose and fragmented
- valve doesn’t close properly
What are the causes of myocarditis?
- viruses
- rickettsia
- bacteria
- fungi
- metazoa
- hypersensitivity
- radiation
What is giant cell myocarditis?
- aggressive form of cardiac disease with areas of muscle cell death due to macrophage giant cells
What are cardiomyopathies?
Primary heart diseases mainly caused by genetics
- inherited
What are the different types of cardiomyopathy?
- Dilated cardiomyopathy (DCM) - dilated heart
- Secondary dilated cardiomyopathy -> drugs, pregnancy - Hypertrophic cardiomyopathy (HCM) - asymmetric hypertrophy with distortion of a papillary architecture
- Arrhythmogenic right ventricular cardiomyopathy (ARVC) - progressive dilation of right ventricle with fibrosis
- Restrictive cardiomyopathy - poor dilation of heart, reduces blood flow to body
What is hypertrophic cardiomyopathy caused by?
Sarcomeric protein gene mutations
- causing myofibril disarray/disorganisation
What is dilated cardiomyopathy caused by and its consequences?
Cytoskeletal gene mutations
Presents with heart failure symptoms
(in young people who you wouldn’t expect to have heart failure)
What causes arrhythmogenic cardiomyopathy?
Desmosome gene mutations
- programmed replacement of heart muscle (destroys muscle)
- cause arrhythmia
What are channelopathies?
Diseases in channel gating currents for Na, K or Ca
- long QT syndrome
- affect heart contractions
- normal structure of heart
What are some types of channelopathies?
- Long QT syndrome
- Short QT syndrome
- Brugrada syndrome
- CPVT - Catecholaminergic polymorphic ventricular tachycardia
- Wolff Progressive Syndrome
What is a very likely cause of a heart attack in healthy young people?
Inherited heart conditions
What is Marfan’s disease and how can it cause heart problems?
- Genetic disease affecting connective tissue
- can cause dilation of aorta
What is familial hypercholesterolaemia and how does it cause heart problems?
- problem with LDL receptor
- not affected by diet, purely genetic
- features of cholesterol deposits on hands and eyes
- increase massively atherosclerosis + CHD
What is cardiac myxoma?
- most common cardiac tumour
- bias towards atria
What is cardiac tamponade?
Compression of the heart leading to acute cardiac failure following bleeding into the pericardial space
What is haemopericardium?
Direct bleeding from vasculature wall through the ventricular wall following MI
What is vasculitis?
An inflammatory and variably necrotic process centred on the blood vessels that may involve arteries, veins or capillaries
What is polyarteritis nodosa (PAN)?
- more in males
- patchy necrotising inflammation of medium muscular arteries
What is hypersensitivity angitis?
- presents with palpable purpura on legs (red/purple spots)
- caused by bacterial or viral infections
- resulting in inflammation of the smallest arteries and arterioles
What is churg-strauss syndrome?
- granulomatous inflammation of blood vessels with intense eosinophilic infiltrates
- strong association with asthma
What is giant cell arteritis?
- commonest type of vasculitis of large vessels
- or temporal arteritis
- inflammation of blood vessels mainly in temporal arteries
(can result in blindness if not treated)
What are different types of aneurysms?
- abdominal aortic aneurysm
- berry aneurysm
- dissecting aneurysm (splits arterial wall)
What are different types of vascular tumours?
- haemngioma = benign proliferation of blood vessel tissue
- glomus tumour = a benign neoplasm under nails or on foot
- haemangioendothelioma = tumours of endothelial cells
- angiosarcoma = neoplasm of endothelial cells
- kapsosi sarcoma = HIV/AIDs
What is an embolism?
The passage of material through the venous or arterial circulations
What are different types of embolisms?
- air embolism
- acute decompression sickness
- amniotic fluid embolism
- fat embolism
- bone marrow embolism
What are the risk factors of IHD?
- age
- smoking
- family history
- diabetes mellitus
- male
- hyperlipidemia
- kidney disease
- obesity
- physical inactivity
- stress
What are the exacerbating factors for supply and demand for angina?
Angina is the mismatch of oxygen supply and demand
Supply:
- anemia
- hypoxemia
Demand:
- hypertension
- tachyarrhythmia
- valvular heart disease
What environmental factors cause IHD?
- exercise
- cold
- heavy meals (blood diverted to the gut)
- emotional stress
Other than limitation of supply what else causes angina?
- Impairment of blood flow by proximal arterial stenosis
- Increased distal resistance eg left ventricular hypertrophy
- Reduced oxygen-carrying capacity of blood eg anemia
What are the different types of angina?
- crescendo angina - increases gradually over months
- unstable angina -
- prinzmetal’s angina - coronary spasm (v. rare)
- microvascular angina - angina with apparently normal coronary arteries
How are IHD symptoms different to heart failure?
Both: chest pain and breathlessness
Heart failure: no fluid retention, palpitation, syncope
What are different diagnoses for chest pain?
Pericarditis/ myocarditis
Pulmonary embolism/ pleurisy
Chest infection/ pleurisy
Gastro-oesophageal (reflux, spasm, ulceration)
Musculo-skeletal
Psychological
Dissection of the aorta
What investigations can you do for stable angina?
- CT coronary angiography
- exercise testing and watch ECG
- movies scan
- stress scan (see which regions of heart doesn’t function properly)
- coronary angiography (cameras in coronary arteries)
What are the drugs for stable angina?
- beta blockers
- nitrates = GTN (reduce pain)
- statin (lower blood cholesterol)
- aspirin (anti platelet - with a stent)
- calcium channel blockers
- ACE inhibitors (reduce BP, relaxation of blood vessels)
What are the side effects of beta blockers?
