Acute coronary Syndrome and Myocardial infarction Flashcards
What is the definition of an MI
Rise and/or fall of troponin with at least one value >99th percentile of the URL, plus at least one of the following:
- Cardiac chest pain
- ECG changes (new ST-T change or new LBBB)
What are the two types of AMI
- STEMI
- NSTEMI - unstable angina
Describe what happens in an NSTEMI
- ruptured coronary plaque with subocclusvie thrombus
- ECG non diagnostic
Describe what happens in a STEMI
- Ruptured coronary plaque with occlusive thrombus
- ECG diagnostic
What troponin is used in to see if you have an MI
Troponin I and T
- specific to the heart
What are the classifications of AMI
Type 1
- spontaneous AMI
- due to plaque rupture
Type 2
- ischaemic imbalance
- due to coronary spasm, embolism , dissection, hypotension
Type 3
- cardaic death
- due to presumed AMI
Type 4a
- related to PCR
- greater than 5 times URL for troponin
Type 4b
- caused by stent thrombosis
- confirmed at angiography or autopsy
Type 5
- related to CABG
- greater than 10 times URL for troponin
how many people die from AMI before they reach to hospital
33% of people who die from AMI do so before they reach hospital
who delays in calling for help with an AMI
- Older people
- Women
- Nocturnal or w/e pain
- No previous AMI
- People with diabetes
what are the determinants of infarct size
Anatomical
- distribution of occluded artery
- proximity of coronary occlusion
- collateralization of occluded artery
Physiological
- thrombotic response to plaque rupture
- effectiveness of endogenous thrombolysis
Therapeutic
- reperfusion therapy
- antiplatelet drugs
- drugs to protect against LV remodelling
Logistical
- time to call for help
- time to arrive at hospital
- time to delivery of reperfusion therapy
If the
- circumflex
- RCA
- LAD
is damaged where is the STEM on the ECG
- circumflex = lateral STEMI
- RCA = Inferior STEMI
- LAD - anterior STEMI
What is the pathway when a patient comes in complaining of chest pain
- Do an ECG = if it is diagnostic then Admit
- if ECG is non diagnostic then do a clinical assessment = if there is typical chest pain or heart failure or unstable rhythm then admit
- if there is atypical Chest Pain and rhythmically and haemodynamically stable then look at biomarkers
- if biomarkers are troponin positive then admit
- if biomarkers are troponin negative then the patient is a low risk patient
- send them home and consider a further out patient investigation
how is troponin used to rule out AMI in A and E
- Allows diagnostic thresholds to be set at very low levels
- Improves diagnostic sensitivty
- Endorsed by NICE for accelerating diagnostic pathways and reducing pressure on beds
How do you treat a STEMI
- Aspirin and ticagrelor (P2Y12 receptor antagonists)
- GpIIb/IIIa inhibitor
- unfractionated/LMWH
- PPCI
What type of drug is ticagrelor
P2Y12 receptor antagonists
What is the guidelines for treating a NSTEMI
Low risk - aspirin 300mg - fondaparinux - ticagrelor 300mg Then conservative management
Intermediate risk 3-6%
- aspirin 300mg
- fondaparinux
- ticagrelor 300mg
- consdier tirofiban/eptifibatide for intermiediate or high risk groups
- Coronary angiogram within 96 hours or earlier for unstable patients - PCI or CABG
High risk greater than 6%
- aspirin 300mg
- fondaparinux
- ticagrelor 300mg
- consdier tirofiban/eptifibatide for intermiediate or high risk groups
- Coronary angiogram within 96 hours or earlier for unstable patients - PCI or CABG
If you have a STEMI what do you get immediately
- Coronary angiography - then PCI or CABG
What are the two important complications in an MI (IMPORTANT - IN EXAM)
- Heart failure
- Arrhythmia
How do you treat heart failure
Diuretics
• IV frusemide
• Haemofiltration if
diuretic resistant
RAS Inhibition
• ACE-I or ARB
• Eplerenone
Inotropes
• Noradrenaline
• Dobutamine
LV support device
• Balloon pump?
