ECGs - everything else Flashcards
Draw the axis with deviation labelled
What can RAD mean?
- RV strain/RV hypertrophy
OR - Left posterior fascicular block (left posterior branch of purkinje fibres)
What does LAD mean?
- LV strain/LV hypertrophy
OR - Left anterior fasicular block
What can cause RAD from RV strain?
Massive PE
What can cause LAD from LV strain/hypertrophy?
- Early hypertension
- Severe aortic stenosis
How many wires make up purkinje fibres?
3 - 1 right, 2 left (posterior and anterior)
What is bifasicular block?
- LBBB
OR - RBBB + left posterior OR anterior fasciular block
What is complete heart block?
All blocked - LBBB (2) + RBBB (1)
What is trifasicular block?
- 2 and a bit wires blocked
- RBBB + LPFB/LAFB
- PR prolongation
What happens if trifascicular block and experiencing loss of conc?
Pacemaker needed - episodes of heart stopping
If this is NOT happening - we do NOTHING for trifasciular block
3 types of P waves
- Mitrale - M shaped
- Normal
- Pulmonale - tented up
Cause of p wave mitrale
- Was rheumatic fever
- Now often suggests large left atria
Cause of p wave pulmonale
- Cor pulmonale
- RA increased size
3 types of PR interval
Long
normal
Short
PR interval is measured from…
P wave to QRS complex start
Normal PR interval
120 - 200ms
3-5 small squares
When to be concerned aboit a PR interval (3)
- Very long - more than 280ms
- Other conductive tissue disease eg axis deviation?
- Infective endocarditis of aortic valve - sign of aortic root abscess
When is PR interval short?
When depolarisation is via an accessory pathway - AV node cannot conduct quicker than 0.12 ms
When is WFW present?
Often when someone is relaxed
Stress free
Caffeine can mask symptoms
What is Q wave a sign of?
Full thickness myocardial infarction
Criteria for Q wave to be a Q wave
- very 1st deflection after P wave
- 1/4 of R wave
- In lead III there is no Q wave unless in lead II and avF or V1 and V2 etc
When to comment on Q waves?
Not really ever unless they are pathological ones
Questions to ask about QRS complex?
- Is there BBB?
- Is there LVH?
Normal QRS width
Ideally within 1 small square
Needs to be more than 120ms to be BBB (3 small squares)
Where to look for 1st for BBB?
Chest leads - if they are not broad there is incomplete BBB
How to tell if L or R BBB?
Look at V2
Is it under isoelectric line - Left
Is it above in M shape - R
How to tell if there is LVH?
- If S wave in V1 or V2 plus (add) R wave in V5 or V6 is more than 35mm
- If any S or R wave in chest lead is more than 30mm
- R wave in lead I plus (add) avL is more than 14mm
each small square is 1mm
two types of ST elevation
- MI shaped - regional to leads
- Pericarditis - saddle shaped, widespread
What ECG change do you get other than ST elevation in pericarditis?
PR depression - 1mm
Different types of ST depression
- Upsloping - nothing
- Horizontal - less reliable
- Downsloping - worst
6 types of T waves
- Normal
- Peaked
- Biphasic
- Flattened
- Inverted
- Markedly inverted
- Assymetrically inverted - strain on heart
All others apart from normal and assym suggest ACS