- tiredness, nightmares
- don’t give to asthma (blocks receptor in the lungs)
- erectile dysfunction
- cold hands and feet
- bradycardia
What is the function of nitrates?
Venodilators
- venous capacitance dilate
(give headache at first)
What are the pros and cons of PCI and CABG (bypass)?
PCI:
pros
- less invasive, convenient, repeatable, acceptable
Cons:
- risk stent thrombosis + restenosis
CABG
pros: prognosis, deals with complex disease
Cons: invasive, risk of stroke, bleeding, can’t do if frail, length of stay, time for recovery
What causes elevation and depression in an ECG?
depolarisation moves towards an electrode = positive elevation
depolarisation moves away = negative depression
When does the atrium repolarise on a ECG?
During QRS complex but cannot be seen as ventricle depolarisation is greater
What do all the parts of the ECG signify?
P wave = atrial depolarisation
PR interval = Electrical impulse held at AV node
QRS complex = ventricle depolarisation
ST = depolarisation complete
T wave = ventricle repolarisation
What does a short PR interval represent?
- early activation of the ventricle
What does a long PR interval represent?
First degree heart block
How do you determine the heart rate on an ECG?
Rule of 300/1500 = 10s rule
Count number of big boxes between 2 QRS completes and divide 300 by that number
(if not regular count number of complexes and multiply by 6)
What are the causes of pericarditis?
- viral (common) - enteroviruses
- bacterial
- autoimmune (common)
- neoplastic (secondary metazoic tumours)
- metabolic (uraemia)
- traumatic and iatrogenic (e.g. pacemaker lead insertion)
What 3 things control blood pressure?
- Cardiac output + peripheral resistance
- interplay between RAAS and SNS (sympathetic)
- Local vascular vasoconstrictor and vasodilator mediators
How does RAAS and SNS affect blood pressure?
Both increase peripheral resistance
How can we interfere with RAAS and SNS systems to reduce blood pressure?
- ACE inhibitor - stops angiotensin II being formed
- Calcium channel blockers - vasodilators, reducing perisperhal resistance
- Beta blocker - slow heart beat affecting cardiac output
- alpha blockers - reduce peripheral resistance
- Renin inhibitor
- Aldosterone antagonist
When are ACE inhibitors used? Example?
- hypertension
- heart failure
- diabetic nephropathy
end in ‘pril’ e.g. ramipril
What are the adverse effects of ACE inhibitors?
- Related to reduced angiotensin II formation
- hypotension (over do it)
- acute renal failure (used in kidneys)
- hyperkalaemia (link to aldosterone –> cause potassium excretion)
- teratogenic effects in pregnancy (important in fetal development) - Related to increased Kinin production (ACE also breaks down bradykinin -> cause these symptoms)
- cough
- rash
- anaphylactoid reactions
What is angiotensin II receptor blockers used for?
- hypertension
- diabetic neprhopathy
- heart failure (when ACE-i contraindicated)
end in ‘sartan’
What are the adverse effect of angiotensin II receptor blockers?
- symptomatic hypotension (especially volume depleted patients - as angiotensin regulated there volume)
- hyperkalaemia
- potential for renal dysfunction
- rash
- angio-oedema
- don’t give to pregnant women
generally very well tolerated
When are calcium channel blockers used? Example?
- hypertension
- ischaemic heart disease (angina)
- arrhythmia
mostly end in ‘pine’ e.g. amlodipine
What are the 3 main types of calcium channel blockers?
- Dihydropyridines e.g. amlodipine
- target peripheral resistance - Phenylalkylamines - verapamil
- target heart mainly, slows HR, reduce contraction force - Benzothiazepines - diltiazem
- intermediate heart/peripehral vascular effects
What are the adverse effects of calcium channel blockers?
- DUe to peripheral vasodilation
- flushing, headache, oedema, palpitations (body increases CO to increase blood pressure) - Due to negatively chronotropic effects
- bradycardia (slow HR)
- atrioventricular block - Due to negatively inotropic effects
- worsening of cardiac failure
When are beta adrenoceptor blockers used ?
- ischaemic heart disease (angina)
- heart failure
- arrhythmia
- hypertension
end in ‘Prolol’ e.g. bisoprolol
Are beta blockers selective?
Some are more selective then others
How do beta blockers affect asthma patients?
Affect beta 2 receptors in the lungs
- can cause asthmatic attack
What are the adverse effects of beta blockers?
- fatigue (from reduced adrenaline)
- headache
- sleep disturbance/nightmares
- bradycardia (slow HR)
- hypotension (from slow HR)
- cold peripheries
- erectile dysfunction (
worsening of: asthma, COPD (allowed to have it unlike asthmatics), PVD, heart failure (need to give dose slowly)
What are the benefits of water soluble diuretics?
- less likely to enter the brain > less sleep disturbances + nightmares
- excreted by kidney
When are diuretic used?
Act on kidneys to increase excretion of water and sodium (has affect on ion channels and heart)
- hypertension
- heart failure
What are the 4 classes of diuretics? Examples?
- thiazides and related drugs (distal tubule) e.g. bendroflumethiazide
- Loop diuretics (loop of Henle) e.g. furosemide
- potassium sparing diuretics e.g. spironolactone
- Aldosterone antagonists
What are the adverse effects of diuretics?
- hypovolaemia + hypotension (reduced volume in blood)
- low serum K, Na, Mg, Ca
- raised uric acid (gout)
- erectile dysfunction (mainly thiazides)
- impaired glucose tolerance
What are the treatment steps for hypertension of someone under 55 yrs?
- ACE-i or angiotensin II receptor blocker
- ACE-i or ARB + CCB
- AND thiazide like diuretics
- resistant hypertension = spironolactone, high dose TLD, alpha blocker, beta blocker