Ischaemic Heart Disease Flashcards
What condition does a sharp pain in the chest usually associate with?
Pericarditis
What type of pain typically evolves during myocardial ischaemia?
Tightening pain
What pain is likely to be felt during aortic dissection?
Tearing
What condition can be associated with MI and no pain?
Diabetes.
What is myocardial ischaemia?
This is where blood supply is not sufficient to meet O2 demand.
Which cells of the heart are at highest risk of ischaemia?
Endocardial cells as blood flow is from epi to endocardium so these are at the end of the arteries.
What type of heart beat worsens ischaemia and why?
Tachycardia worsens ischaemia because the arteries fill during diastole and this is shortened when the heart is beating faster.
What is the most common cause of myocardial ischaemia?
Atherosclerosis, a fixed narrowing of the blood vessel. These are particularly problematic in the heart due to the lack of collaterals.
What factors affecting supply to myocardium can cause ischaemia?
Wall tension - preload vs afterload, heart rate and contractility.
What factors associated with demand can cause coronary ischaemia?
The o2 carrying capacity of the blood, coronary artery resistance, perfusion pressure.
Name non-modifiable risk factors for coronary artery disease.
Age, gender, family history.
What risk factors for coronary artery disease are modifiable?
Diet, high Cholestrol, smoking, hypertension, diabetes mellitus, obesity, lack of exercise, psychological factors, low fruit and veg intake.
What is an atheromatous plaque?
This has a necrotic centre and a fibrous cap
Describe the appearance of a vulnerable atheromatous plaque.
This will have a large necrotic centre and a thin fibrous cap. it is therefore more likely to fissure.
What is fissuring?
This is when an atheromatous plaque breaks through into the lumen of the blood vessel, leaving a rough surface which leads to thrombus formation.
What happens if a thrombus either partially of fully blocks the coronary blood vessel?
partial blockage leads to NSTEMI, full blockage leads to STEMI
What is stable angina?
This is when there is a stable plaque, and no symptoms at rest but on exertion, typical pain precipitates due to ischaemia. This is relieved on rest.
What changes might be seen on an exercise ECG for a patient with stable angina?
ST depression due to sub-endocardial ischaemia.
What drugs might be used long term to treat stable angina?
Ca channel blockers, beta blockers, long acting nitrates, statins or aspirin. These all help to reduce the workload of the heart or the risk of thrombus formation.
What is an angioplasty?
This is opening of a blood vessel and is usually followed by stenting to keep the lumen open.
What vessels are used for coronary artery grafts?
Internal mammary artery, radial artery and saphenous vein.
What conditions are included in acute coronary syndrome?
Unstable angina and acute myocardial infarction.
What are all acute coronary syndromes caused by?
These are all caused by fissuring of an atheromatous plaque into the lumen and subsequent thrombus formation.
What happens in a STEMI?
In STEMI, there is a transmural (full thickness) infarction, and this leads to ST elevation in the leads facing the affected area.
How can we distinguish between unstable angina and NSTEMI?
In unstable angina, there are no blood markers for necrosis.
What ECG changes are seen in NSTEMI and unstable angina?
There can be ST depression, T inversion or normal.
Why is injury limited to sub-endocardial areas in NSTEMI?
There is some collateral circulation present and only partial occlusion of the artery.
How can worsening angina present?
In some cases it shows a slow, gradual progression and includes pain at rest, however in other cases it presents like an acute MI.
What biochemical marker is used for NSTEMI/STEMI?
Troponin I or T.
In acute MI, what will not relieve symptoms?
Rest or nitrates.
How will a patient having an MI present?
They will be anxious or distressed and they will be sweating, have pallor, cold and clammy.
In acute MI, comment on the heart rate and blood pressure.
The patient is likely to be Tachycardic, with a low BP.
Name three ECG changes seen in a STEMI.
Pathological Q waves, T inversion and ST segment elevation.
What is CK-MB?
This is the heart isoenzymes for creatinine kinase and is present in the blood 3-8 hours after MI till around 48-72 hours.
When is creatinine kinase of significance?
In patients who have had Mi in last 10 days, troponin will still be raised so we can test for creatinine kinase instead.
How is a STEMI treated?
Urgent PCI is needed. If not available, then fibrinolysis.
What type of treatment is given to people with partial coronary artery occlusion?
Antithrombotic therapy to prevent formation of an excessive thrombus.
What is anti-ischaemic therapy?
This reduces workload of the heart to prevent ischaemia and includes nitrates and B blockers.
Why is aspirin given in acute coronary syndrome treatment?
It is anti-platelet and so reduces the number of platelets and therefore clot formation.
Name some long term treatments which might be started after an MI.
Aspirin, ace inhibitors, statins, b blockers
What complication of MI can cause sudden cardiac death?
Ventricular fibrillation
What complications of MI can occur?
Arrhythmias, heart failure and cardiogenic shock.
