Cardiology Flashcards
Signs of ischaemia on an ECG
1) Hyperacute tall T waves
2) ST changes
> 1mm in contiguous limb leads
> 2 mm in contiguous chest leads
New LBBB
3) Q waves (not in all)
4) T wave inversion
Posterior ECG - when to suspect
ST depression (ST elevation), tall T waves (inverted T waves), tall R waves (Q waves) in the anterior leads (V1-V4) - recipricol changes
flip ecg paper upside down - will look like a STEMI!
Want a posterior ECG - V7,8,9 on back in line with others,
Need ST changes > 0.5mm for a +ve STEMI diagnosis
Right ventricular infarct - when to suspect
Suspect in inferior MI
V1 > V2
ST elevation in V1
III > II in terms of elevation
V1 and III are on the right, so would have a bigger voltage than V2 and II, respectively
More prone to hypotension - less blood
go to lungs, less back to left side to pump out to the body = reduce CO -> more prone to hypotension with GTN
can do right sided ECG!
Wellens syndrome
Deeply inverted T waves or biphasic T waves in V2-V3
May have no chest pain, normal trop, otherwise normal ECG
Highly specific for stenosis of the proximal LAD - want cardiology input
How to interpret ECG in LBBB or a paced rhythm?
Sgarbosa criteria - remember that any QRS changes will result in ST and T wave changes. Want to know whether these are secondary to QRS changes or primary in nature.
Sgarbosa criteria
Dance with discordance, cry with concordance
Discordant = normal :D
ST elevation > 5mm
Concordant ST depression > 1mm
Concordant ST elevation > 1mm
These are very specific for ischaemia. If have then highly like have ischaemic. Not sensitive, so if these are absent, then does not rule out an ischaemic event.
Widespread ST depression on an ECG - what does this indicate?
left main coronary artery occlusion
Signs of left main coronary artery occlusion on ECG
1) Widespread ST depression
2) ST elevation > 1 mm in aVR
3) AT elevation in aVR > V1
If unsure on an ECG - what to do??
1) Repeat it, would expect the changes to be the same or worsen
2) If unsure with worsened ECG, escalate up to a senior and see what their opinion is!
Where are Q waves normal?
Lateral leads - I, aVL, V5, V6
What will QRS changes cause?
Changes to ST segment and T waves!