• LVAD?
name the two types of Arrhythmia
Bradyarrhythmias
Tachyarrhythmias
Describe how an AV node block and complete AV node block
rate of depolarisation goes from fast, slower, much slower as you get down
- depending on where the conduction system is damaged it determines how serious it is
- if you have a block at the AV node that is not a DT - pacemaker in the bundle of his will take over - the patient will feel fine - usually gets better on its own
How do you treat intermittent AV node block and complete AV node block
- Atropine if rate slow
- pacing rarely needed
- sponteaneous recovery in less than 7 days
- prognosis is good
What happens if both bundle branches blocked
intermittent block of both bundle branches and complete block of both bundle branches
- large infarct
What causes blockage of the AV node
inferior MI
How do you treat intermittent block of both bundle branches and complete block of both bundle branches
- Pacing mandatory
- no spontaneous recovery
- prognosis poor
Name some types of tachyarrythmias
- atrial fibrillation
- VT, VF
How do you treat an atrial fibrillation
- Beta blocker
- DV cardioversion if haemodynamic compromise
- if arrhythmia persists needs anticoagulation with later consideration of rate vs rhythm control
What is the difference between early and late ventricular tachyarrhythmias
- ventricular tachyarrhythmias that complicate AMI usually occur in the first 12-24 hours when if corrected they have only minor prognostic impact
- but if late VT/VF after 24 hours presentation are a bad prognostic sign are predictive of sudden death in the first year
what treatment is for life expect
except P2Y12 receptor antagonist = ticagrelor
what is the prevention lifestyle
- smoking
- diet
- exercise
What are the prevention drugs
- aspirin 75mg and a second antiplatlet e.g. clopidogrel for at least 12 months to decrease stroke
- P2Y12 receptor antagonist
- statin
- beta-blocker - reduce myocardial oxygen demand
- ACE-I - in patients with LV dysfunction, hypertension or diabetes unless not tolerated
Name prevention devices
ICD
Name the life saving strategies in AMI
- Pre-hospital death from 1° VF–33% of all deaths
get the patient to a defibrillator ASAP - Hospital death from LVF–directly related to infarct size
initiate reperfusion therapy ASAP - Late deaths–variably related to infarct size a) Recurrent ischaemic events
2° prevention therapy
b) Lethal arrhythmias
implantable defibrillator in selected cases
What is the definition of acute coronary syndrome
The term ‘acute coronary syndromes’ (ACS) encompasses a range of conditions including unstable angina, non-ST-segment-elevation myocardial infarction (NSTEMI) and ST-segment-elevation myocardial infarction (STEMI) that are due to a sudden reduction of blood flow to the heart.
What conditions can acute coronary syndrome include
includes unstable angina and MIs, which share a common underlying pathology – plaque rupture, thrombosis and inflammation
What leads to a diagnosis of an Acute coronary syndrome
- increase in cardiac biomarkers (troponin)
Either
- symptoms of ischaemia
- ECG changes of new ischaemia
- development of pathological Q waves
- loss of myocardium
- regional wall motion abnormalities on imaging
What are the symptoms of acute coronary syndrome
- acute central chest pain lasting longer than 20 minutes
- nausea
- sweating
- dyspnoea
- palpitations
ACS without chest pain mostly seen in diabetic patients
- syncope
- pulmonary oedema
- epigastric pain
- vomiting
- post op hypotension or oliguria
- acute confusional state
- stroke
- diabetic hyperglycaemic states
What are the signs of acute coronary syndrome
- distress
- anxiety
- pallor
- sweatiness
- pulse raised or not
- BP either hypertensive or hypotensive
- 4th heart sound
May be signs of
- heart failure = Raised JVP, 3rd heart sound, basal crepitations
- pan systolic murmur
- low grade fever
What are differential diagnosis for retrosternal chest pain
- GORD
- Biliary colic
- pancreatitis
- MI
List the investigations that can be used to confirm the diagnosis of ACS
- ECG
- CXR
- Blood
- Cardiac enzymes
- Echo
What does an ECG look like in a STEMI
STEMI within hours - hyper acute tall T waves - ST elevation - new LBBB hours to days - pathological Q wave - T wave inversion
What does an ECG look like in an NSTEMI
- ST depression
- T wave inversion
- non specific changes or normal
Name 5 cardiac enzymes
- Creatine kinase
- CK cardiac isoenzyme
- Aspartate transaminase
- lactate dehydrogenase
- cardiac troponin
Name when the cardiac enzyme rises and for how long they remain high
Troponin
- goes to x50 of normal in first few hours
- remains high for 3 days and then starts to decrease until day 10 when it is normal
CK-MG
- goes high and peaks in 1 and a half days since MI
- falls to normal by half way through 2nd day
CK
- goes high and peaks around 2 days and then is normal by 3rd day
AST
- increases after 1 day and is normal by day 3
LDH
