acute coronary syndromes Flashcards
what happens when a b.v narrows?
inadequate O2 delivery for tissue needs
cramp in affected tissue/muscle
no residual deficit at first
what happens when a b.v is occluded?
no O2 delivery - tissue death
severe pain
loss of function of muscle
what are acute coronary syndromes?
acute ischaemic events affecting the heart
describe stable angina
increased demand due to atherosclerotic plaque
vessel unable to dilate enough for adequate blood flow
prompted by exercise
normal ECG
normal troponins
describe unstable angina
plaque ruptures and thrombus forms around ruptured plaque causing partial occlusion of vessel
occurs at rest
normal troponins
describe NSTEMI
plaque rupture thrombus formation causes partial occlusion to vessel that results in injury and infarct to subendocardial myocardium
elevated troponins
describe STEMI
ST elevation
complete occlusion of b.v lumen resulting in transmural injury and infarct to the myocardium
elevated troponin
how is ACS diagnosed?
history
ECG findings
biomarkers -troponin
what are the symptoms of stable angina?
no pain at rest pain w/ certain level of exertion -worse w/ cold weather/emotion pain relieved by rest px lives w/i limits of tolerance gradual deterioration
what is hyperdynamic circulation?
anaemia
hyperthyroidism
hypovolaemia
what investigations are used for angina?
ECG -rest/exercise eliminate other disease angiography echocardiography isotope studies
what is an exercise ECG?
tests ischaemia of the heart in real time
allows changes to be seen and stopped at reversible stage
how is angina treated?
reduce O2 demands of heart -reduce afterload (BP) -reduce preload -correct mechanical issues increase O2 delivery to tissues -dilate blocked/narrowed vessels - angioplasty -bypass blocked/narrowed vessels CABG
what are the non-drug therapies for angina?
explanation of illness -live w/i limitations -adequate for someone with limited activity/mobility modify risk factors -stop smoking -exercise program -improve diet/ control cholesterol
what is the drug therapy available for angina?
to reduce MI risk -aspirin hypertension -diuretics, Ca channel antagonists -ace inhibitors, B blockers reduce heart filling pressure/ dilate coronary vessels -nitrates -short/long actine emergency GTN spray -short shelf life -reduces preload -sublingual
what is the surgical therapy for angina?
CABG -benefit not always obtained -major surgery -10 year benefit angioplasty & stenting -lower risk but lower benefit -risk of vessel rupture during procedure -percutaneous intervention (PCI)
what is peripheral vascular disease?
angina of the tissues -usually lower limb -artheroma in femoral/popliteal vessels claudication pain in limb on exercise -claudication distance -pain relieved with rest managed same as angina
what are some consequences of PVD?
limitation of function
poor wound healing
may lead to tissue necrosis & gangrene
aggravated by CV risk factors
how does ischaemia progress to infaction?
atheroma in vessels
-ulcerated plaques with platelet aggregates
-thrombosis on the surface
thrombosis can enlarge rapidly to block vessel
plaque surface/platelets detach
-travel downstream and block vessels
-no blood flow to that area - infarction
where does infarction occur in:
heart
limb
brain
coronary artery
femoral & popliteal arteries
carotid arteries
what is a myocardial infarction?
result of blocked left anterior descending coronary artery
what is the strategy for infarction?
reduce tissue loss from necrosis -open blood flow to ischaemic tissue -thrombolysis -angioplasty bypass obstruction -CABG, fem/pop bypass
how to prevent a further infarction?
risk factor management
aspirin
what is a stroke?
short duration transient ischaemic attack deficit variable -loss of function -depends on brain region involved -usually some recovery in time
