Electrophysiology Procedures
Patients who experience or are
at risk for abnormal heart rhythms, called
arrhythmias, may need an electrophysiology
diagnostic procedure. This brochure outlines
some of the tests and procedures for heart
arrhythmias.
The heart is the body's pump, but it has its own
electrical system that causes the heart to
contract to pump blood and oxygen to the body.
An electrophysiologist is a cardiologist that
specializes in heart arrhythmias.
Arrhythmias can include problems that cause the
heart to beat too quickly (tachycardia), too
slowly (bradycardia) or with irregularity.
Sometimes these rhythms are felt as palpitations
by the patient.
Electrophysiology (EP) Study
An electrophysiology (EP) study is an invasive
diagnostic test to evaluate the electrical
system of the heart. The EP study is usually an
outpatient procedure and can last between one to
two hours. The patient will be under the care of
a highly skilled team including the
electrophysiologist, nurses, technicians and
physician assistants.
Prior to the procedure intravenous (IV) sedation
is given. It is not general anesthesia, but it
will make the patient sleepy during the
procedure. The patient may be somewhat aware of
what is going on, but it is rare to feel any
discomfort during the procedure. There will be
many monitors surrounding the patient as well as
several EKG leads and patches which are placed
on the chest, legs and back. During the
procedure, the electrophysiologist will insert
special electrode catheters (thin flexible
wires) through a large vein in the groin. The
area is cleaned and numbed with a local
anesthetic before a puncture is made for the
catheter insertions. The catheters are advanced
into the heart to record and measure the
electrical signals. Fluoroscopy, a special type
of X-ray, will help the physician place the
wires in the heart. During the study, the heart
will be paced in various ways to test for
arrhythmias. Some-times IV medication is
administered to test the heart as well.
An EP study is considered relatively safe, but
it is an invasive procedure that involves some
risk. Risk includes swelling or bruising at the
insertion site. Less frequently, there may be
damage to the heart or blood vessels, formation
of blood clots (deep vein thrombosis, pulmonary
emboli), significant bleeding or infection.
Deaths are extremely rare.
Most patients can go home on the same day the EP
study is peformed. However, patients should not
drive for 24 hours after the procedure and
should avoid strenuous activity for two to three
days.
Radiofrequency Ablation
During an EP
study, sometimes an arrhythmia is found that can
often be cured by radiofrequency (RF) ablation.
Often patients are diagnosed with an arrhythmia
prior to EP studies. RF ablation is often
offered to patients who experience side effects
or recurrent symptoms on medication.
During the EP study, a special catheter is used
that delivers radiofrequency energy to the area
of the heart causing the arrhythmia. The
radiofrequency energy heats up the tissue in
contact with the catheter and destroys the
tissue causing the arrhythmia. The success rate
of RF ablation depends upon the type and nature
of the arrhythmia as well as the patient's
overall heart condition. RF ablation has a 98%
success rate for many supraventricular
arrhythmias.
The procedure itself is similar to the EP study.
RF ablation can take longer, sometimes several
hours, to allow for detailed electrical
"mapping" or identification of the area to be
ablated. Also, the electrophysiologist will need
to retest the heart to see if the arrhythmia can
be induced again after ablation has been
performed. Many patients go home the same day,
but occasionally some patients may have to stay
overnight.
Risks are similar to those of the EP study and
include swelling or bruising at the insertion
site. Less frequently, there may be damage to
the heart or blood vessels, formation of blood
clots (deep vein thrombosis, pulmonary emboli),
significant bleeding or infection. With
ablation, there is also a small risk of damaging
the normal electrical system of the heart, which
would require implantation of a pacemaker.
Deaths are extremely rare.
Tilt Table Testing
For patients
with syncope, or fainting, a tilt table study
may be recommended. This test is done for
patients who may have problems regulating their
blood pressure or pulse in response to changes
in body position.
Syncope is often caused by an abnormal reflex
involving blood vessel dilation and signals to
the heart.
Prior to the test, an IV line is inserted. The
patient is then continuously monitored for
changes in heart rate or rhythm and blood
pressure. The patient is placed on a table and
secured in case of fainting. The table is tilted
60 to 80 degrees upright and the patient is
monitored for up to 40 minutes. A medication may
be used during testing to stimulate the
patient's abnormal reflex. The patient's
response to tilt table testing, including
symptoms of fainting, EKG strips and blood
pressure response, will determine further
therapy.
Treatments
Once the
patient has been diagnosed using EKGs, an EP
study or a tilt table test, the treatment may
include one of the following.
-
Medications called
antiarrhythmics can be prescribed to help
regulate the heart rhythm which can promote
more efficient pumping of the heart.
Anticoagulants like Coumadin (warfarin) or
aspirin may also be necessary to reduce risk
of clot formation or stroke.
-
Electrical cardioversion may
be recommended for heart arrhythmias like
atrial flutter or atrial fibrillation. This
is when an electrical shock is given,
usually across the chest wall, to reset the
heart rhythm.
-
Implantable pacemakers can
be recommended for patients with slow heart
rhythms, or bradycardia.
-
Implantable Cardioverter
Defibrillators (ICDs) can also be
recommended for patients at risk for life
threatening arrhythmias. The ICD uses an
electrical shock to convert the patient's
heart rhythm.
