Heart Lectures Flashcards
BP = ?
BP = CO x SVR
What determines 85% of systemic vascular resistance?
Pressure in the pre-capillary arterioles
Describe the RAAS system
What controls BP?
Hormonal influences (RAAS and SS)
Neurological control
What does SS activation of the following receptors do?
- α 1 receptors in systemic arterioles
- β 1 receptors
- β 2 receptors in musculature arterioles
α 1 = vasoconstriction of systemic arterioles
β 1 = inc force and rate of heart contraction
β 2 = vasodilation of arterioles in muscles
What is NOR an agonist of?
Mostly α receptors
What is ADR an agonist of?
α and β receptors
Where are baroreceptors for neurological control of BP found?
Carotid sinus
Aortic arch
What can cause secondary HT?
What causes primary HT?
Which drugs can cause HT?
Oral contraceptives
NSAIDs
Corticosteriods
OTC decongestants
Stimulant recreational drugs
Hermal remedies
Some SSRIs - Venlafaxine
How can you tell if a P has renal artery stenosis clinically?
Bruit of the renal artery?
Sudden deterioration of renal function after starting ACEIs
Flash pulmonary oedema
How is renal artery stenosis treated?
Standard medical treatment is first line
If it doesn’t respond - can consider renal artery stenting
How do you treat HT with CKD?
Aggressive standard medical Rx - aim to get BP <130/80
Which drugs can reduce CKD progression?
What do you need to beware of when using these drugs?
ACEIs
Need to beware of using with drugs that exacerbate hyperkalaemia as ACEIs block aldosterone (aldosterone inc Na reabsorption and expense of K+ which is excreted in the urine - this is prevented with ACEIs = hyperkalaemia)
Which diuretic can cause hyperkalaemia?
Spironolactone
Which diseases are phaechromocytoma associated with?
Neurofibromatosis
Multiple Endothelial Neoplasia Type 2
What are the symptoms of a pheochromocytoma?
Anxiety, palpitations, tremor, sweating, headache, diarrhoea, Raynaud’s, chest pain
Catecholamines are secreted in bursts - therefore symptoms occur in “attacks”
What are the signs of a pheochromocytoma?
HT - ?postural hypotension
Tachycardia, fever, glycosuria, pallor, flushing
What are the tests for phaechromocytoma?
24hr urinary catecholamines
CT / MRI
PET scan
What is the Rx for a phaemochromocytoma?
α and β blockade
Can do surgical excision
What causes Cushing’s disease?
Pituitary adenoma secreting ACTH
When should you suspect Cushing’s
Obese with thin skin & easy bruising
Proximal myopathy
Low K+ and high Na+
What are the tests for Cushing’s?
24hr urinary cortisol
Low dose dexamethasone suppression test
Dexamethasone is a man-made version of cortisol. After you take a dose of it, your body should make less cortisol. That’s the idea behind the test – take some dexamethasone and see whether your cortisol level drops.
In the adrenal gland, where do the following come from?
- Catecholamines
- Cortisol
Catecholamines = medulla
Cortisol = adrenal cortex
What causes Conn’s syndrome?
Adenoma or hyperplasia of the adrenal cortex
When should you suspect Conn’s syndrome as a cause of HT?
If the P has HT and low K+ (beware if on drugs which lower K+; also beware if on drugs that raise K+ back to normal ranges)
Also if there is a high aldosterone:renin ratio
How is Conn’s diagnosed and treated?
Diagnosed = CT or MRI, or venous sampling from the adrenal veins
Tx = spironolactone, adrenalectomy if unilateral
Where is aortic coarctation usually found?
Distal to left subclavian artery
How is aortic coarctation recognised clinically?
Weak femoral pulses
Radio femoral delay
Palpable collaterals over posterior ribs (can appear as notching on ribs on XRAY)
Murmur of AR
How is aortic coarctation diagnosed?
CT or MR aortography
What is the protocol for treating HT in the following Ps:-
- Clinic BP under 140/90
- Clinic BP between 140/90
- Clinic BP over 180/120
> 140/90 = offer ABPM or HBPM
If >80 and >150/90 - lifestyle advice and poss drug Rx
If 80-40 = lifestyle advice and drug Rx
> 180/120 = assess for target organ damage. If none - repeat within 7 days, give ABPM or HBPM.
If retinal haemorrhage, papilloedema, life-threatening Sx or suspected pheochromocytoma - needs same day specialist review!
What is the second commonest cause of HF?
HT
What are the possible effects of chronic HT?
Heart muscle damage
Large vessel damage (AA, CVD, CAD, PVD)
Micorvascular damage (CKD, brain dysfunction, exacerbation of diabetes effects)
What are the acute effects of severe HT?
What lifestyle advice for HT should you give in relation to:
- Alcohol
- Salt
- Exercise
- Smoking
- Caffeine
What lifestyle advice for HT should you give in relation to:
- Weight
- Diet
What physical things should you examine in a P with HT?
How is hypertensive retinopathy graded?
What blood tests can indicate a high alcohol excess?
High MCV
High GGT
What is the second commonest cause of renal dysfunction?
HT
What blood tests should you do in HT?
How do
- Conn’s syndrome
- Cushing’s syndrome
- Acromegaly
appear on blood tests?
Conn’s = can cause low K+ and high aldosterone : renin ratio
Cushing’s = can cause high Na+ and low K+, can also cause high glucose
Acromegaly = can cause high glucose levels
What abnormalities can HT cause on an ECG?
Can cause LV hypertrophy
- get tall QRS complexes.
Can also cause lateral T wave inversion = strain pattern
May also cause LBBB
Which criteria is used to identify LV hypertrophy on ECG?
