Acute coronary syndromes. Flashcards
What do we tell someone with angina to do to keep themselves safe?
Stop, sit and spray.
What is an acute coronary syndrome? What does it cause?
Acute presentation of any coronary artery disease including unstable angina and evolving MI. Both have a common underlying pathology.
It is a dynamic stenosis causing either subtotal or complete occlusion.
Causes demand led ischaemia.
Also includes sudden death.
What is angina brought on by?
Exercise, cold, emotions, heavy meals.
What is angina relieved by?
Rest and GTN.
What are the symptoms of angina?
Chest pain that may radiate.
What two types of angina do we have and what are they?
Stable - exercise exacerbated, relieved by rest.
Unstable - increasing severity and frequency. Happens at exercise or at rest and gives a great,y increased chance of MI.
What two types of MI are there and what are the differences on ECG?
STEMI - ST elevation. QRS doesn’t come back to baseline.
NSTEMI - without ST elevation. May have no electrical disturbance and so a normal ECG. Could also have a depressed or Inverted ST.
What treatment does a STEMI require and what is the time scale?
PCI - door to needle time 90 mins.
What symptoms do we get with a fatty streak?
Clinically silent.
What syndromes do we get with atherosclerosis plaques and fibrous plaques of the coronary arteries?
Angina.
What symptoms do we get with plaque rupture fissure and thrombi of coronary arteries?
Acute coronary syndromes.
What factors can affect coronary plaque rupture and fissuring?
Sudden changes in intraluminal pressure of tone.
Bending and twisting of an artery during each heart contraction.
Lipid content of plaque.
Thickening of fibrous cap.
Plaque shape.
Mechanical injury.
What is the central pathway of platelet activation?
Initiation –> Activation –> activator release, aggregation and inflammation –> vascular blockage –> acute MI, stroke or death.
How can the platelet cascade activation be stopped?
By effective management of platelet activation over time.
What can an MI lead to in 25% of people?
Heart failure.
Where does an MI radiate in a lot of patients?
Especially the left arm. Also jaw and right arm.
What type of pain do we get with cardiac chest pain?
Gripping, squeezing, heavy and crushing.
What are the steps in management of angina?
Modify risk factors.
Aspirin.
Beta blockers.
Nitrates.
Possibly long acting calcium antagonist, especially if there is a contraindication to beta blockers.
Potassium channel activator if it’s still not controlled.
What are the duration differences between MI and angina?
Angina 10 mins vs MI 30 mins or longer.
What are the onset differences between MI and angina?
Angina at exertion and MI at rest.
What are the severity differences between MI and angina?
Angina - usual pain.
MI - more severe.
What are the associated symptom differences between MI and angina?
Angina - usually none.
MI - nausea vomiting and sweating.
What do we see on an ECG for angina?
May be normal or may show ST depression or inverted T waves from a past MI.
What else can we do if an angina ECG is normal?
Consider an exercise ECG.
At what time in an MI do we see ST elevation?
First few hours.
At what time in an MI do we see Q wave formation and T wave inversion?
The first day.
At what time in an MI do we see Q waves +- inverted T waves?
With an old MI.
What must we see on an ECG in order to diagnose a STEMI?
Greater or equal to 1mm ST elevation in 2 adjacent limb leads. Or at least 2mm in at least 2 contiguous precordial leads. Or new onset bundle branch block.
What blood tests do we do for MI?
FBC, U and E, glucose and lipids.
Cardiac enzymes.
Myoglobin.
When do we see myoglobin in blood tests for MI, what does it mean?
Rise within 1-4 hours of onset of chest pain.
It is sensitive but not specific.
What is our differential for an MI?
Angina, myocarditis, aortic dissection, PE and oesophageal reflux/spasm.
What might cardiac enzymes be like on presentation and what does this mean for our diagnosis?
May be normal initially and we may not have time to wait for them and must diagnose before this.
What two cardiac enzymes are we interested in?
CK - creatinine Kinase.
TnT- troponin T.
Where do we find creatinine kinase and what times do we find it in blood post MI?
Heart, skeletal muscle and brain.
Peaks within 24 hours.
Why do we use at TnT as a marker for MI?
It is highly specific for cardiac muscle damage. Can detect tiny amounts of myocardial necrosis. It is a marker for cardiac damage.
What else can TnT be raised in other than MI?
PE, sepsis, renal failure, CCF, hypertensive crisis, stroke TIA, pericarditis, myocarditis or post arrhythmia.
What do patients with chest pain and a raised troponin get?
ECG.
What early treatment of an MI do we give?
MONAC. DiaMorphine etc. with antiemetic. IV. Oxygen if hypoxic. Nitrates if BP over 90 mmHg. Aspirin 300mg chewable or oral dispersible. Clopidogrel 300mg.
Thrombolysis if PCI is not available in 90 mins.
What are side effects of GTN?
1 in 10 get a headache.
Drops BP.
GTN syncope.
How long can aspirin and clopidogrel be continued in patients ST elevation acute coronary syndromes?
Up to 4 weeks.