1. The basic’s of a 12 lead ECG

2. What is an ECG?
A recording which measures the electrical activity and the rhythm of your heart
Extremely common test used across the hospital for a range of medical conditions.
Indications include:
- chest pain Pre-op Lung problems
Syncope Drug therapies
Palpitations Dialysis
Dizziness
SOB

3. QUICK REVIEW OF HEART Purpose Pumps blood to the body Basic Anatomy
4 chambers
2 sides
4 valves

4. The sinoatrial node (SA node) is the pacemaker where the electrical impulse is generated. This node is located along the posterior wall of the right atrium right beneath the opening of the superior vena cava. It is crescent shaped and about 3 mm wide and 1 cm long.
The impulse travels from the SA node through the internodal pathways to the atrioventricular node (AV node).
The AV node is responsible for conduction of the impulse from the atria to the ventricles. The impulse is delayed slightly at this point to allow complete emptying of the atria before the ventricles contract. The impulse continues through the AV bundle and down the left and right bundle branches of the Purkinje fibers.
The Purkinje fibers conduct the impulse to all parts of the ventricles, causing contraction (Guyton, 1982).

5. The ECG: PQRST

6. P wave: The atria contracting QRS: The ventricles contracting T wave: Recovery of the heart ‘refractory period’

7. Performing an ECG Simple yet ‘personal’ test Proper skin prep
Placement of the limb electrodes
Placement of the chest electrodes
12 leads/electrodes but 10 ‘wires’
Each lead provides a tracing, which is characteristic of a different view of the same electrical activity. 12 different angles of the same thing
- E.g: In a heart attack, you can use the leads and what changes are in each to determine which artery is occluded and causing the MI

8. Why skin prep?
Ensures good electrode-skin contact which creates a good tracing
Signals are not well picked up just off the top, dead surface of the skin, so need to get to the underneath layer so the electrolyte can reach the signals beneath.
Achieved by:
- Abrasion pads
- Alcohol wipes
- Soap and water
- Razors

9. Artefact
Baseline wander