1. Recording ECG’s

2. Objectives Describe the heart’s conduction system.
State the purpose of electrocardiography.
Describe the responsibilities of the MAA when running an ECG
List the patient instructions (upon booking the appointment).
Identify all 12-leads and
Demonstrate the lead placement
List all artifacts
Run a 12-lead ECG

3. Structure of the Heart

4. Electrical System of the Heart
Path of impulse
1. SA node Electrical impulse discharged by SA node Impulse distributed to right and left atria: causes atria to contract
2. Impulse picked up by atrioventricular (AV) node AV node delays impulse momentarily Impulse transmitted to bundle of His
3. Bundle branches: relays impulse to the Purkinje fibers
4. Distribute impulse evenly to right and left ventricles

5. Purpose of an ECG Purpose of electrocardiography:
Evaluate the following symptoms:
Chest pain
Shortness of breath
Dizziness
Heart palpitations
Detect abnormality in heart rate or rhythm (dysrhythmia)
Detect presence of impaired blood flow to heart muscle (cardiac ischemia)
Help diagnose damage to heart caused by myocardial infarction
Determine the presence of hypertrophy of the heart

6. Purpose Con’t Detect myocarditis or pericarditis
Assess the effect on the heart of digitalis or other cardiac drugs
Determine the presence of electrolyte disturbances
Assess the progress of rheumatic fever
Detect congenital heart defects
Performed before surgery to assess cardiac risk during surgery
As part of a complete physical examination

7. MAA Responsibilities MA responsible for running ECG, which includes
Preparation of the patient
Operation of electrocardiograph
Identification and elimination of artifacts
Care and maintenance of the electrocardiograph

8. Cardioperfect Video

9. Patient Preparation
Do not apply body lotion, oil, or powder on the day of the test.
2. Wear comfortable clothing and a shirt or blouse that can be removed easily
3. Do not wear panty hose or tights.

10. 12-Lead ECG (The ABC’s of ECG/s
LEADS are strategically placed on the body to pick up the impulses throughout the body. This tells us if the electrical current is travelling throughout the body.
Augmented Leads
aVR aVL aVF
Bipolar Leads I
II (also shows rhythm) III
Chest Leads
V1, V2, V3, V4, V5, V6
ELECTRODES
Transmit electrical impulses given off by the heart to the machine through LEAD WIRES
The back of the electrodes contain an electrolyte gel which helps with conduction.

11. Lead Placement

12. Lead Application Video

13. Interpretation

14. Artifacts
Artifact: additional electrical activity picked up by electrocardiograph and Interferes with normal appearance of ECG cycles
Types
Muscle
Wandering baseline
60-cycle interference (AC artifact)

15. Muscle Artifact Characterized by Fuzzy, irregular baseline
The MA should always look at the printout to determine if an artifact is present.
Ask students to suggest ideas for remembering the appearance of a muscle artifact.

16. Muscle Artifact (Cont.)
Due to
Involuntary muscle movement (somatic tremor)
Voluntary muscle movement
Caused by
Apprehensive patient – to correct:
Reduce apprehension: relaxes muscles – explain the procedure; reassure patient that ECG is painless
Patient discomfort – to correct:
Make patient more comfortable: ensure table is wide enough to support patient’s arms and legs; place pillow under patient’s head; ensure room temperature is comfortable to patient (patient has removed clothing and may be cold; can cause shivering)
What is an example of involuntary muscle movement?
What is an example of voluntary muscle movement?

17. Muscle Artifact (Cont.)
Caused by
Patient movement – to correct:
Instruct patient to lie still and not to talk
Physical condition (e.g., Parkinson's disease)
Nervous system disorder that may prevent relaxation (e.g., Parkinson’s disease) – patient trembles continuously
Difficult to obtain an ECG free of artifacts
What would you do if the patient had a coughing spell while you were recording the ECG?
What other physical conditions are accompanied by shaking?

18. Wandering Baseline Artifact
Ask students to suggest ideas for remembering the appearance of a wandering baseline artifact.

19. Wandering Baseline Artifact (Cont.)
Caused by
Loose electrodes
Results in poor transmission of electrical impulse
To correct: ensure electrodes are attached firmly to patient's skin
If electrode pulls loose: reattach with tape; replace with a new electrode
Ensure clips are firmly attached to electrodes
Ensure patient cable is well supported on patient's abdomen or table to prevent pulling of lead wires on electrodes – can cause electrodes to pull away from skin
Do not allow cable to dangle
When should a new disposable electrode be applied if an electrode comes loose? (If the electrolyte has dried out.)

20. Wandering Baseline Artifact (Cont.)
Caused by
Dried-out electrolyte on electrode
Prevents good adhesion of electrodes to skin – to correct:
Replace it with a new electrode
Check expiration date stamped on electrode pouch (or box) to make sure within the expiration date
Body creams, oils, or lotions on skin at electrode application site – to correct:
Remove by rubbing with alcohol using friction
Excessive movement of the chest wall during respiration
REMEMBER: When should a new disposable electrode be applied if an electrode comes loose? (If the electrolyte has dried out.)

21. 60-Cycle Interference Artifact
Also known as AC artifact
Due to electrical interference
Electric current can leak out
From power used by electrical appliances in room
May be picked up by patient and carried into machine – results in a 60-cycle interference artifact
The ECG should be plugged into an outlet by itself.
What are some examples of electrical appliances that might be present in an examining room?
Does the patient need to remove jewelry for the ECG procedure?

22. 60-Cycle Interference Artifact (Cont.)
Appearance of 60-cycle interference artifact
Small straight spiked lines that are consistent
Causes baseline to be thick and unreadable
What is the difference in appearance between an AC artifact and a muscle artifact?
Ask students to suggest ideas for remembering the appearance of a wandering baseline artifact.

23. 60-Cycle Interference Artifact (Cont.)
Caused by
Lead wires not following body contour
Dangling lead wires pick up electric current – to correct:
Arrange lead wires to follow body contour and to lie flat
Other electrical equipment in room: may leak electric current – to correct:
Unplug nearby electrical equipment (lamps, autoclave, electrically powered examining table)
Let the patient know you are adjusting the wires. Why is this important?

24. 60-Cycle Interference Artifact (Cont.)
Caused by
Other electrical equipment in room: may leak electric current
Wiring in walls, ceiling, floors – to correct:
Move patient table away from walls
Improper grounding of the electrocardiograph
Machine is automatically grounded when plugged in (by three-prong plug)
Check plug: to make sure prongs are not loose or damaged
Ensure plug is securely in wall outlet
RL electrode picks up electric current from patient and carries it into machine – electric current is then carried away by grounding system of machine
Jewelry and watches do not interfere with recording. It is not necessary to remove them unless they interfere with placement of electrodes.

25. Interrupted Baseline Artifact
Check all equipment before use.
How would you store the wires when finished with a patient?

26. Interrupted Baseline Artifact
Caused by
Metal tip of lead wire becoming detached from alligator clip – to correct:
Reattach lead to alligator clip
Frayed or broken patient cable – to correct:
Replace patient cable
Check all equipment before use.
How would you store the wires when finished with a patient?