L15 Cardiovascular diseases Flashcards
death rates and stuff with CVD
causes biggest amount of deaths
1 in 3 deaths are CVD
been a steady decline in deaths by CVD as treatments and lifestyle changes inc
major diseases that you need to know
Affecting the vessels
- hypertension
- stroke
- coronary heart disease
- thrombosis
Affecting the heart
- valvular disease
- arrhythmia
- myocardial infarction
- heart failure
diagram for what diseases affect bwhat part of the cardiac output,
see onenote
:)
HYPERTENSION: what bp counts as high blood pressure
over 140mmHg/90mmHg
how does hypertension affect afterload and therefore the SV
increases the afterload
which increases ESV
and thus decreased SV
see notes on bp regulation
how does hypertension affect filtration
increases filtration
can lead to oedema (increase in fluid)
see notes on capillary exchange
how many people on avg are affected by hypertension in UK
about 15mil people
and 1/3 of these usually goes undetected
what is the main thing that makes hypertension so dangerous
its a big risk factor for many diseases
how does hypertension lead to coronary artery disease & myocardial infarction
accelerates ATHEROSCLEROSIS
by increasing damage to endothelial walls of coronary arteries
what is artherosclerosis btw
thickening or hardening of the arteries caused by a buildup of plaque in the inner lining of an artery
how does hypertension lead to aneurysms
aneurysm is when weakness in blood vessel wall develops
so can bulge under pressure
increased wall stress
leads to aneurysms
and also makes it more liekly to rupture
what vessel is prone to aneurysm
aorta
what type of aneurysm can lead to stroke
saccular aeurysm - in the cerebral circulation
what are the 2 types of stroke
haemorrhagic - when a blood vessel inside the skull bursts and bleeds into and around the brain
and ischaemic - when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients
how does hypertension lead to stroke
damage to endothelial cells in the cerebral arteries
increasing atherosclerosis
which can lead to ischaemia by blocking arteries
or hamorragic by aneurysms that may form
how can hypertension damage the kidneys
can cause inc vasoconstriction of the renal arteries
and reduce blood supply to kidney
damaged the nephron and kidney function declines
causing chronic kidney disease
how can hypertension cause heart failure
chronic hypertension puts more strain on ventricles
by increasing afterload
and reducing cardiac output
the heart tries to compensate by hypertophy (when the organ literally increases in size via bigger cells)
this increases contractility
but it’s temporary and will decrease over time
Causes of hypertension:
2 classifications of causes - what is primary hypertension?
primary/essential hypertension:
= when no known cause
probs lots of contributing factors
e.g.
- genetic predisposition
- alcohol
- less excersise
- obesity
- diabetes
- intrauterine environment (maternal high bp can influence developing bp in later life)
Causes of hypertension:
2 classifications of causes - what is secondary hypertension?
when known medical cause of hypertension
e.g.
adrenal gland diseases
- pheochromacytoma (a tumour affecting this gland)
- leads to increased catecholamine production
- leads to more adrenaline circulating
how is chronic kidney disease a secondary cause of hypertension
chronic kidney disease
- less Na+ excretion
- more fluid retained
- so RAAS system is activated
(see BP reg notes)
- so inc vasoconstriction
how is endocrine disorders a secondary cause of hypertension
endocrine disorders
- diabetes (inc fluid, and inc arterial stiffness)
- cushings disease (when pituitary gland releases too much cortisol ie ACTH, and increased RAAS activation)
how is adrenal gland disease a secondary cause of hypertension
adrenal gland diseases
- pheochromacytoma (a tumour affecting this gland)
- leads to increased catecholamine production
- leads to more adrenaline circulating
treatment of hypertension: what are the 2 main things that treatments aim to fix for hypertension
reducing cardiac output
or
reducing vasocontriction
cuz BP = CO x total peripheral resistance
explain the 3 types of drugs that affect the RAAS system that is used to treat hypertension
all lead to RAAS inhibtion
- Angiotensin Converting Enzyme inhibitor (ACEi)
- Angiotensin II receptor blocker (ARB)
- these 2 both reduce vasoconstriction cuz angiotensin causes vasoconstric
- Aldosterone antagonist (Spironalactone)
- aldosterone stimulates Na+ and water reabsorption
- so when this is stopped, this reduces Na+ and water reabsorption
- reducing cardiac output
in treating hypertension, what do Ca2+ channel blockers do?
