Cardiovascular Pathology 1 Flashcards
what is meant by cardiovascular disease?
It is an umbrella term used to describe all conditions of the heart and blood vessels
it includes congenital and acquired conditions
What is the definition of ischaemic heart disease?
Generic designation for a group of syndromes resulting from myocardial ischaemia
(an imbalance between demand and supply of oxygenated blood to the heart)
What is the aetiology of ischaemic heart disease?
It is almost always caused by coronary artery atherosclerosis
sometimes due to hypertrophy (increased demand)
What are the 4 ischaemic heart disease syndromes?
Myocardial infarction:
- duration and severity of ischaemia causes myocardial death
angina pectoris:
- ischaemia is less severe and does not cause myocardial death
chronic IHD with heart failure
sudden cardiac death
What are the 3 different types of angina pectoris?
Typical angina is known as stable angina
Prinzmetal angina is variant angina and is due to vasospasm, rather than atherosclerosis
unstable angina is crescendo angina
What are the 3 main features of acute coronary syndrome?
- Myocardial infarction
- unstable angina
- sudden cardiac death
these are all IHD syndromes
What is the epidemiology of ischaemic heart disease like?
Prevalence of IHD is highest in northern England and scotland
What are the main medical risk factors for IHD?
- High blood pressure
- lipid profile abnormalities (high blood cholesterol)
- diabetes
What is a good indicator for risk for CVD?
Instead of looking at total cholesterol
high HDL and low TC:HDL ratio are better indicators of risk for CVD
What are the modifiable lifestyle risk factors of IHD?
- Cigarette smoking
- physical inactivity
- poor diet
What is the benefit of IHD therapeutic advances?
what are examples of these treatments?
Therapeutic advances have allowed earlier, more effective and safer treatments
- lipid lowering medicines
- anti-hypertensive medicines
- antiplatelet medicines
- antidiabetic medicines
What is the pathogenesis of ischaemic heart disease?
Myocardial ischaemia is a consequence of reduced blood flow in coronary arteries
this is due to a combination of fixed vessel narrowing and abnormal vascular tone as a result of atherosclerosis and endothelial dysfunction
this leads to an imbalance between myocardial oxygen supply and demand
what causes myocardial infarction?
what are the 2 different types?
Death of cardiac muscle from prolonged ischaemia
transmural - affects the full thickness
subendocardial - affects the inner one third of the wall (least well perfused)
What is involved in the pathophysiology of myocardial infarction?
- Acute platelet changes
- platelet aggregation
- thrombus formation
- occlusion of coronary artery
When there is a coronary artery thrombus, how does the myocardium change in 6 weeks?
< 24 hours:
- myocardium is normal
1-2 days:
- pale, oedema, myocyte necrosis, neutrophils
3-4 days:
- Yellow with haemorrhagic edge
- myocyte necrosis, macrophages
1-3 weeks:
- pale, thin, granulation tissue then fibrosis
3-6 weeks:
- dense fibrous scar
What is shown here?
Coronary artery thrombus leading to myocardium changes
What are the complications of myocardial infarction?
Arrhythmias:
- either directly or by limited perfusion to the conduction system structures (e.g. SA node)
congestive cardiac failure:
- contractility dysfunction or by papillary muscle infarct/severe MR
others:
- thromboembolism
- pericarditis
- ventricular aneurysm
- cardiac tamponade
- cardiogenic shock
what is shown here?
Myocardial rupture
What is shown here?
Haemopericardium
(cardiac tamponade)
What is shown here?
Mural thrombus
what is haemopericardium?
what can it cause?
Blood in the pericardial sac
depending on the volume and rapidity with which it develops, it may cause cardiac tamponade
What is cardiac tamponade?
A clinical syndrome caused by the accumulation of fluid in the pericardial space
this results in reduced ventricular filling and subsequent haemodynamic compromise
what is meant by a mural thrombus?
where do they tend to occur?
They are thrombi that adhere to the wall of a blood vessel
they occur in large vessels such as the heart and aorta
they can restrict blood flow, but usually do not block it entirely
What is shown here?
Ventricular aneurysm
what is a ventricular aneurysm and what condition is it related to?
Ventricular aneurysms are a complication that occurs after a myocardial infarction
it is a bulge or pocketing of the wall or lining of a vessel
it most commonly occurs in the blood vessels at the base of the septum, or within the aorta
What are the main complications of MI?
How do they result from changes in the heart?
Impaired contractility:
- ventricular thrombus leads to stroke (embolism)
- hypotension causes reduced coronary perfusion and increased ischaemia leading to cardiogenic shock
tissue necrosis:
- papillary muscle infarction leads to mitral regurgitation and congestive heart failure
- ventricular wall rupture causes cardiac tamponade
electrical instability:
- arrhytmias
pericardial inflammation:
- pericarditis
what are the 5 different blood markers of ischaemic heart disease?
- Troponins T & I
- creatine kinase MB
- myoglobin
- lactate dehydrogenase isoenzyme 1
- aspartate transaminase
When should troponins T & I be measured?
When are they raised?
They are proteins released by damaged myocytes
detectable after 2-3h, peaks at 12h and detectable to 7 days
raised post MI but also in pulmonary embolism, heart failure & myocarditis
when is creatinine kinase MB detectable?
Detectable after 2-3 hours
peaks at 10-24 hours
detectable for up to 3 days
what conditions is a rise in creatinine kinase associated with?
It is an enzyme found mainly in the brain, skeletal muscles and heart
an elevated level is seen in heart attacks, when the heart muscle is damaged, or in conditions that cause damage to the skeletal muscles or brain
When is myoglobin detectable?
Peaks at 2 hours but is also released from damaged skeletal muscle
when is lactate dehydrogenase isoenzyme 1 detectable?
Peaks at 3 days but is detectable up to 14 days