Signal
Averaged Electrocardiogram
(SAECG)
Why is the doctor performing this procedure?
To evaluate the heart's functioning by viewing its electrical
activity. It is similar to a standard electrocardiogram (ECG),
but provides greater in-depth information by collecting many
heart beats and analyzing them together, a procedure called
signal-averaging.
What is the procedure?
Please see ECG for information on a standard electrocardiogram.
Similar to an ECG, the SAECG is a painless, non-invasive test,
with electrodes placed on the skin. These electrodes are attached
to the SAECG machine so that the electrical activity of the
heart is visualized, and then electronically manipulated by
the signal-averaging software for deeper analysis.
The Signal-Averaged Electrocardiogram essentially strengthens
some signals while eliminating "background noise"
from other signals. These signals are then filtered and averaged,
providing an analysis that yields information about patient
risk of future ventricular tachycardia (rapid heart activity)
and/or ventricular fibrillation (irregular heart activity).
These weak but very important impulses are called "late
potentials" and are commonly not evaluated in a standard
ECG. Late potentials arise from damaged or scarred areas of
heart muscle. Recognizing the presence of these late potentials
can be helpful in the following situations:
- To determine risk for ventricular
arrhythmia following heart surgery or a heart attack.
- To determine the cause of fainting
(called syncope).
- To determine if scar tissue is present from a previous
heart attack.
Where is the procedure performed?
A signal-averaged electrocardiogram can be done easily in
a number of places in the hospital (hospital room, Cath Lab).
An SAECG can also be performed in medical offices.
How long does this procedure take?
A standard ECG takes about 5 minutes; a SAECG takes a bit
longer, usually 5-20 minutes.
|