Ca2+ stiulates muscle contrarction
so this drug inhibits entry of Ca2+ into cardiac and vascular muscle cells
reducing contractility and strok volume
therefore reducing CO
in treating hypertension, what are thiazide diuretics
diuretics - effects kidney
this inhibits renal Na+ reabsorption
increasing water loss in uring
thus decreasing venous return
and EDV
reducing CO
in summary, what are the 3 main types of drugs used to treat hypertension
- RAAS inhibitors
- Ca2+ channel blockers
- thiazide diuretics
what are the levels and classes of drugs used to treat hypertension
1 drug = target angiotensin or Ca2+ blocker
if dont respond,
2 drugs = add in more angiotensin blocker, Ca2+ blocker or a thizide diuretic
if still dont respond,
3 drugs = all 3 classes of drugs
what is it called when the patient doesnt respond to all 3 classes of drugs?
resistant hypertension
add in aldosterone antagonist OR a beta blocker (which blocks sympathetic pathway)
this is last step
vascular disorders: ATHEROSCLEROSIS, what is it
narrowing of vessels,
fatty plaque narrow the blood vessel
what are the 2 main triggering factors for atherosclerosis
endothelial damage (BP, smokeing, diabetes)
high LDL cholesterol
describe plaque formation
the triggering factors increase the mrisk of inflammatory cells
e.g. macrophages and lipid accumulation
and fibrous tissure forms a little cap
and fatty streak which forms plaque
also thrombus formation because theres high chance of rupturing
this can lead to clot formation
see onenote for atherosclerosis diagram
:)
what ar the 2 circulations where this damage is most common
cerebral
coronary
Effects of atherosclerosis in coronary circulation
redued blood supply to myocardium
causes chest pains = angina pectoris
or
if complete blockage in vessel = ischaemic heart disease
Effects of atherosclerosis in cerebral circulation
complete cut off = stroke
partial cut off = brain cells die = vascular dementia
how do we treat therosclerosis
statins
inhibits cholesterol synthesis = lowers LDL
acc the most prescribed drugs in the uk
vascular diseases - THROMBOSIS, what is it
blood clots
what might cause thrombosis
static/low blood flow
e.g. immobility and atrial fibrilation (where heart rate is slower than avg)
where is thrombosis most likely to occur
in legs
cuz mobility helps venous return so immobility means skeletal muscle pumps not working
explain formation of thrombosis venous circulation
e.g. starts in leg
in immobility
swelling and thrombus forms usually in veins near valves
risk of part of this breaking off and embolise
to form embolus
this goes up minto the circulation back through heart
will be fine on the way to the heart cuz vessels get bigger
but when leaves the heart to the pulmonary circ
will evetually encounter vessel it cant get trhoguh
= pulmonary embolism
blood supply to lungs cut off vry bad
explain formation of thrombosis in arterial circulation
e.g. if atrial fibrilation - so blood flow in heart is not very good
thrombus happens in atria and breaks off
can go from L atrium to L ventricle
gets pumped into aorta
and get lodged
or could go into cerebral circ and cause stroke
or into coronary circulation and cause myocardial infarction
how do we treat thrombosis
anticoagulants:
e.g. warfarin
anti platelet therapy:
e.g. aspirin
cardiac disorders: CORONARY ARTERY DISEASE and myocardial infarction, what is it
biggest killer worldwide
starts with ATHEROSCLEROSIS of coronary artery
can restrict myocardial blood flow
can lead to angina (due to lack of O2)
what treatment for angina in CAD
GTN spray
basically nitric oxide - leads to vasodilation
what can the atheroscleorsis of coronary artey lead to
atherothrombosis
where the plaque ruptures or there’s an embolism
this causes the vessel to get completely cut off
leading to MI
any muscle that is supplied by the vessel that’s blocked starts to die pretty quickly
whats the most commmon vessel to be affected by this
the left anterior descending coronary artey
supplies the left ventricle
what is the treatment for myocardial infarction
percutaneous coronary intervention
= minimally invasive operation using catheter (inserted via femoral or radial artery)
inserts a stent to reopen blocked artery
and also given thrombolyitcs
= medication to break up clot
cardiac disorders - VALVULAR DISEASE, what are the 2 types
stenosis
and regurgitation
what is stenosis
thick/stiff valves that fail to open properky
this increases the afterload, reducing ejection
common cause of stenosis
rheumatic fever
these symptoms can appear years after infection
