Cardiac - Chest pain, arrhythmias, palpitations Flashcards
What makes up ‘Acute Coronary Syndrome’?
- STEMI = complete blockage of an artery
- NSTEMI = partial blockage of an artery
- Unstable angina = chest pain at rest due to narrowing of coronary artery
What is the common underlying pathology shared between the 3 ACS conditions?
Plaque rupture
Thrombosis
Inflammation
What do platelets release that cause vasoconstriction?
Thromboxane A2
Serotonin
What are the main risk factors for ACS?
Smoking Hypertension Hyperlipidaemia Diabetes mellitus Obesity Family history of IHD (MI in first degree relative <55 years) Cocaine use
How does ACS present?
Sudden onset of crushing central chest pain/tightness Pain radiates to back, jaw, left arm Acute dyspnoea Nausea and vomiting Sweating Palpitations
How can you distinguish between ACS and stable angina?
ACS is unresponsive to GTN spray
What would the ECG look like in a STEMI?
Tall tented T waves in hyper-acute
ST elevation OR new-onset LBBB (broad QRS complexes)
Inverted T waves if ECG done days later (shows ischaemia)
Q waves remain for months
How do you differentiate between an MI and unstable angina?
Troponin levels
What ECG changes can be seen in an NSTEMI?
ST depression
T wave inversion
(might be normal)
At what hours post-pain onset do troponin levels rise?
The levels increase 3-12 hours from pain onset
They peak at 24-48 hours
Return to baseline 5-14 days
What does ST elevation in leads II, III, aVF indicate?
Inferior MI in the right coronary artery
What does ST depression in leads V1-4 indicate?
Posterior MI in the posterior descending artery
V1-4 are anterior leads so think of it as an upside down ST elevation in the posterior side of the heart
What does ST elevation in leads V7 to V9 indicate?
Posterior MI in the posterior descending artery
What does a new LBBB indicate?
STEMI
What ECG changes would be seen in a blockage of the circumflex coronary artery?
Acute postero-lateral MI
Posterior infarct
- ST depression in V1-4
- Dominant R waves (= upside down Q waves)
Lateral infarct - ST elevation in V6
What does an anterior STEMI result from?
Occlusion of the LAD (left anterior descending artery)
What ECG changes are seen in an anterior STEMI?
ST segment elevation in the precordial leads (V1-6) ± the high lateral leads (I and aVL).
What is troponin?
Protein involved in cardiac and skeletal muscle contraction
When myocardial cells are damaged, troponins are released into the blood
Which troponins are most specific to the heart?
Troponins I and T
Aside from MIs what can cause a rise in troponin?
Other causes of myocardial damage:
- Myocarditis
- Pericarditis
- Ventricular strain
Non-cardiac aetiology:
- Masive PE causing right ventricular strain
- Subarachnoid haemorrhage
- Burns
- Sepsis
- Renal failure
What is the acute management of an MI?
MONAC
Morphine 5-10mg (given with metoclopramide)
Oxygen 15L/min
Nitrates - GTN spray
Aspirin/Clopidogrel 300mg loading dose
If STEMI, refer to cardiologist for PCI
Who should a primary PCI be offered to?
All patients presenting within 12 hours 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 PCI is unavailable or it has been >12 hours since symptom-onset, what should be done for patients with a STEMI?
Thrombolysis (-plase) Start fondaparinaux (factor 10a inhibitor) or LMWH
What advice should be given to patients post-MI?
Returning to work - 2-3 months
Driving - do not drive for 1 week if successful angioplasty, or 4 weeks if unsuccessful/no angioplasty, notify insurance
Sex - avoid for few weeks, return when able to walk without discomfort
What are the linings of the aorta?
Intima
Media
Adventitia
What happens in an aortic dissection?
Tear in the intima of the aortic lining, which allows blood to enter the aortic wall
A haematoma forms which separates the intima from the adventitia
A false lumen is created which extends in either direction
As the dissection extends it may damage the aortic valve or prevent circulation to the aortic branch vessels, leading to major ischaemic target organ complications