Ischaemic heart disease Flashcards
What is the mat common cause for ischaemia
Coronary atheroma
Non modifiable risk factors for coronary atheroma
Age increasing
Sex male
Family history, genetics, ethnicity.
Modifiable risk factors for coronary atheroma
Hyperlipidaemia
Hypertension
Diabetes
Smoking
When does coronary flow occur
During diastole
Which direction does coronary flow occur
From the epicardium to endocardium
Describe the process of coronary atheroma
Atheroma tours plaque with necrotic centre and fibrous cap can build up in coronary vessels.
Lumen occluded
What is a stable plaque
Small necrotic core
Large fibrous cap
Less likely to rupture
What is a vulnerable plaque
Large necrotic core
Thin fibrous cap
More likely to rupture
What happens when a plaque fissures
Blood is exposed to thrombogenic material in necrotic core causing a platelet clot in the blood followed by a fibrin thrombus.
This may totally occlude the artery
Site of ischaemic chest pain
Central
Retrosternal
Left sided
Where does ischaemic chest pain radiate
Shoulders, arms on the left side
Neck, jaw, epigastrium, back
Quality of ischaemic chest pain
Tightening, heavy, crushing, pressure
What is stable angina
Atheromatous plaque occlude>70%
Moderate reduction in blood flow, but sufficient at rest.
Ischaemia during high activity
No monocyte injury or necrosis
When does stable angina chest pain occur
Brief episodes through exertion, emotional stress, after meals, cold
How is angina treated
Nitrate spray (venodilator) Calcium channel blockers Beta blockers Aspirin Statins Revascularisation
How does aspirin work
Blocks platelets from making thromboxane a2
This activates platelet aggregation
Thus platelet aggregation is inhibited
Reduced thrombus formation
How do statins act
Lower cholesterol production, reducing progression of atherosclerosis
Increase plaque stability
What is unstable angina
Ischaemic chest pain that occurs at rest.
Severe pain with crescendo pattern
What is diagnosis of angina based on
History
Exercise stress test
What is the exercise stress test
Graded exercise on a treadmill until Target heart rate is reached Chest pain occurs ECG changes Other problem
ECG changes in exercise stress test
ST depression
History of MI
Central crushing chest pain Radiates to shoulder arm jaw back Severe pain at rest No precipitant Not relieved by nitrate or rest Sympathetic signs Sweating palor tachycardia cold clammy skin
Describe occlusion by thrombus, myocardial necrosis, ECG and biomarkers in unstable angina
Occlusion is partial
No necrosis
ST depression, T wave inversion or normal
No biomarkers
Describe occlusion by thrombus, myocardial necrosis, ECG and biomarkers in NSTEMI
Partial occlusion
Some necrosis
No ST elevation
Troponin