- increases from day 2 and slowly decreases till normal at day 10
IN terms of revascualrisation what is the difference between STEMI and NSTEMI
- STEMI - receive immediate angiography and PCI
- NSTEMI who are at high risk have angiography within 24 hours, immediate risk within 3 days and low risk may be considered for non invasive testing
What are the indications for CABG
Improve survival
- left main stem disease
- triple-vessel disease involving proximal part of the LAD
Relieve symptoms
- angina unresponsive to drugs
- unstable angina
- if angioplasty is unsuccessful
How does CABG work
- heart is stopped
- cardiac bypass
- patients own saphenous vein or internal mammary artery is used as the graft
What vessels are used as the graft in CABG
- saphenous vein
- internal mammary artery
How do you take a sublingual GTN
- used under the tongue
- either in tablet or spray form
Tablet
- 1 tablet under tongue as soon as possible, if still in pain 5 minutes later put another tablet and then if still in pain after 5 more minutes put another tablet
Spray
- 1 or 2 sprays under your tongue. If you’re still in pain after 5 minutes you can have a second dose of 1 or 2 sprays under your tongue. If you’re still in pain after 5 minutes you can have a third and final dose
What are the side effects of sublingual GTN
- headaches
- hypotension
What are the indications of coronary interventions in acute coronary syndrome
- high risk patients with ACS
- multi vessel lesion
What life style modification should you take if you are post ACS
- dietary recommendations including calorie control of obesity
- alcohol consumption maintained within safe limits
- patients should be physically active
- patients should stop smoking
- a healthy weight
- blood pressure should be reduced
- patients with diabetes need treatment
define a STEMI
ACS with ST elevation or new onset LBBB
Define a NSTEMI
- troponin-positive ACE without ST elevation, ECG may show ST depression, T wave inversion, non=specific changes or be norma
What is the management of acute STEMI
Dual oral antiplatelet therapy: Aspirin 300mg PO + Ticagrelor 180mg PO or Prasugrel 60mg PO if no Hx of stroke/TIA and <75yrs
- Previously: clopidogrel
Analgesia: Morphine 5-10mg IV + antiemetic (1st) Metoclopromide 10mg IV or (2nd) Cyclizine 50mg IV
Oxygen recommended if SaO2 <94%, breathless or acute LVF
Reperfusion therapy – must be early!
Anticoagulation – injectable anticoagulant must be used in primary PCI: Bivalirudin preferred, if not available use Enoxaparin ± GP IIb/IIIa blocker (eg Tirofiban)
Beta-blockers – eg Bisoprolol 2.5mg od; provide benefit if used early
CI: cardiogenic shock, HF, asthma/COPD or HB
What is the criteria for reperfusion therapy
- Typical clinical symptoms of MI
- ECG criteria - either of the following
- ST elevation>1mm in 2 or more adjacent limb leads or >2mm in 2 or more adjacent chest leads
- LBBB
- posterior changes: deep ST depression and tall R-waves in V1-V3
Name the types of reperfusion therapy
- 1st choice: Primary PCI
- 2nd choice: Thrombolysis
Describe when you should use primary PCI
- Should be offered to all patients presenting within 12h of symptom onset with a STEMI who either are at or can be transferred to a primary PCI centre within 120min of first medical contact
- If not possible thrombolyse & transfer patient after infusion for either rescue PCI (if residual ST elevation) or angiography (if successful)
- PCI use >12h from symptom onset requires specialist advice
When should you use thrombolysis
- benefit reduces steadily from onset of pain; target time is <30 minutes from admission
- thrombolysis use is >12 hours from symptom onset requires specialist advice
When do you not thrombolyse
- ST depression alone
- T wave inversion alone
- Normal ECG
Name the absolute contraindications to thrombolysis
- previous intracranial haemorrhage
- ischameic stroke < 6 months
- c cerebral malignancy or arteriovenous malformations
- recent major trauma/surgery/head injury less than 3 weeks ago
- GI bleeding less than 1 month ago
- known bleeding disorder
- aortic dissection
- non-compressible punctures < 24 hours e.g. liver biopsy, lumbar puncture
Name the relative contradinications to thrombolysis
- TIA less than 6 months ago
- anticoagulant therapy
- pregnancy or 1 week post party
- refractory hypertension
- advanced liver disease
- infective endocarditis
- active peptic ulcer
- prolonged/traumatic resuscitation
What is the long term symptom control of ACS
- manage chest pain with PRN GTN and opiates
- if insufficient consider GTN infusion
- if deteriorating seek senior help
What risk factors do you have to modify in long term management of ACS
- stop smoking
- identify and treat DM, HTN, hyperlipidaemia
- dietary advice: oily fish, fruit, vegetables fibre, decreased saturated fats
- encourage daily exercise; refer to cardiac rehab programme
- mental health: fall to GP if depression or anxiety present
What is the complication of ACS
- Cardiac Arrest
- Cardiogenic Shock
- LVF
