Electrocardiogram
(ECG or EKG)
Medical Author:
Daniel Lee Kulick,
M.D.
Medical Editor:
William C. Shiel, Jr., MD, FACP, FACR
What is an electrocardiogram (ECG, EKG)?
The electrocardiogram (ECG or EKG) is a noninvasive test that is used to
reflect underlying heart conditions by measuring the electrical activity of the
heart. By positioning leads (electrical sensing devices) on the body in
standardized locations, information about many heart conditions can be learned
by looking for characteristic patterns on the EKG.
How is an ECG (EKG) performed?
EKG leads are attached to the body while the patient lies flat on a bed or
table. Leads are attached to each extremity (four total) and to six pre-defined
positions on the front of the chest. A small amount of gel is applied to the
skin, which allows the electrical impulses of the heart to be more easily
transmitted to the EKG leads. The leads are attached by small suction cups,
Velcro straps, or by small adhesive patches attached loosely to the skin. The
test takes about five minutes and is painless. In some instances, men may require
the shaving of a small amount of chest hair to obtain optimal contact between
the leads and the skin.
What is measured or can be detected on the ECG
(EKG)?
- The underlying rate and rhythm mechanism of the heart.
- The orientation of the heart (how it is placed) in the chest cavity.
- Evidence of increased thickness (hypertrophy) of the heart muscle.
- Evidence of damage to the various parts of the heart muscle.
- Evidence of acutely impaired blood flow to the heart muscle.
- Patterns of abnormal electric activity that may predispose the patient to
abnormal cardiac rhythm disturbances.
When is an ECG (EKG) performed?
- As part of a routine physical examination or screening evaluation.
- As part of a cardiac exercise stress test.
- As part of the evaluation of symptoms of chest pain, shortness of breath, dizziness or fainting, palpitations, or
- As part of the preoperative workup for surgery in patients who may be at an age where heart disease could potentially be present.
Next: What conditions may be diagnosed with an ECG (EKG)? »
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