ELECTROCARDIAGRAM

An electrocardiogram (EKG, ECG) is a test that measures the electrical signals that control the rhythm of your heartbeat.  A natural electrical system causes the heart muscle to contract and pump blood through the heart to the lungs and the rest of the body.  The electrical activity of the heart can be detected through the skin by small metal discs called electrodes. During an electrocardiogram, the electrodes are attached to the skin on the chest, arms, and legs. The electrodes are also connected to a machine that translates the electrical activity into line tracings on paper. These tracings are often analyzed by the machine and then carefully reviewed by a doctor for abnormalities.

 An electrocardiogram may show:

• Evidence of heart enlargement.
• Signs of insufficient blood flow to the heart.
• Signs of a new or previous injury to the heart (heart attack).
• Heart rhythm problems (arrhythmias).
• Changes in the electrical activity of the heart caused by an electrolyte imbalance in the body.
• Signs of inflammation of the sac surrounding the heart (pericarditis).

Why It Is Done

An electrocardiogram (EKG, ECG) is done to:

• Evaluate unexplained chest pain, especially when a heart attack is a possibility. Other possible causes of chest pain or discomfort that can be identified by an EKG include irregular heartbeats (arrhythmias), a heart chamber with thickened walls (hypertrophy), inflammation of the sac surrounding the heart (pericarditis), and reduced blood flow to the heart muscle (ischemia).

• Monitor the heart's electrical activity.

• Determine whether thickening of the walls (hypertrophy) of a ventricle is present.

• Monitor the effectiveness and possible side effects of certain medications that may affect the heart.

• Check the function of mechanical devices (pacemakers or defibrillators) implanted in the heart to maintain a regular heart rhythm.

• An electrocardiogram may be used to evaluate symptoms of heart disease (such as unexplained chest pain, shortness of breath, dizziness, faintness, or palpitations) or when risk factors for heart disease (such as high blood pressure, high cholesterol, cigarette smoking, diabetes, or a family history of early heart disease) are present. 

How To Prepare

Tell your health professional if you are taking any medications. Certain medications can affect the results of your electrocardiogram.

 Talk to your health professional about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will indicate.

 How It Is Done

 An electrocardiogram (EKG, ECG) is usually done by a health professional, and the resulting EKG is interpreted by  one of the Heart Institute of the Caribbean’s electrophysiologist,  cardiologist, or surgeon.

 You should remove all jewelry from your neck, arms, and wrists. You will also need to remove your clothing above the waist and keep your forearms and lower legs exposed. If you are wearing stockings, you should take them off. You will be given a cloth or paper covering to use during the test.

 During an electrocardiogram, you will lie on a bed or table. Areas on your arms, legs, and chest where electrodes will be placed are cleaned and possibly shaved to provide a clean, smooth surface to attach the electrode discs. A special EKG paste or small pads soaked in alcohol may be placed between the electrodes and your skin to improve conduction of the electrical impulses, but in many cases disposable electrodes are used that do not requite paste or alcohol.

 Several metal electrodes or "leads" are attached to the skin on each arm and leg and on your chest. If an older machine is used, the electrodes may be repositioned at different times during the test to measure your heart's electrical activity from different locations on your chest. After the procedure, the electrode paste is wiped off.

 It is important not to move or talk during the recording because muscular activity can cause inaccurate results. For best results, lie very still and breathe normally. Sometimes you may be asked to hold your breath.

 An electrocardiogram usually takes 5 to 10 minutes to complete. Sometimes a longer period of recording (a "rhythm strip") is done to measure your heart's rhythm for a minute or longer.

 Risks

 An electrocardiogram is a completely safe and painless procedure.  In most cases, there is no reason why you should not be able to get an EKG.  The electrodes and conducting paste may feel cold when they are first applied.  You may feel a burning or stinging sensation when the area where electrodes will be placed is cleaned and shaved.  Your hair and skin may be pulled when the EKG leads are removed, which may cause some brief discomfort.

The electrodes only detect electrical impulses produced by your heart. No electricity passes through your body from the machine, and there is no danger of getting an electrical shock.

Results

The results of your test are usually available within 24 hours.  Your doctor will discuss the test results with you during a future office visit.

The information gained from this test helps your doctor make an accurate diagnosis of your condition and develop a treatment plan that's best for you.