Cardiovascular disease 1 Flashcards
What is ischaemic heart disease?
Inadequate blood supply to the myocardium
What are the causes of ischaemic heart disease?
reduced coronary blood flow, usually atheroma +/- thrombus
myocardial hypertrophy, usually due to systemic hypertension
Any imbalance in supply vs demand
What is the pathogenesis of ischaemic heart disease?
Acute and/or chronic ischaemia
Autoregulation of coronary blood flow breaks down if > 75% occlusion
>90% stenosis may be insufficient at rest
Low diastolic flow especially sub-endocardial
Active aerobic metabolism of cardiac muscle-60 secs of ischaemia before function lost
Myocyte dysfunction/death from ischaemia
Damage is reversible in 20-30 mins
What are the features of angina pectoris?
typical/stable- fixed obstruction, predictable relationship to exertion
variant/Prinzmetal-coronary artery spasm
crescendo/unstable- often due to plaque disruption
What are the features of acute coronary syndrome?
acute myocardial infarction (+/- ECG ST elevation)
crescendo/unstable angina
What is subendocardial myocardial infarction?
The subendocardial myocardium is relatively poorly perfused under normal conditions
If there is
stable atheromanous occlusion of the coronary circulation
an acute hypotensive episode
Then the subendocardial myocardium can infarct without any acute coronary occlusion
What would the morphology of MI be like at
macro - normal/dark
micro - necrosis and neutrophils
What would the morphology of MI be like at 1-2 days?
macro - yellow infarct centre
micro - More necrosis and neutrophils
What would the morphology of MI be like at 3-7 days?
macro - Hyperaemic border, yellow centre
micro - macrophages
What would the morphology of MI be like at 1-3 weeks?
macro - red/grey
micro - granulation tissue
What would the morphology of MI be like at 3-6 weeks?
macro - scar
micro - collagen scar
Describe how cardiac myocyte damage affects troponins T and I?
detectable 2 – 3h, peaks at 12h, detectable to 7 days
raised post MI but also in pulmonary embolism, heart failure, & myocarditis.
Describe how cardiac myocyte damage affects creatine kinase?
detectable 2 – 3h, peaks at 10-24h, detectable to 3 days
Describe how cardiac myocyte damage affects myoglobin?
peak at 2h but also released from damaged skeletal muscle
Describe how cardiac myocyte damage affects Lactate dehydrogenase isoenzyme 1?
peaks at 3days, detectable to 14days
Describe how cardiac myocyte damage affects Aspartate transaminase?
Also present in liver so less useful as a marker of myocardial damage