Electrocardiography (ECG or EKG from the German Electrocardiogram) is a transthoracic (across the thorax or chest) interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body. The recording produced by this noninvasive procedure is termed an electrocardiogram (also ECG or EKG).

Electrocardiography (EKG)
Category: Cardiovascular system.
Subcategory: Graphic recording.
Material studied: Tracings made on special paper.
Estimated cost of test: $100.00.
Patient time for test: 15-20 minutes.
Reliability of test results: Good. Other tests, studies and clinical observations are necessary to establish a precise diagnosis.
Available as home self-test? No.

BEFORE THE TEST

Purpose of test:

• Helps identify inflammation or damage to the heart muscle.
• Helps identify abnormalities in the minerals that control the electrical activity of the heart.
• Helps identify various irregular rhythms (arrhythmias).
• Identifies enlargement of the various chambers of the heart.
• Identifies the site and extent of damage to the heart muscle from myocardial infarction*.
• Monitors recovery from myocardial infarction*.
• Monitors effectiveness of certain drugs that may affect the heart.
• Determines how well a pacemaker is functioning.Where is test performed?
• Commercial laboratory, hospital, doctor’s office.Who performs test?
• Lab technician, nurse, doctor.Risks and precautions:
• Tell your doctor if you are taking any heart medications because certain medications can affect the interpretation of the EKG.Patient preparation:
• Activity–No changes necessary.
• Diet–Do not eat any foods or drink any beverages containing caffeine for 24 hours before the test.
• Medicines–Inform the person performing the test i24f you have recently taken any medications listed under Taking these drugs may affect test results. You may be asked not to take this medication before the test.
• Disrobing–Remove all clothing. Put on surgical gown.
  

  THE TEST

  Sensory factors:

• Touching–Slight abrasion to the skin during preparation to attach electrodes causes mild discomfort.
• Seeing–You will see the technician, nurse or doctor, the basket or tray to hold the equipment, the needles, syringes, collecting tubes and bandages.
• Feeling–Some degree of apprehension or fear is normal and should be expected. Discomfort disappears when the test is finished.
• Other senses (taste, smell, hearing)–Not affected.Equipment used:
• EKG machine, with amplifier.
• Strip-chart recorder.
• 5 lead wires.
• 4 electrodes with rubber straps.
• Suction cup chest electrodes.
• Special EKG paste or small pads soaked in alcohol or saline solution.
• 4×4 gauze pads.46
• Towel.Description of test:
• Electrodes are attached to arms, legs and chest.
• You may feel some mild discomfort during the preparation of these areas when skin is abraded.
• You must lie still and relax.
• Breathe normally during the procedure.
• Do not talk during the test because your voice may distort the EKG tracing.
  

  AFTER THE TEST

  Immediate post-test care:

• None.Activity after test:
• Electrode paste is wiped off with a damp cloth.Time before test results available:
• Time before results are reported to the doctor or patient varies from a few minutes to a few days.
  

  TEST RESULTS

  Test values:

• Test results are determined by the electrical current generated by the heart. Current radiates from the heart in all directions. Upon reaching the skin, it is measured by electrodes connected to an amplifier and strip-chart recorder.Normal values:
• No abnormalities.What ABNORMAL may indicate:
• Arrhythmias*.
• Conduction defects.
• Effects of cardioactive drugs.
• Electrolyte abnormalities, such as hypokalemia*.
• Ischemia*.
• Myocardial infarction*.
• Pericarditis*.
• Right- or left-bundle-branch block.
• Right or left ventricular hypertrophy*.
• Sometimes an EKG only reveals abnormal wave forms during episodes of symptoms, such as angina*, or during exercise.Taking these drugs may affect test results:
• Diet pills.
• Digitalis preparations.
• Digoxin.
• Digitoxin.
• Potassium.
• Sedatives.Other factors that may affect test results:
• Caffeine.
• EKG-machine malfunction.
• Improper placement of electrodes.
• Electromagnetic interference.
• Inadequate or ineffective electrode paste.
• Movement on your part.
• Muscle tremor.
• Strenuous exercise before the8: test. *See Glossary.