ischaemic heart disease Flashcards
how do you work out oxygen demand?
blood flow x the difference between arterial and venous O2 concentration
oxygen… ? … dilates coronary arteries?
defficiency
what two things control oxygen demand in the coronary arteries?
contractions and heart rate
what is coronary artery disease characterised by?
transient myocardial ischaemia
give 3 cases of coronary artery disease?
atherosclerosis
embolism
coronary spasm
what is stenosis?
narrowing of the arteries
what is variant angina?
pain at rest due to a spasm
how does ischaemia lead to an increased pressure on the heart and potential acidosis?
when patients have ischaemia, ATP is produced anaerobically, this produces lactic acid which dissociates into lactate and H+, high levels of H+ lead to acidosis and low levels of ATP leads to reduced contraction of cardiac muscle and more pressure build up
what is used to ease angina pain and give a side effect?
1 or 2 sprays of GTN spray, side effect = tachycardia
what is a red flag of GTN use?
if pain remains for more than 5 minutes after using GTN spray, call an ambulance
how does GTN spray ease angina?
the nitrates in GTN spray cause vasodilation allowing more oxygen to the heart
how does LDL cholesterol end up in vessel walls?
LDL binds to the scavenger receptor that mediates the binding of cholesterol to skin and vessel walls
what percentage of cholesterol comes from where?
70% by the liver
30% from the food we eat
explain the process of cholesterol becoming atheromas in blood vessels?
the first sign of cholesterol in blood vessels is fatty streaks, these fatty streaks then develop foam cell lipid deposits within, which then form fibrous plaques and atheromas
what drugs inhibit cholesterol synthesis?
statins
