Hypertension Flashcards
What is the NHS health check?
A free check-up of your overall health and identifies any risk factors you might have for health problems.
What specific health problems does it calculate the risk for?
- heart disease, diabetes, stroke (cardiovascular risk)
- kidney disease
- dementia
What happens at an NHS health check?
- History
- Measurement of height + weight
- BP reading
- Blood test
What are the effects of hypertension on the brain?
- Transient Ischaemic Attack
- Stroke
What causes a TIA?
An embolus that briefly blocks blood supply causing a mini-stroke which lasts for less than 24hrs.
What are the 2 main types of stroke?
- Haemorrhagic: damage to blood vessels leading to rupturing of an artery
- Ischaemic: reduction in blood supply to brain due to clot etc.
What are the effects of hypertension on the eyes?
- Hypertensive retinopathy
- Optic neuropathy
What is hypertensive retinopathy?
Damage to the blood vessels feeding the retina due to the hypertension.
What are the signs of retinopathy?
- microaneurysms
- ‘cotton wool’ spots
What is optic neuropathy?
Blurring of the disc margin due to damage to the optic nerve caused by a lack of blood supply to it.
What are the signs of optic neuropathy?
- angiogenesis of new vessels across the optic disc (leading to blurring)
- disc becomes paler
What are the effects of hypertension on the heart?
- hypertrophy
- coronary heart disease
Why does hypertrophy occur?
There is increased vascular resistance so the heart tries to adapt by growing muscle. This is inefficient and can progress into heart failure.
What primarily causes coronary heart disease?
atherosclerosis in the coronary vessels
What are the effects of hypertension on the kidneys?
- Glomerulosclerosis
- Kidney failure
What is Glomerulosclerosis?
Narrowing and hardening of the the blood vessels that make up the glomerulus.
How does high BP cause aneurysms?
- Hypertension stretches the blood vessels.
- This makes the walls weaker and more friable.
- This increases risk of aneurysms.
How is hypertension managed in a GP setting?
- Recheck BP
- 24hr ambulatory BP monitoring
- Give lifestyle advice
- Recheck BP
- Start medications
What is 24hr ambulatory BP monitoring?
BP monitoring done at home
Why is 24hr ambulatory BP monitoring carried out?
It mitigates white coat hypertension (patients naturally feel more stressed when seeing a doctor)
What kind of lifestyle advice may be given?
- reduce obesity
- encourage aerobic exercise -> this will increase blood flow to muscles, skin and kidneys
- restrict salt intake
According to NICE guidelines, what should all people with hypertension be offered?
- test for proteinuria with urine sample
- blood test for HbA1c, eGFR, cholesterol
- fundoscopy for retinopathy (use light to look into eye)
- 12 lead ECG
What does the P wave denote?
Positive deflection caused by atria depolarisation
What does the Q wave denote?
Small negative deflection as the electrical signal move through (horizontally) the slow myocytes in interventricular septum.
What does the R wave denote?
Positive deflection caused by depolarisation in the apices of the ventricles.
What causes the S wave?
Negative deflection caused by depolarisation of the rest of the ventricles (which is in opposite direction to Lead II).
What causes the T wave?
Ventricles repolarise (the ventricular cells’ MP need to become negative again) and so even though the wave is travelling away from Lead II, it is a positive deflection. It is slower and more spread out
What is the PR interval?
Time between the beginning of atrial depolarisation and ventricular depolarisation. Delay at AV node with no depolarisation occurring to allow atria to fully contract (flat line) ~3/4 small boxes.
What is the QT interval?
It represents ventricular systole.
What does the QT interval depend on?
HR -> if rate increases, the QT interval decreases -> Corrected QT interval
What are the main nodes in the RA?
- Sino atrial node
- Atrioventricular node -> conduction velocity decreases as the cells have smaller diameters and slower ion channels. This causes a delay in ventricular filling
What is the main node in the LA?
Bachmann’s bundle (receives signals from RA)
What are the fibres in the interventricular septum called?
Bundle of His -> purkinje fibres
Why is the R wave peak bigger than the P wave?
There is a lot of muscle and electrical activity in the ventricles, over a short period of time.
Why is the T wave smaller than the R wave?
The electrical signal for repolarisation is more spread out -> it occurs over a longer period of time.
What are the leads of an ECG?
- x4 Limb leads (which make up leads I,II,III, AVL, AVR, AVF)
- x6 chest/ precordial leads (V1-V6)
What are the inferior leads?
II, III, AVF
Which coronary artery are the inferior leads associated with?
Right coronary artery
What are the lateral leads?
I, AVL, V5, V6
Which coronary artery are the lateral leads associated with?
Left circumflex artery
What are the septal leads?
V1, V2
Which coronary artery are the septal leads associated with?
Left anterior descending artery
What are the anterior leads?
V3, V4
Which coronary artery are the anterior leads associated with?
Left anterior descending artery
What is an ectopic pacemaker?
Nodes that can act as the pacemaker if the SA node fails. This includes…
- bachmann’s bundle
- AVN cells
- pacemaker cells in purkinje fibres
How do you describe ECGs?
- Check patient details
- Check calibration of ECG (position of patient)
- Rate
- Rhythm (distance between the peaks)
- Cardiac axis
- Look at individual waves and any elevations/depressions
What does a higher-than-average QRS complex suggest?
Greater muscle mass -> Left ventricular hypertrophy, prolonged hypertension
What causes inversion of T waves?
Cardiomyopathy (hypertrophy) causing abnormal depolarisation
How can you differentiate between MI and Left ventricular hypertrophy?
- look for biomarkers of MI (i.e. troponin)
- clinical history + symptoms
- concerning ST elevation
What can cause slight ST elevation in people not suffering from MI?
Inappropriate repolarisation
Are the effects of significant hypertension (pathological hypertrophy) reversible?
No -> their baseline ECG will look abnormal for the rest of their lives so it is important to always refer to their baseline ECG before making comments on new ECGs.
What roles does the sympathetic NS play in hypertrophy?
- RAS activation; further vasoconstriction
2. Insulin, growth factor, lipid release
What are the first line anti-hypertensives for those aged 55 or over?
Calcium channel blockers e.g. amlodopine
What are the first line anti-hypertensives for those from african-caribbean backgrounds?
Calcium channel blockers e.g. amlodopine
What is the recommended dosage for amlodopine?
5mg once daily -> 10mg
If this doesn’t work, what is the second line?
CCB + ACEi/ ARB/ Thiazide diuretics
What are the first line anti-hypertensives for those with diabetes/ <55yrs / non african-carribean origin?
ACEi/ ARB
If this doesn’t work, what is the second line?
ACEi/ ARB + CCB/Thiazide diuretics
Why are CCB first line for african-carribean patients?
- they have increased salt sensitivity (BP rises more easily in response to high salt)
- This leads to reduced renin responsiveness (ACEi are less effective initially).
How do CCB work?
- They block L type calcium channels on vascular smooth muscle.
What are the effects of blocking the calcium channels?
- ⬇️ amount of calcium entering smooth muscle cells
- ⬇️ activity of myosin -> less cross-bridging
- ⬇️ contraction of smooth muscle (vasodilation)
- ⬇️ peripheral resistance
Why can BP remain high even after taking medication?
- lack of adherence due to side effects/ lack of proper education/ life
- secondary causes which maintain high BP
- drug interactions reducing efficiency
- dose may not be high enough
- white coat syndrome
- ethnicity
