Vectorcardiography (VCG)

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Category: Cardiovascular system.
Subcategory: Graphic recording.
Material studied: Graphic recordings of electrical potential generated by the heart.
Estimated cost of test: $50.00 to $200.00.
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.
Note: Test creates a 3-dimensional view of the electrical activity of the heart. To do this, vectorcardiography (VCG) simultaneously views the heart from two of three planes being monitored. By viewing these two planes simultaneously, the VCG machine displays vector loops of the heart's electrical activity on it oscilloscope screen.

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BEFORE THE TEST

Purpose of test:

• Detects ventricular enlargement, heart-chamber disturbances and myocardial infarction.
• Clarifies doubtful or abnormal electrocardiograms.

Where is test performed?

• Commercial laboratory, hospital, doctor's office, outpatient or freestanding surgical facility.

Who performs test?

• Lab technician, nurse, doctor.

Risks and precautions:

• Tell your doctor if you take any cardioactive drugs, such as anti-arrhythmics.

Patient preparation:

• Activity - No changes necessary.
• Diet - No changes necessary.
• Medicines - Inform the person performing the test if 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 - Microphones on chest may feel cool at first.
• Seeing - You will see the technician, nurse or doctor, the basket or tray to hold the equipment, the oscilloscope screen and sensitive electronic recording instruments.
• Feeling - Some degree of apprehension or fear is normal and should be expected. Discomfort disappears when the test is finished.
• Other senses (smell, hearing, taste) - Not affected.

Equipment used:

• Electrodes.
• Vectorgraph recorder.
• Oscilloscope screen.

Description of test:

• This test is similar to electrocardiography (EKG); it is safe and painless.
• Electrodes to which conductive jelly has been applied are secured to your chest, left leg, back and nape of the neck or forehead. The number and placement of electrodes varies, depending on the system the doctor elects to use.
• You are instructed to breathe quietly.
• Avoid talking and remain still during the test.
• Recordings of electrical impulses of the heart are made.

AFTER THE TEST

Immediate post-test care:

• None.

Activity after test:

• Conductive jelly is removed from your skin.
• Return to pretest activities right away.

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 studying graphic recordings of variations in electrical potential during heart cycle.

Normal values:

• No abnormalities.

What ABNORMAL may indicate:

• Bundle-branch blocks.
• Myocardial infarction.
• Ventricular enlargement.

Taking these drugs may affect test results:

• Anti-arrhythmics.
• Digitalis.

Other factors that may affect test results:

• Incorrect placement of electrodes.
• Excessive movement on your part.

From the Complete Guide to Medical Tests by H. Winter Griffith, M.D. © 1988 by Fisher Books; electronic rights by Medical Data Exchange.