1. Bronze Level Electrocardiography

2. Aims Brief summary of relevant clinical electrophysiology
Indications for taking an electrocardiogram (ECG)
How to obtain a diagnostic ECG
Basic ECG interpretation

3. Section 1 – electrophysiology for clinicians

4. Unique properties of cardiomyocytes
Electrical syncytium
This means that the cells are coupled together in a way that permits rapid conduction of electrical impulses
Automaticity
This describes the ability of cardiomyocytes to spontaneously depolarise. Under normal conditions the cells of the sinoatrial node have the fastest rate of spontaneous depolarisation and therefore are the dominant pacemaker cells.

5. What is the ECG measuring?
Electrical activity detected at the body surface
Cardiac tissue
Neuromuscular tissue (= movement)
Movement artefact such as trembling results in irregular baseline movement as shown below:

6. Einthoven’s triangle
Dr Einthoven invented the first practical ECG in 1903
Einthoven’s triangle refers to the imaginary equilateral triangle formed by the 3 standard limb leads
Left forelimb Left hindlimb
- Lead III +
- Lead II
Lead I
The dots demonstrate the standard electrode positions

7. Anatomy of the intracardiac conduction system
Sinoatrial node (SAN)
Bundle of His
Atrioventricular node (AVN)
Left bundle branch
Right bundle branch
Right Left

8. Origin of -QRS-T P ECG: -VE (Right forelimb in lead II) P
Wave of depolarisation moves from sinoatrial node across atria from right to left thereby creating a flow in current towards the positive electrode
+VE
(Left hindlimb in lead II)
Right Left

9. Origin of P- RS-T Q ECG: -VE (Right forelimb in lead II) P Q
Small delay as impulse traverses AVN hence trace returns to baseline.
Depolarisation of the proximal interventricular septum then creates a small negative deflection – the Q wave.
+VE
(Left hindlimb in lead II)
Right Left

10. Origin of P- Q S-T R ECG: -VE (Right forelimb in lead II) P QR
Wave of depolarisation moves rapidly through the conduction system to the heart apex thereby creating a flow in current towards the positive electrode – the R wave
+VE
(Left hindlimb in lead II)
Right Left

11. Origin of P- QR -T S ECG: -VE (Right forelimb in lead II) P Q R S
Wave of depolarisation moves from the cardiac apex towards the heart base
+VE
(Left hindlimb in lead II)
Right Left

12. Origin of P- QRS- T ECG: -VE (Right forelimb in lead II) P QRS T
Wave of depolarisation moves from sinoatrial node across atria from right to left thereby creating a flow in current towards the positive electrode
+VE
(Left hindlimb in lead II)
Right Left

13. Section 2 - Indications for obtaining an ECG
Common indications:
Document heart rate and rhythm
Dysrhythmia on auscultation
Less common indications:
Electrolyte abnormalities
Suspected drug toxicity
Suspected cardiac chamber enlargement

14. Section 3 - Obtaining a diagnostic ECG

15. Patient set up for conscious ECG
Patient calm and still
Good electrical contact
Clips over bony areas to reduce muscle artefact
50mm/s in leads I, II, III, aVL, aVR and aVF
25mm/s rhythm strip for 1-5 minutes

16. Machine set up for conscious ECG
Is this the machine that is commonly used in the clinics?
If so then I can expand on order of button pressing.
If not then prob more helpful if we use the machine that is in the clinics for the images / movie of actually taking the ECG.

17. Set up for monitoring ECG
Multi-parameter monitors
Tape ensures good contact between electrode and pad

18. Muscle movement artefact
A common artefact seen on ECG is movement artefact caused by electrical activity present in moving muscles being detected by the ECG
This results in rapidly undulating baseline movement which does not disrupt the superimposed heart rhythm.

19. Now move onto the second slide show