An electrocardiogram, abbreviated as ECG or sometimes as EKG, is a graphic record of the heart's electrical activity. Healthcare professionals use it to help diagnose heart disease. They can also use it to monitor how well different heart medications are working.
Who is a candidate for the test?
An ECG is done on a person to help diagnose heart disease. It may also be used to monitor how well different heart medications are working. Persons coming into the emergency room with chest pain, shortness of breath need to have an ECG performed. An ECG may be necessary as a baseline tracing before a person has major surgery, in case arrhythmias develop later.
How is the test performed?
A person can have an ECG while either lying down or exercising on a treadmill. A technician uses an adhesive to attach approximately 12 to 15 electrodes at specific sites on the skin. These sites are selected on both arms and on the chest. The sites are cleaned and perhaps shaved before the electrodes are attached. A machine then records the electrical activity of the heart under conditions a healthcare professional has specified. An ECG usually takes about 5 minutes to perform.
What is involved in preparation for the test?
Individuals will be given specific instructions by their healthcare professional if necessary.
What do the test results mean?
Normal results include the following:
- a heart rate that is between 50 and 100 beats per minute
- a consistent and even rhythm
- a pattern on the graph that corresponds to pattern profiles established for healthy people
Abnormal results can come from any of the following:
- a muscle defect
- an enlargement of the heart
- defects from birth
- heart-valve disease
- abnormal rhythms (arrhythmias), including tachycardia, a heartbeat that is too fast, or bradycardia, a heartbeat that is too slow
- coronary artery disease
- an inflammation of the heart
- an altered electrolyte balance (including potassium or sodium abnormalities)
- a past heart attack, one that is happening at the moment, or one that is about to happen