Acute Coronary Disease Flashcards
Define ACD
Any sudden cardiac event suspected or proven to be related to a problem with the coronary arteries.
The problems associated with ACD are due to myocardial ischaemia
What is this?
reduced blood flow and hence O2 to the myocardium through the coronary arteries.
Describe a major MI
due to a complete coronary artery occlusion (STEMI) which causes full thickness damage to the myocardium.
- ST elevation MI = STEMI
- Q wave MI - if left untreated at 3 days
- Transmural MI
Describe a minor MI
due to a partial coronary occlusion (NSTEMI) which causes partial thickness damage just under the endocardium.
- non ST elevation = NSTEMI
- no Q wave
- subendocardial MI
What is the difference between chronic coronary disease and acute coronary disease?
Chronic - has a thick fibrous cap so the plaque is less likely to rupture (stable angina)
Acute - has a thin fibrous cap so is more likely to rupture and therefore cause a thrombosis. (unstable angina)
How would you be able to detect cardiac cell death?
-positive cardiac biomarkers (blood test- troponin)
- symptoms of ischaemia (SOB, chest pain)
- new ECG changes
- evidence of coronary problem on coronary angiogram or autopsy
- evidence of new cardiac damage on another test
Other than the breakdown of myocardium, what are the other ways that troponin can increase in the blood?
Pulmonary embolism
Sepsis
Renal failure
Sub arachnoid haemorrhage
Describe the five types of MI 1. 2. 3. 4a. 4b. 5.
1. spontaneous ischaemia associated with plaque rupture/erosion/fissuring causes: -atheroscelosis -coronary vasospasm (cocaine) -coronary tear (common in young females) -embolism down coronary artery -inflammation of the coronary arteries -radiotherapy causing stenosis and fibrosis
- imbalance of supply and demand of oxygen
- hypertrophy - sudden cardiac death with symptoms of ischaemia accompanied with a ST elevation. (complete occlusion)
4a. associated with percutaneous coronary intervention (stenting) with an increase of three fold of normal troponin levels.
4b. associated with verified stent thrombosis via angiography or autopsy. - Associated with CABG.
On an ECG, which coronary arteries would cause a
lateral MI
anterior MI
inferior MI
Lateral = circumflex artery Anterior = LAD artery Inferior = right coronary artery
A posterior MI can be easily missed as there are no leads on the back of the patient measuring the heart activity.
Posterior wall is usually supplied by the RCA so inferior changes may also be noted.
Can be supplied by LCx
When should leads be put on the posterior of a patient?
If
ECG is normal
patient looks very unwell, sweaty, chest pain
Risk factors for a MI
¥ Male ¥ Age ¥ Known heart disease ¥ High blood pressure ¥ High cholesterol ¥ Diabetes ¥ Smoker ¥ Family history of premature heart disease
What is the treatment for a STEMI?
Reperfusion treatment
- mechanical (PCI) - in a cath lab
- medication (thrombolysis) - dissolves clot, potent blood thinner
What are the contradictions of thrombolysis?
Stroke, previous bleed, recent operations, if on warfarin or aspirin, severe hypertension.
What are the common NSTEMI patients with an elevated troponin level?
¥ older
¥ more likely to have previous MI
¥ more likely to have previous CABG/PCI
¥ may not have clear, obvious presentation
How do you manage a suspected ACS?
admit to hospital
monitor cardiac activity