what can stenosis lead to
LV hypertrophy -> eventual heart failure
what is regurgitaion
valves fail to close properly
so backflow of blood
reduces stroke volume and cardiac output
treatments for valvular disease
surgery to repair valves
or can replace w/ sythetic valves
cardiac disorders- HEART FAILURE, what are the 2 types
heart cant keep up with body’s demands
normally is secondary to other diseases, e.g. hypertension or myocardial infarction
diastolic and systolic
what is diastolic heart failure
caused by thickening or stiff chambers in ventricles
so heart cant relax properly
and can’t fill with blood
this reduces EDV and reduces SV
what is sytolic heart failure
heart cant pump
stretched thin chambers
arent effecient at contracting
so reduced contractility and reduced SV
causes of heart failure
is secondary so
diseases that increase workload:
- hypertension
- aortic stenosis
causes pressure overload on ventricle
increases afterload
hypertrophy occurs and you get thinner walls and larger chambers
damage to myocardium -
after myocardial infarction
can happen years after
lose a lot of myocytes
so the rest of heart tissue has to work harder
myocytes arent replaced- instead you get a fibrous scar
leads to heart failure
how can heart failure affect pulmonary circulation
if left sided heart failure
then not enough blood pumping out of the aorta
causes a backflow through the LA and LV
means the blood in the pulmonary circ gets backed up also
inc pressure in pulmonary veins
causing pumonary oedema
which is why shortness of breath and coughing
how can heart failure affect systemic circ
right sided failure
blood pools in peripheral as increased pressure in systemic veins
= peripheral oedema
what is it caleld when heart failure affects both sides of heart
congestive heart failure
how does heart failure affect cardiac output and how is this a cycle
reduced cardiac output naturally leads to activation of RAAS and SNS
this might be alright short term but
it icreases the amount of fluid, vasoconstriction (thus resistance), and workload increases
this again reduces cardiac output cua the heart cant deal
how do we treat heart fialure then, 4 key treatments
no curative treatments
damaged myocardiocytes cant be replaced
but can use
> beta blockers
> anti-hypertensives
surgical:
> left ventricular assist device
> heart transplant
explain beta blockers in heart failure treatment
specifically beta adrenoreceptor antagonists
reduces SNS activity to reduce worload
and to prevent desensitisation (which tends to happen after constant activation of SNS, so this means when SNS is acc needed its sensitive to it)
explain anti hypertensives in heart failure treatment
same drugs used in hypertension treatment
reduces fluid to relieve symptoms
reduces vasoconstriction
reduces workload
explain left ventricular assist device and heart transplant as treatment
mechanical heart pump or transplant from healthy donor
but
surgical risks
immunorejection
also heart failure candidates usually older and frail so not good for these high risk surgeries
cardiac disorder: ARRHYTHMIAS, what is it
devation heart’s normal sinus rhythm
can be asymptomatic
or
palpitations, faitning, heart failure, cardiac arrest, death
2 main arrhythmias
bradychardia
tachycardia
what is bradycardia
<60bpm
slow signals from SA node
SINUS BRADYCARDIA
or can be caused by damage to SA node, AV node or conductive tissue
which will block signals
treatment for bradychardia
pacemaker
what is tachycardia
> 100bpm
2 type:
> sinus tachycardia
(normal PQRST wave, but quicker)
caused by: drugs, hormones(e.g. thyroid)
> non-sinus tachycardia
= additional abmornal impulses in ECG
some types of arrythmia
atrial fibrilation (AF)
long QT syndrome (LQTS)
Ventricular tachcardia(VT)
Ventricular fibrilation (VF)
what is atrial fibrilation (AF)
most common
- rapid impulses
- so it quivers but doesnt quite contract
- can go undetected
- cause palpitations, fatining
- increases risk of stroke (due to the statis in blood flow cuz less contraction)
what is long QT syndrome
prolongs the QT interval
affects mostly young people under 25
caused by genetic channelopathies (leading to prolonged action potential)
can cause additional ventricular depolarisations
can lead to ventricular tachycardia
what is ventricular tachycardia
early depolarisation
leads to premature ventricul contraction
and not adequate filling before the heart contracts
prolonged VT can lead to ventricular fibrilation
what is ventricular fibrilation
ie cardiac arrest
ventricles dont pump
w/o treament - death