What do you need to remember about this criteria?
Sokalov-Lyon criteria
= Tallest R wave in V5 or 6 + S wave in V1 is greater than 35mm
Is not v sensitive - may be caused by young, thin Ps
Conversely - older and fatter Ps may not show these signs on ECG even though they have LVH.
What does this ECG show?
LV hypertrophy with strain - shows tall QRS complexes with lateral T wave inversion.
Name
- 3 ACEIs
- 2 ARBs
- 1 α blocker
- 3 β blockers
- 3 calcium channel blockers
- 1 direct acting vasodilator
- 2 nitrates
- 2 loop diuretics
- 1 thiazide like diuretic
- 1 thiazide diuretic
- 1 aldosterone antagonist
What is Step 1 of the hypertensive medication ladder?
If T2DM or <55 and not A/AC descent = ACEi or ARB
If >55 & no T2DM or A/AC descent = give CCB
What is Step 2 of the hypertensive medication ladder?
Add on an ACEi/ARB or CCB depending on what was used for Step 1
What is Step 3 of the hypertensive medication ladder?
ACEi or ARB + CCB + Thiazide-like diuretic
What is Step 4 of the HT medication ladder?
Confirm is elevated with A or HBPM
Get expert advice
- Can add spironolactone if K+ is <4.5 or an α or β blocker if blood K+ is >4.5
When is HT diagnosed as chronic or gestational in pregnancy?
Chronic HT if it occurs before 20w
Gestation if it occurs after 20w
When do you treat HT in pregnancy?
If >140/90
What drugs should you avoid to treat HT in pregnancy and why?
Need to avoid
- ACEIs
- ARBs
- Diuretics
They reduce placental blood flow
Which drugs are safe to treat HT in pregnancy?
Labetalol (α and β blocker)
Nifedipine (Ca channel blocker)
Methyldopa (acts on BP control centre in the medulla)
When is rapid HT control required?
If there is
- accelerated HT (headaches, visual disturbances)
- hypertensive encephalopathy
- acute HF (pul oedema)
- aortic dissection
- pre-eclampsia / eclampsia
What Rx is given for hypertensive emergencies?
IV Labetalol, Nitrate (GTN, isosorbide dinitrate) and sodium nitroprusside
Also - BP monitoring - dont want to reduce too fast - want to reduce over a period of time - immediate reduction
What did the seven countries study show regarding hyperlipidaemia?
That there was an exponential association between cholesterol levels in the blood and cardiovascular mortality
Rise from 4mmol to 8mmol linked to a 5fold inc in CHD mortality
What are the two pathways to make cholesterol in the body?
Exogenous = broken down from food taken in
Endogenous = made from HMG-CoA in the liver
Which enzyme is involved in making cholesterol in the liver?
HMG-CoA Reductase
How do statins work?
Inhibit HMG-CoA Reductase - thus reducing cholesterol by the liver.
Lowers LDL, total cholesterol and 3Gs, increases HDL
Which Rx is first line for Ps with elevated cholesterol?
What is good about this Rx?
Atorvastatin
Simvastatin
They have been proven to reduce all cause mortality in CVD.
Why do statins reduce all cause mortality?
As well as reducing cholesterol levels, they lower inflammatory cytokine levels in atherosclerotic plaques.
This prevents progression of atherosclerosis and stabilises the plaques that are already there.
What are statins used for in secondary prevention?
What dosage is used?
Used in Ps who have had a CVD to prevent recurrence = secondary prevention.
High dose starting therapy = Atorvastatin 80mg OD
What is the ideal lipid profile?
- Cholesterol
- LDL
- 3Gs
- HDL
- Total:HDL Ratio
Cholesterol <5
LDL <3
3Gs = 0.5-2
HDL = >1.5
Total: HDL ratio = <3.5
What can cause secondary dyslipidemia?
DM
Hypothyroidism
CKD
Chronic liver disease
Obesity
Smoking
Alcohol XS (inc 3Gs)
Medications (thiazide diuretics)
How does lifestyle advice differ from hyperlipidemia to HT?
Hyperlipidemia - advice omits any guidance about caffeine
When are statins recommended for primary prevention?
What Rx are Ps started on?
If the 10 year risk of CVD is >10% based on Q-risk
Start on Atorvastatin 20mg OD for 3months - aim for non-HDL reduction of >40%
If statins do not reduce cholesterol levels sufficiently, what other Rx can be considered?
Ezetimbe (inhibits absorption of cholesterol by small intestine)
Evolocumab (PCSK9 inhibitor - reduces cholesterol)
Bezafibrate (for high 3Gs - activates lipoprotein lipase)
On a parasternal long axis view of an echocardiogram - which chamber is
(a) most anterior
(b) most posterior?
Most anterior = right ventricle
Most posterior = left atrium
What views can be seen during an echocardiogram?
Parasternal long axis
3 x Parasternal short axis - aortic valve, mitral valve and heart muscle levels
Apical 4-chamber view
Apical 3-chamber view
How can you identify the aortic valve in cross section on an echo?
Looks like the Mercedes Benz sign
Which leaflet of the mitral valve is bigger - anterior or posterior?
Anterior leaflet has bigger area (approx twice as big)
Which chamber of the heart is often lacerated in stabbings?
Right ventricle
What causes aortic stenosis?
Calcium deposits on aortic valve leaflets
How is the doppler principle used in echo?
Can be used to calculate pressure differences between chambers, valve gradients, pulmonary artery pressures, right atrium pressure and to quantify intra-cardiac shunts
Apart from echo - what is another way to estimate right atrial pressure?
By the jugular venous pressure