Myocardial infarction (A&E) Flashcards
(Relevant cards copied and pasted from ACS)
How can you differentiate between LBBB and RBBB on ECG?
- LBBB: WiLLiaM (W in V1, M in V5/V6)
- RBBB: MaRRoW (M in V1, W in V5/V6)
What type of MI is LBBB most likely to be?
Anterior-anteroseptal MI
What are some causes of LBBB? (1 + 5)
Always pathological:
- MI
- hypertension
- aortic stenosis
- cardiomyopathy
- hyperkalaemia
What are some causes of RBBB? (3)
- can be normal - more common with increasing age (vs LBBB - always pathological)
- RVH
- chronically increased RV pressure (cor pulmonale)
What are some clinical features of ACS/MI? (10)
- acute central chest pain
- dull, squeezing tightness
- radiates to left chest, arm, shoulder, neck, jaw
- crushing
- dyspnoea (SOB)
- sweating
- pallor
- nausea and vomiting
- palpitations
- syncope and dizziness
What is an atypical presentation of ACS/MI?
Painless in elderly and diabetics - presentation includes syncope, pulmonary oedema, epigastric pain and vomiting
How can an MI cause mitral regurgitation and what would you see on examination?
- due to rupture of the tendinous cords that usually hold the valve in place
- flash pulmonary oedema seen in patient
What is a complication of MI that causes S3 + S4 heart sounds?
- left ventricular aneurysm - due to significant damage to part of the ventricular muscle –> weakening
- patients present with tiredness and breathless
- persistent ST elevation on ECG (still there from previous MI)
- can lead to left ventricular thromboembolism –> embolic stroke or other systemic embolisms
What do S3 and S4 heart sounds suggest?
- S3 - LV is larger than normal (as S3 represents sloshing of blood into large ventricle during diastole)
- S4 - LV is stiffer than normal (as S4 represents the forceful atrial push of blood against a hard ventricular wall)
- therefore S3+S4 = LV is larger than usual, with stiff walls and causing pulmonary congestion
What do you see on ECG of left ventricular aneurysm (complication of MI)?
- persistent ST elevation in V1-6 on ECG
- as fibrosis and dead tissue is not able to properly move as expected
What are the symptoms of left ventricular free wall rupture post-MI? (3)
- raised JVP
- pulsus paradoxus
- diminished heart sounds
How do we treat left ventricular free wall rupture post-MI?
Urgent pericardiocentesis and thoracotomy
Compare NSTEMI vs STEMI.
- NSTEMI - ischaemic ECG changes, elevation of troponin/CK
- STEMI - ST elevation on initial ECG, elevation of troponin/CK, complete occlusion, transmural infarction
What are the risk factors for ACS/MI? (10)
- male
- diabetes mellitus
- Fx
- hypertension
- hyperlipidaemia
- smoking
- age
- obesity
- sedentary lifestyle
- cocaine use
What are the 1st-line investigations for ACS? (4)
- 12-lead ECG - best initial test to differentiate STEMI & NSTEMI
- cardiac biomarkers - troponin & CK-MB
- bloods
- CXR
What is seen on an ECG in NSTEMI? (2)
- ST depression
- T wave inversion
- (transient ST elevation)
What is seen on an ECG in STEMI? (5)
- persistent (>20min) ST elevation in 2+ contiguous leads:
- leads V2-3: men<40=2.5mm, men>40=2mm, women=1.5mm
- 1mm in other leads (II, III, avF, aVL)
- new LBBB (WiLLiaM)
- hyperacute T-waves
- T-wave inversion
- pathological Q-waves
What is PAIL (MI ECG)?
- Posterior-Anterior-Inferior-Lateral
- ST elevations in these leads most commonly create reciprocal ST depressions in the corresponding leads of the next letter of the mnemonic
In which types of ACS are cardiac troponin levels raised?
- NSTEMI
- STEMI
- (not unstable angina)
How often do you repeat cardiac troponin levels after MI?
After 1-6 hours