An electrogram ( EGM) is a recording of Action potential of organs such as the brain and heart, measured by monitoring changes in Voltage.
Brain
Electroencephalography (EEG)
An electroencephalogram (EEG) is an electrical recording of the activity of the brain taken from the
scalp.
An EEG can be used to diagnose
Seizure,
Sleep disorder, and for monitoring of level of anesthesia during surgery.
Electrocorticography (ECoG or iEEG)
An electrocorticogram is an electrical recording of the brain measured intracranially, that is, from within the brain.
Eye
Electrooculography (EOG)
An electrooculogram (EOG) is an electrical recording of the potential between the
cornea and the
retina, and does not change with visual stimuli.
An EOG can measure movements of the eyes and can help in diagnosis of
nystagmus.
Electroretinography (ERG)
An electroretinogram (ERG) is an electrical recording of the electrical activity of the retina.
Heart
Electrocardiogram (ECG)
An electrocardiogram (ECG or EKG) is an electrical recording of the activity of the heart.
The typical meaning of an "ECG" is the 12-lead ECG that uses 10 wires or
Electrode to record the signal across the chest.
Interpretation of an ECG is the basis of a number of cardiac diseases including myocardial infarction (heart attack) and arrhythmias such as atrial fibrillation.
Cardiac electrogram
When electrical recordings are made from the
skin, it is considered to be an ECG as described above.
However, electrical recordings made from within the heart such as with an artificial cardiac pacemaker or during an electrophysiology study, the signals recorded are considered an "electrogram" instead of an ECG.
These signals are not interpreted in the same manner as an ECG.
Other muscles
An electromyogram (EMG) is an electrical recording of the activity of a
Muscular system or muscle group.
An EMG study can be combined with a nerve conduction study to diagnose neuromuscular diseases such as peripheral neuropathy and amyotrophic lateral sclerosis.
See also
Further reading
