L16 - drug treatments of cardiovascular disease Flashcards
define atherosclerosis
build up of cholesterol rich plaques in major arteries causing narrowing of these arteries
what are the components of an atherosclerotic plaque
- fibrous cap (SM and connective tissue)
2. lipid core
what is atherogenesis
development of plaques
describe process of atherogenesis
- macrophages penetrate artery walls and stay there taking up lipids - creating fatty streak
- legion grows and grows creating plaque and narrowing artery
how is fatty streak formed in arteries
macrophage penetrates into artery wall and stays there taking up lipids
what is thrombosis
blood clot
what can happen if an atherosclerotic plaque ruptures?
can cause thrombosis leading to MI/stroke
when will symptoms of an atherosclerotic plaque be noticed?
when it narrows the artery - causing angina for example
what type of plaques are prone to ruptures?
those with thin fibrous cap
what is a stable plaque
thick fibrous cap
greatly narrows artery
loss of coronary flow reserve
what is a vulnerable plaque
a plaque that has:
thin fibrous cap
large lipid core
prone to rupturing
can rupture and cause thrombosis
what is angina
temporary chest pain usually during exercise due to less blood flow to coronary arteries
what ways can drugs treat angina?
- decrease cardiac workload and o2 demand
2 increase o2 supply to ischemic zone by dilating arteries
what drugs can treat angina (6)
- organic nitrates - vasodilation
- B blockers - decrease HR & contractility (and o2 demand)
- ivabradine - decreases HR and therefore decreases work and o2 demand
- ranolazine - decreases cardiac stiffness (so decreases workload and o2 demand)
- Ca2+ channel blockers - vasodilators and decrease afterload
- nicorandil - vasodilator
what does ivabradine do
decreases HR and therefore decreases work and o2 demand of heart
treat angina
what does ranolazine do
decreases cardiac stiffness (incorrect contraction) so decreases workload and o2 demand
can treat angina
how do Ca2+ channel lockers treat angina
they decrease afterload and cause vasodilation
so decrease work and o2 demand
how do B blockers treat angina
they decrease HR and contractility
therefore decreasing workload and o2 demand
how does nicorandil treat angina
vasodilator of arteries and veins
decreases preload and afterload
therefore decreases workload and o2 demand
what receptors mediate contractility of heart?
stimulating B1 receptors
in what two ways does decreasing HR help angina?
it decreases workload and o2 demand
also increases blood flow to coronary arteries of LV
how does decreasing HR increase coronary flow to the LV
during contraction the LV compresses bvs in its wall so the LV only gets blood flow during diastole(relaxation)
slowing HR increases the amount of time spent in diastole
how does atherosclerotic plaque cause myocardial infarction
- plaque rupture in coronary artery
- platelet aggregation and coagulation cause thrombosis
- regional ischemia causes progressive cardiac cell death
what are the consequences and treatments of cardiac ischaemia
- ventricular fibrillation - defibrillator
- severe pain and nausea - morphine
- poor contractility then cell death - remove thrombus
what is chronic heart failure
when CO is not sufficient due to poor contractility
symptoms of chronic heart failure
- oedema
- breathlessness
- enlarged but weaker heart
describe process of cardiac remodelling
- stimulus causes fall in CO which activates RAA system and SNS
- these compensate and restore CO
- the stimulus remains so these systems stay activated for prolonged period of time causing cardiac remodelling
what are the aims of drugs used to treat chronic HF
- reduce cardiac remodelling
2. treat symptoms
what drugs can reduce cardiac remodelling?
- ACE inhibitors (inhibit production of angiotensin2)
- B1 blockers (decreases SNS stimulation)
- aldosterone antagonists
why are aldosterone antagonists used as treatment for CHF
aldosterone leads to increased connective tissue in heart which lowers contractility
inhibiting this will help contractility
what can treat acute HF
B1 agonist
what lifestyle changes can decrease hypertension
lose weight
eat less Na+
exercise
less stress
what are the two things thought to be the main cause on hypertension
- RAA system as it causes water retention
2. SNS overactivity as it causes vasoconstriction
what drugs are used to treat hypertension
vasodilators
diuretics
ACE inhibitors (RAA system)
what are statins and what do they do
statins that reduce cholesterol levels by decreasing synthesis of cholesterol in liver
