Lecture 18 Flashcards
What is acute coronary syndrome?
Signs and syndromes (unstable angina/STEMI/nonSTEMI) due to decreased blood flow in the coronary arteries, due toa ruptured atheromatus plaque and thrombus formation
What types of ECG can be viewed in acute coronary syndrome and what is the effect?
ST elevation: full occlusion
- mycardial damage= STEMI
- no damage= aborted STEMI
NO ST elevation: partial occlusion
(ST depression/T wave inversion)
-myocardial damage= NSTEMI
-no damage= unstable angina
What is the definition of an acute myocardial infarction?
Cardiomyocyte necrosis in a clinical setting consistent with acute myocardial ischaemia
What are some of the criteria for diagnosis of an acute MI?
- symptoms of ischaemia
- ST/T wave changes
- left bundle branch block
- pathological Q waves
- intracoronary thrombus detected on angiography/autopsy
- regional wall motion abnormality
How many types of MI are there, and define the first 2?
5 types
Type 1
-atherosclerotic plaque rupture/ulceration/fissure/erosion/dissection resulting in an intraluminal thrombus in a coronary artery leading to decreased myocardial blood flow and subsequent myocardial necrosis
Type 2
-condition other than a coronary plaque that contributes to an imbalance between myocardial oxygen supply and demand
Give some mechanisms resulting in type 2 MI:
- coronary artery spasm
- coronary endothelial dysfunction
- tachyarrhythmias, bradyarrhythmias
- anaemia
- respiratory failure
- hypotension
- severe hypertension
What do you need to ask about when taking the history?
- cardiac sounding
- where does the pain radiate to
- how long did the pain last
- is the pain getting worse
- is pain worse on inspiration (pleuritic)
- relieved with GTN? (glyceryl trinitrate- quick pain disappearing= cardiac problem)
What is the purpose of GTN?
Spray used to relieve angina by dilating blood vessels
What risk factorsdo you look for in a patient with suspected heart problems?
- smoker/vape
- family history
- high cholesterol
- hypertension
- thrombophilia
On examination of the patient what should you examine to do with haemodynamics?
- BP
- tachy/bradycardia
- JVP (jugular venous pressure)
- lungs (clear/wet- cracks= pulmonary oedema)
- heart sounds (mumur)
- cool peripheries
What BP is classed as cardiogenic shock?
<90 mmHg
High chance that patient will deteriorate and die
What are the ECG territories/location of infarct?
Lateral: V5, V6 Septal: V1, V2 Anterior: V1-V6 Anteroseptal: V1-V4 Anterolateral: V3-V6 Inferior: lead 2/lead 3, aVF High lateral: lead 1, aVL
What does ST elevation imply?
Sudden occlusion
What does ST depression/T wave inversion imply?
Under-supply of blood to myocardium but not sudden coronary occlusion
(ST depression can also be caused by sudden occlusion of vessel at back of heart: posterior STEMI)
What are the ECG signs evolving with ST elevation?
- hyperactue T waves (more prominent with wider base)
- ST segment elevation
- T wave inversion
- pathological Q waves
What is raised in coronary syndromes?
Troponin I/T
Raised within 3 hours of cardiac damage and stay elevated for 2+ weeks
What is an echocardiogram?
Ultrasound to image the heart (can be mobile)
- looks at it upside down
- coronal territory models
What can you view using an echocardiogram?
- LV function
- wall motion
- valvular disease
- complications from an MI
- ventricle septal defect
How do you manage a STEMI?
- aspirin 300mg
- second antiplatelet (ticagrelor: 180mg/prasugrel: 60mg)
- morphine 5-10mg with metaclopramide 10mg IV
- nitrate 2 puffs under tongue if BP >110 mmHg
- oxygen if <92%
- transfer for PCI
At what weight/age do you give a second antiplatlet?
> 60 kg
<75 yo
How do you manage an NSTEMI?
- antiplatelets/antithombotics (aspirin and clopidogrel/ticagrelor)
- anti-ischaemics (GTN infusion, bisopolol)
- secondary prevention
What are some methods of secondary prevention of a NSTEMI?
- statins (reduce cholesterol)
- ACE inhibitors
When would you do an urgent PCI?
NSTEMI
- patient has ongoing chest pain with dynamic ECG changes (changes from normal to abnormal suddenly)
- if patient develops arrythmias with compromise
What is a PCI?
Percutaneous coronary intervention
- local anesthetic
- 30 mins
- radial/femoral artery access
What is an invasive coronary angiogram?
X-Ray dye: contrast to opacitise coronary arteries to seeif there is an occlusion
If so:
-predilate the narrowed sections with balloons
-stent (metal scaffold) used to keep vessel patent
What is the management after a PCI?
- Lifestyle changes (low fat diet/regular exercise/low salt)
- Dual antiplatelets for a year and then aspirin for life
- statins to reduce cholesterol to <4mmol/L (LDL conc <2mmol/L)
- bisprolol to keep HR at 70bpm (beta blocker)
- ACE inhibitor to keep BP 140/80
- echo shows EF is <40% then give eplerenone
- echo at 3 months if ejection fraction is <35%= implantable cardiac defibrillator
What is the effect of beta blockers?
HR to fall with less contraction, therefore lowering BP
block effects of adrenaline
