stable angina and acute coronary syndrome Flashcards
What is chronic stable angina?
- Fixed stenosis of a coronary vessel due to atherosclerosis
- this leads to demand led ischaemia (pain on exertion)
- predictable and safe
How is angina diagnosed?
Clinical diagnosis:
Visceral pain from myocardial hypoxia:
-Hard to describe
-Gestures
(pressing/squeezing/heaviness radiating back/neck/jaw/teeth)
Characteristic patterns of:
- Provocation (exertion/stress/after meals/cold wind)
- Relief (rest/GTN)
- Timing (few mins)
Characteristic background
-Risk factors
If stable angina has been diagnosed what is the drug treatment?
- GTN spray (short acting nitrate), if pain doesn’t settle repeat dose after 5mins, if still doesnt settle call ambulance
- a beta blocker or a calcium channel blocker: reduces heart rate and reduces oxygen demand to the heart (calcium channels blockers also dilate coronary arteries)
- Aspirin: antiplatelet
- ACE inhibitor: antihypertensive
- Statin: reduces cholesterol
- (manage HTN)
When would invasive angiography be considered for stable angina? What has to be taken into consideration?
Invasive angiogrpahy and revascularisation for severe symptoms or high risk
CABG vs PCI should be determined by discussion
Consider: Multi-vessel disease, diffuse or focal Left main disease Diabetes Co-morbidities
What 3 conditions does acute coronoary syndrome encompass?
- unstable angina
- NSTEMI
- STEMI
unstable angina and NSTEMI are also known as non-ST elevation acute coronary syndrome
What is the difference between an NSTEMI and STEMI
- no difference clinically
- no ST elevation on ECG for NSTEMI
- NSTEMI is the partial occlusion of a major coronary artery or a complete occlusion of a minor coronary artery = partial thickness myocardial ischaemia
- STEMI is the complete occlusion of a major coronary artery = full thickness myocardial ischaemia
- in an NSTEMI cardiac markers are less elevated
- Primary PCI is the treatment for STEMI
- angiography with a view to revascularisation is the treatment for NSTEMI (and unstable angina)
What is the pathological change that causes stable angina to progress to acute coronary syndrome?
The plaque ruptures or fissures which causes thrombosis superimposed on atherosclerosis = occlusion of vessel
For acute coronary syndrome what are the clinical features?
-Severe crushing central chest pain
•Radiating to jaw and arms, especially the
left
- Similar to angina but more severe, prolonged and not relieved by GTN
- Associated with sweating nausea and often vomiting
What is the diagnosis of STEMI on ECG?
•>1mm ST elevation in 2 adjacent limb
leads
- > 2mm ST elevation in at least 2 contiguous precordial leads
- New onset bundle branch block
(also see t wave inversion and Q waves - first day)
What are the ECG territories for the right coronary artery? is this an inferior/anterior/septal MI?
leads 2, 3 and AVF
inferior MI
What are the ECG territories for the left anterior descending coronary artery? is this an inferior/anterior/septal MI?
V1-V4
Anterior/septal MI
What are the ECG territories for the left circumflex coronary artery? is this an inferior/anterior/septal MI?
V5, V6, 1, AVL
Lateral MI
What cardiac enzymes and protein markers are used to help diagnose acute coronary syndrome? what are the downfalls of this?
May be normal at presentation
May not have time to wait for results in STEMI
Enzyme: Creatinine kinase (CK)
- peaks at 24hrs
- also in skeletal muscle and brain
Protein marker: Troponin (Tn)
-highly specific for cardiac muscle damage
What is the treatment for acute coronary syndrome?
M - morphine (10mg in 10ml titrate) (+antiemetic IV)
O - oxygen (high flow)
N - nitrates (Sublingual GTN 2 sprays if BP> 90mmHg)
A - aspirin (300mg PO loading dose then 75mg OD)
+C - clopidogrel (300-600mg PO loading dose then 75mg OD)
What are the indications for reperfusion therapy (thrombolysis or PCI) for acute coronary syndrome?
- Chest pain suggestive of acute myocardial infarction
More than 20 minutes less than 12 hours - ECG changes
acute ST elevation
NEW left bundle branch block (LBBB) - No contraindications (if they present aftter 12 hours after thrombolysis it is not indicated)
When do patients recieve thrombolysis
- if they are unlikely to receive PCI within 90mins
- then they are taken to specialist intervention centre for urgent coronary angiography or emergency rescue angioplasty
What are the three risks of thrombolytic therapy?
Failure to re-perfuse
Haemorrhage
–Minor
–Major
–Intracranial haemorrhage 0.5 –2.0%
Hypersensitivity
What are the 4 general complications of acute MI?
- Death
- Arrythmic complications
- structural complications
- functional complications
What are 8 structural complications of an acute MI
Cardiac rupture
Ventricular septal defect
Mitral valve regurgitation
Left ventricular aneurysm formation
Mural thrombus +/- systemic emboli
Inflammation
Acute pericarditis
Dressler’s syndrome
what is dressler’s syndrome?
Pericarditis that develops 2-10weeks post-MI/heart surgery
-a low grade fever
-chest pain
-Pericardial friction rub
rarely, the pericardial effusion may cause cardiac tamponade
What 3 functional complications are assoc. with acute MI?
Acute ventricular failure
–left
–right
– both (biventricular failure)
Chronic cardiac failure
Cardiogenic shock
What is the KILLIP classification?
a measure of in-hospital mortality:
I - No signs of heart failure 6%
II - Crepitations < 50% of lung fields 17%
III- Crepitations > 50% of lung fields 38%
IV- Cardiogenic shock 81%
when would patients with non-ST elevation acute coronary syndrome be considered for invasive angiography?
-those at medium or high risk of early recurrent cardiovascular events should undergo early coronary angriography and revascularisation
What are the four phases of cardiac rehabilitation?
Phase 1 in-patient (day 1 CCU, Day 2-3 step down unit, Day 3-6 ward, Day 4-6 discharge)
Phase 2 early post discharge period
Phase 3 structured exercise
programme – usually hospital based
Phase 4 long term maintenance of
physical activity and lifestyle change
– usually community base
What are the 6 targets for patients post-MI?
Avoid smoking
Healthy diet
Regular aerobic exercise
Optimal drug therapy
Cholesterol < 4.0 mmol/l
BP:
- < 140/ 85 mmHg
- Diabetes, renal disease, target organ damage <130/80 mmHg
What drug therapy is offered to everyone who has had an MI?
- ACE inhibitor
- dual antiplatelet therapy (aspirin plus a second antiplatelet agent)
- beta-blocker
- statin
What is added for those who have had an MI and also have heart failure?
Spironalactone