ECG Flashcards
What are the lateral leads?
I, AVL, V5 V6
What are the inferior leads?
II, III, AVF
What are the anterior leads?
V3, V4
What leads would you expect to have positive R waves?
Lead I, II, III, AVF, AVL
What is the only limb lead that will have a negative complex?
AVR
What happens to the presentation of an R wave as it moves throughout the leads?
It will progressively become positive and upright between V1 and V6
When the myocardium is damaged what functions are inhibited, and why?
Electrical conduction & muscle contraction are inhibited because the damaged area remains in a constant depolarised state.
How would the ST segment differ to normal in an infarct and in ischaemia?
Infarct = ST elevation
Ischaemia = ST Depression
What doe STEMI stand for?
ST Elevation Myocardial Infarct
Pt can be classified into 3 groups as a result of ST Segment and T wave changes. What are those 3 groups?
STEMI: ST elevation of >1mm (limb) and >2mm (chest) in two or more continuous leads.
High-Risk Unstable Angina: Ischemic ST depression >0.5mm or dynamic T wave inversion w/ pain.
Normal or non-diagnostic changes: Findings are inconclusive. >0.5mm ST deviation or >0.2 T wave inversion with no pain.
What is the 5 step analysis for infarct recognition?
STEP 1:
- Identify rate and rhythm
- Manage any life-threatening dysrhythmias (SVT, Symptomatic bradycardia, VT, VF)
STEP 2:
- Identify the area of infarct through 12 lead ECG.
- look for ST segment elevation
- If ST is present with chest pain, identify degree of elevation and visualise cardiac anatomy to predict which coronary artery is occluded.
- Look for opposite presentation in reciprocal leads.
- Extent of MI can be gauged by the number of leads showing ST elevation.
STEP 3:
- Consider other conditions that could be responsible for ST segment elevation e.g.
- Hypokalaemia has a peaked T wave which can sometimes pull the ST segment up with it.
- Global ST elevation = pericarditis
- Ventricular rhythms can show ST elevation however will not have reciprocal ST depression.
STEP 4:
- Assess the pt clinical presentation with A-E
- Maintain high degree of suspicion in absence of pain, especially in diabetics, elderly, postmenopausal women
STEP 5:
- Recognise infarction and initiate care.
What are the placements for chest leads?
V1: Fourth intercostal space to the right of the sternum
V2: Fourth intercostal space to the left of the sternum
V3: Directly between V2 and V4
V4: Fifth intercostal space at left midclavicular line
V5: level with V4 at left anterior axillary line
V6: level with V5 at left midaxillary line
If you see significant ST depression in anterior leads what might this indicate?
Posterior MI
The anterior leads may be showing reciprocal readings of the posterior.
What are the contiguous lead groupings?
Inferior wall - II, III, AVF
Lateral wall - I, AVL, V5, V6
Septum - V1 & V2
Anterior wall - V3 & V4
What would ST elevation in leads II, III and AVF indicate?
Inferior infarct
