Electrocardiography Unit Health Article

KEY TERMS

Bipolar—A type of lead having one positive and one negative electrode

Bradycardia—An abnormally slow heartbeat.

Bundle of His—A group of special heart muscle fibers that transmit electrical impluses to the ventricles, beginning the contractions that pump blood into the aorta and pulmonary artery.

Depolarization—The movement of an electrical charge through nerve or muscle tissue, changing its voltage.

Einthoven's triangle—The triangular arrangement of EKG electrodes on a patient, generally including the right arm, the left arm, and the left leg.

Electrode—The point of connection between the EKG unit and the patient.

Isoelectric—The baseline electrical level of the body.

Lead—A conductive connector between the electrode and the EKG unit or the signal derived from a group of electrodes.

Repolarization—The process in which a nerve or muscle cell returns to its normal electrical state after depolarization.

Tachycardia—An abnormally fast heartbeat.

Unipolar—A type of lead having one positive and multiple negative electrodes.

three of the layers of the heart have been affected by the attack, the Q wave will deflect more negatively. To be considered abnormal, the Q wave must be at least 0.04 seconds long (one small box) and be at least 25% of the height of the R wave. The Q wave will start large and shrink some over time, but will always be present after a so-called "Q-Wave" MI.

It is important to rule out artifacts as the cause of a patient's abnormal EKG. Common artifacts are patient movement, loose or defective electrodes, clammy skin, excessive chest hair, or improper grounding. The rule of thumb is to look to the patient and treat their distress, not what is showing on the monitor.

Maintenance

Electrocardiograph technicians are in charge of maintenance of EKG machines. Their tasks include changing graph paper and ink, maintaining the electrodes and leads, and monitoring the machine for malfunction.

Health care team roles

Specially trained assistants known as electrocardiograph technicians often operate and maintain EKG machines in larger hospital and cardiology group practice settings. In small settings, nurses and medical assistants perform the test. A doctor usually does the final interpretation of the tracing.

Training

Many persons learn how to use an EKG machine through on the job training. However, training programs are available through outsourcing companies or in vocational and community colleges. The usual length of these college-based programs is 465 hours (four months). Program content includes classroom instruction in anatomy and physiology with an emphasis on the cardiac and vascular system, medical terminology, cardiovascular medications, patient care techniques, interpretation of cardiac rhythm, medical ethics, and a clinical practicum.

BOOKS

Beasley, Brenda M. Understanding EKGs: A Practical Approach. Upper Saddle River, NJ: Prentice Hall, 1999.

Dubin, Dale. Rapid Interpretation of EKGs: An Interactive Course. Tampa, FL: Cover Publishing Company, 2000.

PERIODICALS

Miracle, Vickie A. "Making Sense of the 12 Lead ECG." Nursing 99 (July 1999): 34.

ORGANIZATIONS

Alliance for Cardiovascular Professionals. 910 Charles Street, Fredericksburg, Virginia 22401. 540-370-0102.

OTHER

Yanowitz, Frank G. "The Standard 12 Lead ECG." The Alan E. Lindsay ECG Learning Center in Cyberspace. <http://medstat.med.utah.edu/kw/ecg/ecg_outline/Lesson1/index.html> (April 5, 2001).

Michelle L. Johnson, M.S., J.D.