cardio (+ CNS) Flashcards
(167 cards)
what is the definition of ischaemic heart disease?
what are the two types of aetiology?
generic designation for a group of syndromes resulting from myocardial ischaemia
(an imbalance between demand and supply of oxygenated blood to the heart)
reduced supply (almost always) - norm coronary artery atherosclorosis
increased demand (sometimes) - myocardial hypertrophy
what are the 4 main syndromes which come under the umbrella of ischaemic heart disease (IHD)?
- MI
- angina pectoris
- chronic IHD with heart failure
- sudden cardiac death
what are the 3 different types of angina?
stable angina
unstable angina
prinzmetal (aka variant) angina
- due to vasospasm NOT atherosclerosis
- only about 2% of angina
- occurs in younger people with few/no atherosclerotic risk factors
what are the 3 main clinical differences between stable and unstable angina?
stable:
- pain on exertion/stress
- pain begins slowly and gets worse over minutes
- pain relieved by rest or medication
- nb seems to be a predictable pattern as to the onset and timing of pain
unstable:
- attacks of pain occur randomly, with or without exertion
- pain is sudden + severe
- pain not relieved by rest or medication
nb in prinzmetal/variant angina you tend to pain radomly at rest
nb stable angina can develop into unstable angina
what are the 3 things which make up acute coronary syndrome?
- unstable angina
- MI
- sudden cardiac death
in terms of testing blood levels for cholesterol what is the most useful measuring for predicting risk of IHD?
a high total cholesterol:HDL ratio is BAD
does coronary heart disease affect more men or more women
more men
nb stroke affects more women
what are the three main modifiable risk factors for IHD?
- smoking
- poor diet
- low physical activity
nb alcohol (in moderation) is cardioprotective
describe the pathogenesis of myocardial ischaemia
Myocardial ischemia is a consequence of reduced blood flow in coronary arteries, due to a combination ofFIXED VESSEL NARROWINGandABNORMAL VASCULAR TONEas a result ofATHEROSCLEROSISandENDOTHELIAL DYSFUNCTION. This leads to an imbalance between myocardial oxygen supply and demand
in the pathogenesis of IHD, when does it become chronic IHD?
when more than 75% of the lumen of the coronary artery is occluded
after this level of occlusion the artery can no longer autoregulate and vasodilate + permanent chronic damage can occur = chronic IHD
what is the definition of myocardial infarction?
what are the 2 histological types?
death of cardiac muscle from prolonged ischaemia
subendocardial
- inner one third of wall (least well perfused)
transmural
- full thickness of myocardium
what is the pathophysiology of a stable atherosclerotic plaque leading to an MI?
- acute plaque changes/rupture of fibrous cap
- > platelet aggregation
- > thrombus formation
- > occlusion of coronary artery
- > infarction
histologically what changes are seen in the myocardium: <24hrs post-MI? - 1-2 days post-MI? - 3-4 days post-MI? - 1-3wks post-MI? - 3-6wks post-MI?
<24hrs post-MI:
- normal
1-2 days post-MI:
- pale
- oedema
- myocyte necrosis
- neutrophils
3-4 days post-MI:
- yellow with haemorrhagic edge
- myocyte necrosis
- macrophages
1-3wks post-MI:
- pale
- thin
- granulation tissue then fibrosis
3-6wks post-MI:
- dense fibrous scar
what are the main complications of MI? 7
- arrythmias
- cardiogenic shock
- heart failure
- pericarditis (if infarction occurs in pericardium as well)
- ventricular aneurysm
- cardiac tamponade
- thromboembolism
why can an MI lead to arrythmias?
- either directly or due to limited perfusion to the conduction system structures (SA node etc)
how can an MI lead to heart failure? 2
what are two synonyms for heart failure?
- contractility dysfunction
- papillary muscle infarct -> severe mitral regurgitation
- congestive cardiac failure
- congestive heart failure
what is the definition of cardiogenic shock?
Cardiogenic shock is defined by sustained low blood pressure with tissue hypoperfusion despite adequate left ventricular filling pressure
(so basically there is enough blood but the heart isn’t pumping it so no oxygen/nutrients is getting to tissues)
what is cardiac tamponade?
describe how an MI can cause it?
when fluid builds up in the pericardial sac around the heart + subsequently compresses the heart
full thickness (transmural) MI -> myocardium so weak that it ruptures + blood goes into pericardium + compresses heart from outside
nb cardiac tamponade has lots of acute + chronic causes, not just MI
what are the 5 main blood markers of IHD?
what can they also be raised in?
- troponins T & I
- –also raised in PE, heart failure + myocarditis
- creatine kinase
- – also raised in skeletal muscle and brain damage
- myoglobin
- – also released from damaged skeletal muscle
- lactate dehydrogenase isoenzyme 1
- – can also be raised in liver damage
- aspartate transaminase
- – also present in liver so less useful
what is creatine kinase?
in which 3 places is it specifically found in the body?
what are the 3 isoenzymes?
which is most specific to myocardium?
an enzyme
chiefly found in:
- brain
- skeletal muscles
- myocardium
CK-BB
CK-MM
CK-MB
CK-MB is the one found mainly in myocardium (bit in skeletal muscle as well though!)
what is the arbritary definition of hypertension? systolic + diastolic
a sustained systolic pressure greater than 140mmHg and/or sustained diastolic pressure greater than 90mmHg
what are the main features of metabolic syndrome? 4
what 3 conditions are most commonly caused by metabolic syndrome?
- high BP
- high blood sugar
- excess body fat around the waist
- high/abnormalchlesterol +/or triglyceride levels
- heart disease
- stroke
- diabetes
what are the main modifiable environmental risk factors for primary/essential hypertension? 5
- obesity
- alcohol
- smoking
- stress
- Na+ intake
what % of the UK adult population has high BP?
about 1/3