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Electrophysiology Study (EPS)
Aug 21st 2008
An electrophysiology study (EPS) is a test of your heart’s
electrical system. The indications and the types of information obtained
from an electrophysiology study vary widely.
To pump effectively the four chambers of the heart must beat in a coordinated
manner. This rhythmic contraction is very dependent on electrical
stimulation so that each chamber contracts at the appropriate time in the
cycle. When each chamber contracts is determined by the heart’s
electrical system that begins, under normal circumstances, high in the right
upper side chamber and spreads into the lower pumping chambers through a
“wiring” system made of several types of special conducting tissue.
Malfunctions in this electrical system or stimulation of the heart muscle from
abnormal wiring or tissue outside the normal conduction system lead to abnormal
heart rhythms called arrhythmia. There are many ways the electrical
system can fail and many ways the heart can be stimulated to contract
abnormally. Some of these are described in other sections
If an arrhythmia is suspected by a physician there are several tests that may
be ordered. Examples include ECGs and Holter
or event monitors. These are used to detect arrhythmias if they
occur but they give only limited information about the condition of the
conduction system or the arrhythmia if it is not recorded. An electrophysiology
study is a test that can provide very detailed information about the electrical
system of the heart not available by these more common tests. Examples of
the kinds of information an EPS can provide include details about the conduction
system such as whether it is operating normally or not, and exactly how it is
malfunctioning including where in the heart an arrhythmia starts or how it
spreads. An EPS may show exactly what type of arrhythmia may be causing
symptoms. An EPS can provide this information in several ways.
Examples include testing the normal conduction system much as an electrician
can test the wiring in a house. An EPS can discover or “map” exactly
where arrhythmias start or how they spread. In some cases, “stimulating”
the heart to “provoke” the arrhythmia can aid in diagnosis of the exact type of
arrhythmia responsible for symptoms. Sometimes provoking the arrhythmia
can provide valuable information about a patient’s risk for an arrhythmia,
particularly “life-threatening” arrhythmias. This type of information can
be very valuable in determining treatment.
An EPS is sometimes combined with a special treatment for arrhythmia called ablation.
An ablation destroys the cause of the arrhythmia and thus “cures” it.
This is described in detail in another section.
An EPS is usually performed by a cardiology sub-specialist called an
electrophysiologist. An electrophysiologist specializes in the diagnosis
and treatment of cardiac arrhythmias. Generally, the test uses one
or more special catheters that are essentially long, thin “wires” that can
record the electrical activity of the heart as well as stimulate the heart with
weak electrical impulses. These are placed inside the heart by
“threading” them through the veins. The catheters are usually introduced
into the large vein in the groin although the veins in the neck, under the
collar bone or in the arm are sometimes used. Special X-ray and
electrical recording equipment assist the electrophysiologist in placing these
catheters in the correct position inside the heart. Other special
equipment can be used to stimulate the heart or perform ablation.
In general, these studies are safe and most are
performed now on an outpatient basis. Not all arrhythmias require an EPS
for evaluation or treatment. A cardiologist or
electrophysiologist can determine whether an individual might benefit from an
EPS.
Click here to learn more about EPS.