265 - cardiac Flashcards
what is CHD also known as?
coronary heart disease aka IHD (ischaemic heart disease) or coronary artery disease (CAD)
what are the two major clinical forms of CHD?
AMI and angina
what is the main cause of CHD?
atherosclerosis
describe blood supply to the heart
left and right coronary arteries supply each side
left branches into the circumflex artery and the left anterior descending (LAD) artery
difference between ischaemia and hypoxia?
ischaemia - lack of blood flow
hypoxia - lack of oxygen
pathogenesis of atherosclerosis
damage to endothelium of blood vessels (chronic) →
development of a fatty streak →
fibrous plaque forms resulting in narrowing of lumen
risk factors for chronic endothelial injury which can lead to athersclerosis?
hypertension smoking hyperlipidaemia diabetes infections toxins
what is acute coronary syndrome?
unstable angina and MI - the more serious manifestations of CAD
most common type of cardiovascular disease?
CHD (CAD)
what type of disease is coronary artery disease?
Coronary artery disease is a type of blood vessel disorder that is included in the general category of atherosclerosis
mortality rate for MI?
decreasing, but remains the leading cause of death from all cardiovascular diseases and death in general
most common cause of ischaemia?
atherosclerosis
difference between atherosclerosis and arteriosclerosis?
Arteriosclerosis is the stiffening or hardening of the artery walls.
Atherosclerosis is the narrowing of the artery because of plaque build-up.
Atherosclerosis is a specific type of arteriosclerosis.
define myocardial ischaemia?
imbalance between oxygen supply and demand to the heart tissue
narrowing of a major coronary artery by > 50% → ischaemia, especially during
exercise
how quickly do cardiac cells form lactic acid after an occulsion? for how long are cardiac cells viable after occlusion?
after 10 seconds of anaerobic respiration
cells are viable for 20 mins, then infarct will occur
signs and symptoms of MI?
severe pain chest discomfort - heaviness, pressure pain may radiate to left arm, neck pallor and diaphoresis dyspnoea may occur
most common drug used to treat angina?
nitrates - anginine, GTN
aim of anti-anginal drugs?
reduction of cardiac workload
adverse effects of nitrates?
hypotension
fainting
flushing
headache
MOA of nitrates?
metabolised to nitric oxide in vessel walls → causes vasodilation of blood vessels → decreases preload and afterload → decreases SV →decreases cardiac output →decreases O2 demands → reduced cardiac workload
nitrates: routes of administration?
sublingual, IV, nasal spray
management options for AMI?
angioplasty, anticoagulants
what is an AMI?
irreversible myocardial cell death (necrosis) as a result of sustained ischaemia >20 minutes
most common cause of AMI?
secondary to thrombus in 80%-90% of cases
how long does the necrosis of the entire thickness of the myocardium take?
4-6 hours
what is AF?
disorganization of atrial electrical activity due to multiple ectopic foci where the P waves are replaced by chaotic, fibrillatory waves
