Electrocardiography

An Electrocardiogram Records the electrical impulses associated with cardiac contraction and relaxation.

ECG Uses: Identifies rhythm disturbances, conduction abnormalities and electrolyte imbalances. Contributes information about the size of the heart chambers and the relative position of the heart in the chest. Documents the diagnosis and progression of myocardial infarction (MI). Monitors recovery from MI. Monitors drug effects. Evaluates the function of artificial pacemakers.

Electrocardiography (ECG) Technician Performs the EKG (ECG) May work in hospitals, medical offices, cardiac rehab centers or other health care facilities.

Educational Requirements: On the job training from 8 to 16 weeks One-year certification programs available

Responsibilities: Provide client instructions. Perform a safe and accurate tracing of the EKG. Ensure that the results are placed in the client’s chart. Maintain the EKG equipment.

Patient Preparation: The most important factor is to make sure the patient is relaxed. (informed and comfortable) The patient should be lying comfortably on a bed, stretcher or table wide enough to support his arms and legs. Remove shoes, loosen clothing and keep the patient warm.

Recording position: Most comfortable to work from the left side of the patient, where you are closest to the patient’s heart. To prevent artifacts, always keep the power cord pointing away from the patient and never run the cord under the bed.

Prepping the Patient: Since skin is a poor conductor of electricity, it may be necessary to prep the skin. If the patient is extremely hairy, you may need to shave small areas to ensure good adhesion. If the skin is oily, use and alcohol prep and let dry. Always apply electrodes before entering patient info into the machine to allow electrolyte material to interact with the skin.

Electrodes:

Attaching the Leads to the Electrodes Most lead wires are color coded to ensure the proper lead wire is connected to the proper electrode. Make sure the lead cables follow the patient contour and lay flat against the patient’s body. Avoid large loops.

Limb Lead Placement:

Electrodes:

ECG Paper

Cleaning and storing the ECG Clean the lead wires and machine. (Usually wiped down with a cloth moistened with disinfectant.) Throw away disposable electrodes in proper containers. Drape the lead wires of the machine in an orderly fashion. Return the machine to the designated storage location.

The ECG Complex Three words describe the activity of the heart: Polarized Depolarization Repolarization

Polarized-the heart at rest Polarized-the heart at rest. No impulse, no stimulation, no contraction and no measurable activity. Depolarization-activity of the heart during the impulse that causes contraction, but not the contraction itself. (can be measured by the ECG) Repolarization-the electrical recovery of the heart as the cells recharge themselves. (can be measured by the ECG)

P Wave The first wave to appear on the ECG. The impulse that causes the atria to contract. (Depolarization)

PR Interval The lapse of time between the beginning of atrial contraction and the beginning of ventricular contraction. (The beginning of the P wave to the onset of the QRS complex.)

QRS Complex Ventricular depolarization, or the journey of the electrical impulse from the AV node through the Purkinje network.

QRS Interval The period of ventricular depolarization

ST Segment The transition period between the conclusion of ventricular contraction and the beginning of electrical recovery (repolarization).

T Wave Represents repolarization of the ventricle, as the cells recharge themselves in preparation of another impulse.

Normal Sinus Rhythm Rhythm: Regular Heart Rate: 60-100 beats per minute

Sinus Tachycardia The heart beats faster than normal. Rhythm: Regular Rate: 100-150 beats per minute Cause: Excitement, exercise, pain, fever, hypotension and other causes. Treatment: treat the underlying cause.

Sinus Bradycardia The heart rate is slower than normal. Rhythm: Regular Rate: 40-59 beats per minute Cause: medications, hypothermia, increased intracranial pressure, inferior MI, and other causes. Treatment: give Atropine IV.

Sinus Arrhythmia Normal rhythm of the heart is absent. Rhythm: Irregular Rate: 60-100 Cause: Normal phenomenon commonly associated with the phases of respiration. Treatment: None