Recording ECG’s

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

Structure of the Heart

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

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

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

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

Cardioperfect Video

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.

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.

Lead Placement

Lead Application Video

Interpretation

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)

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.

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?

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?

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

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.)

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.)

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?

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.

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?

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.

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

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?