Acute Coronary Syndrome Flashcards
What is the definition of Acute Coronary Syndrome
A term used for any condition caused by sudden reduced blood flow to the heart
What are the different types of ACS
Unstable angina - pain without an enzyme rise (so no evidence of necrosis)
NSTEMI - chest pain with positive markers of necrosis (ie. troponin) but no ST elevation
STEMI - chest pain with ST elevation on ECG
What does the ST segment on an ECG correspond to
The interval between ventricular depolarization and repolarization
What does ST elevation on an ECG indicate
Full-thickness ischaemia
Usually due to thrombosis of an unstable plaque in a coronary artery causing total occlusion
What does ST depression or T wave abnormalities on an ECG indicate
Subtotal or transient occlusion (ie. NSTEMI)
Where is the ST elevation in an anterior MI
ST elevation in leads V1-4
What artery is occluded in an anterior MI
Left anterior descending artery
Where is the ST elevation in an inferior MI
ST elevation in leads II, III, aVF
What artery is occluded in an inferior MI
Right coronary artery or circumflex coronary artery
Where is the ST elevation in a lateral MI
ST elevation in leads V4-6
What artery is occluded in a lateral MI
Circumflex coronary artery
What ECG changes would you expect in a posterior MI
Prominent R wave in V1 and V2 with ST depression
Mirror image of anterior MI
*Flip ECG upside down and look through the back of the paper
What artery is occluded in a posterior MI
Right coronary artery or circumflex coronary artery
Where is the ST elevation in an anterolateral MI
ST elevation in leads V1-6
What artery is occluded in an anterolateral MI
Proximal left anterior descending artery
What is troponin
Proteins that form part of the myocardial cell structure
Release into the bloodstream indicates myocardial cell damage
How long does it take troponin levels to rise after onset of MI
6-14 hrs
How long do the troponin level stay elevated after an MI
Up to 14 days
When does CK-MB begin to rise after an MI
At least 4 hrs
How long does CK-MB stay elevated for after MI
Falls within 72 hrs
Why should you request an FBC after an MI
Anaemia may precipitate an acute MI in a patient with angina
When should you measure serum cholesterol after an MI
Within 24 hrs or 2 months after
Cholesterol levels drop to artifical low 24hrs after MI
What is the acute management of acute MI
Oxygen sats maintained over 94% with supplemental oxygen
Aspirin - 300mg orally immediately
Glyceryl trinitrate immediately
Morphine - 2-4 mg IV every 5-15 mins with 10mg metoclopramide
What is the time window for the benefit of reperfusion post-MI
Greatest benefit within 3hrs
Little benefit after 12 hrs
What are the option for reperfusion following an MI
Coronary angioplasty
Thrombolysis (with recombinant tissue plasminogen activator) - if timely coronary angioplasty not achievable
What are the indications for coronary angioplasty
History of chest pain lasting less than 24hrs
ECG changes (one of):-
ST elevation over 1mmin standard leads or 2 adjacent chest leads
New bundle branch block on ECG
What are the contraindications for coronary angioplasty
History of haemorrhagic cerebrovascular event
History of any CVA event in the last 6 mths
Recent GI bleed
Recent surgery
Pregnancy
What are the complications of MI
Shock
Structural complications causing - acute MR, VSD
Arrhythmias
Heart failure
What medications would a patient be discharged from hospital with following an MI
Aspirin - long term Clopidogrel - at least 1 year Statin ACE-I Beta blocker
