29. Acute Myocardial Infarction Flashcards
What are the diagnostic criteria for MI?
Rise and/or fall of blood troponin with at least 1 value >99th percentile of URL, plus at least one of the following:
Ischemia symptoms (e.g. chest pain)
New ST segment or T wave changes or new left bundle branch block on ECG
Development of pathological Q waves on ECG, loss of viable myocardium/wall abnormality, intracoronary thrombus
NB: cardiac myocyte starts to leak intracellular content when ischemic = troponin
Distinguish between unstable angina/NSTEMI and STEMI. Comment on ECGs.
How many types of AMI are there, and what is the main type?
NSTEMI: ruptured coronary plaque with subocclusive thrombus. ECG non diagnostic.
STEMI: ruptured coronary plaque with occlusive thrombus. ECG diagnostic (STE in II, III and aVF)
I, 2, 3, 4a, 4b, 5, Type 1 = spontaneous AMI - plaque rupture = most common
Comment on this ECG. What could have caused it?
AMI = STE: II, III, aVF. Blocked RCA.
What are the clinical manifestations of AMI:
a) If ischaemic myocardial injury?
a) of autonomic disturbance?
Why do 33% of people who die from AMI do so before they reach hospital?
a) Chest pain, 4th heart sound due to v. still ventricle, low grade fever, leucocoytosis and raised inflammatory markers (ESR, CRP), troponin leak
b) tachycardia (sympathetic), sweating and vomiting (vagal)
Ventricular fibrillation - need to be defibrillated
What can you see in this CXR?
What is this caused in congestive heart failure?
Pulmonary oedema. Bat wings (bilateral perihilar shadowin due to fluid accumulation)
Heart unable to pump blood efficiently, blood can back up into veins that take blood through lungs. As pressure in these BV increases. fluid is pushed into alveoli in lungs, reducing normal O2 movement.
How is infarct size in STEMI reduced in hospital with medications? What is this called?
Streptokinase (thrombolytic medication) and asprin (antiplatelet drug) given. Reperfusion therapy.
How is STEMI treated?
Take pt straight to cath lab. Give aspirin + ticagrelor (antiplatelet), heparin (blood thinner), PPCI (primary percutaneous coronary intervention) = treats stenosis of coronary arteries, accesses blood through femoral/radial artery, perform coronary angioplasty: stenting to reopen artery.
Better result with this than thrombolysis.
How is NSTEMI treated in emergency?
Is NSTEMI or STEMI worse?
Asprin and ticagrelor, +/- GP IIb/IIIa inhibitor, Fondaparinux (factor Xa inhibitor), Anti-ischaemic drugs (BB, nitrates), Angiography +/- PCI within 24-96hrs.
NSTEMI, probably becasue older people = comorbidities
What can you see in this before and after angiogram?
RCA almost occluded before. After = stented
Secondary prevention is important for saving lives after discharge. List some methods concerning:
a) lifestyle
b) drugs
c) devices
a) smoking, diet, exercise
* NB: smokers who quit reduce risk of major adverse cardiac events by 40%*
b) aspirin, ticagrelor, statin, beta-blocker, ACE-I (treatment for life except ticagrelor)
c) ICD - pacemaker that detects ventricular arythmias and gives a shock
List 3 situations where you would give a post AMI patient an implantable defibrillator?
1) cardiac arrest VT/VF >24h after onset of AMI
2. sustained VT with syncope >24hrs after onset of AMI
3. LV ejection fraction <35%
List 3 life saving strategies in AMI to prevent:
a) pre-hopsital death from primary VF
b) hospital death from heart failure
c) late deaths from:
i) recurrant ischaemic events
ii) lethal arrhythias
1) get pt to defibillator ASAP
2) reperfusion therapy ASAP
3i) secondary prevention therapy
ii) implantable defibrillator
