Ordinarily, your heart beats at a regular,
steady pace called a normal sinus rhythm that is regulated electrically
by the sinus node. However, if certain cells in the lower chamber
of your heart (the ventricles) begin to generate their own electrical
impulses, these can override the heart's normal electrical control
mechanism. These impulses do not follow the heart's normal conduction
pathway, and may prevent the heart from pumping enough blood and
oxygen through the body. One situation, called ventricular tachycardia
(VT), may cause you to feel fluttering in the chest or throat
or a sensation of "skipped" heartbeats.
Because less blood is pumped with each beat,
your body and brain receive less oxygen-carrying blood, which
may result in dizziness, blackouts or fainting, and even unconsciousness.
Sometimes VT can be prevented or treated with medications. In
other cases, an electrical device is needed to deliver an impulse
to the heart to stop the arrhythmia.
When the ventricular arrhythmia becomes even
more rapid and unstable, it causes a condition called ventricular
fibrillation (VF) — the heart is quivering, and no longer
pumps any blood. This leads to cardiac arrest. The only way to
correct ventricular fibrillation is to quickly deliver a strong
electrical shock to the heart to stop the abnormal rhythm and
prompt the heart's normal electrical conduction system to take
over again. This process is called defibrillation.
Your Implantable
Cardioverter-Defibrillator
In a hospital or ambulance, when emergencies
cause life-threatening arrhythmias, defibrillation is done with
an external device called a defibrillator. Paddles are placed
against the chest, and a strong electrical impulse is delivered
through the heart. However, if your arrhythmia (either ventricular
tachycardia or fibrillation) occurs in routine situations, an
implantable cardioverter-defibrillator (ICD) can be implanted
to monitor and deliver whatever therapy is necessary. It will
be programmed to detect and diagnose either ventricular tachycardia
or ventricular fibrillation, and will deliver the therapy necessary
to correct your abnormal heart rhythms.
Your physician may choose to implant a defibrillator
in your body to monitor your heart rhythm around the clock and
to immediately correct any dangerous arrhythmias should they occur.
The ICD has two components: the generator
and the lead(s). The generator is a small, flat, lightweight case
that holds a tiny computer and battery. This will generate the
electrical impulses used to regulate your heartbeat. The leads
are wires covered with soft, flexible plastic. They are connected
to the generator and "tell" it how the heart is beating. The leads
also transmit the electrical impulses from the generator to the
heart.
Preparation
Your cardiologist or one of the cardiology
nurses will discuss the procedure — its purpose, benefits,
and potential risks — before you receive your ICD.
Inserting an ICD is a common, low-risk surgical
procedure with a very small risk of complications. These may include:
puncture of the heart or lung tissue, damage to
the vein, infection, bleeding and/or bruising, or other uncommon
events. You'll be asked to sign a surgical consent form before
you have this procedure. If you have any questions or concerns,
be sure to discuss them with your cardiologist.
Your physician will also order a series of
tests prior to your ICD. These will include an electrocardiogram
(ECG) and some blood tests. They will also go over all medications
you're currently taking and give you any special instructions
concerning them.
Procedure
Usually you'll be instructed not to eat or
drink anything after midnight the evening before your procedure.
You may, however, take sips of water to swallow pills. If you're
coming to the hospital as an outpatient, you'll be told where
and when to report. You should plan for an overnight stay and
arrange for someone to drive you home.
Just prior to the procedure, an intravenous
line (IV) will be inserted into your arm to administer any necessary
medication, including a sedative to help you relax. The area where
the ICD will be inserted will be washed with an antiseptic and
shaved, if necessary. Then, you'll be moved by stretcher or wheelchair
to an electrophysiology (EP) laboratory where you'll be positioned
on a special table and covered with sterile drapes. The entire
EP staff, who have been trained specifically in the electrical
activity of your heart, will be wearing surgical hats and masks
to assure that everything remains sterile throughout your procedure.
As the procedure begins, you'll receive an
injection to numb the ICD insertion site. A small incision will
be made, and a small "pocket" formed under the skin in your upper
chest. Then a lead will be threaded into the vein that runs just
below the collarbone. This lead will be guided into your heart
using an x-ray monitor.
Once in place, it will be tested to make sure
it's in the best possible position. Then, it will be attached
to the ICD generator, which will be placed in the pocket under
your skin. At this point, you'll be given some medication through
the IV that will put you to sleep for a few minutes. While you're
asleep, the ICD will be tested to be certain it is functioning
properly.
When your cardiac team is certain your ICD is securely in position and will do its job well, your incision will be sutured (stitched) and covered with a small bandage. Throughout the entire procedure, which takes about one to two hours, your ECG, heart rate, blood pressure, and oxygen level will be constantly observed on monitors in the laboratory.
Although you'll feel some pushing and tugging
on your skin at times, there should be little or no discomfort
during the procedure. If you feel any discomfort, tell the physician
or staff immediately.
Your Recovery
After your procedure, you'll be taken to a
hospital room or recovery area. You will be kept overnight in
the hospital so that your heart can be monitored to be certain
the ICD continues to function properly. You'll be asked to limit
the use of your arm on the side the ICD was inserted. This gives
the lead a chance to begin "healing" into your heart.
If you begin to feel some discomfort in the
incision area when the local anesthetic wears off, let the staff
know and they'll give you some medication to help make you more
comfortable. Be sure to tell your nurse if you experience any
unusual symptoms such as hiccups, dizziness, or chest pain.
Make sure you arrange for someone to drive
you home when you are discharged. Before you leave the hospital,
you'll be given detailed instructions about caring for the incision
site. Your physician will also explain follow-up plans, and discuss
what signs and symptoms should be reported.
Your Good Health
Your ICD will help your heart beat maintain
the regular rhythms necessary to pump oxygen-rich blood throughout
your body. However, you also play an important role in staying
healthy. Be sure to keep all appointments for exams and follow-up
tests. Follow your instructions, don't hesitate to talk about
your concerns.
As always, if you have any questions about
your health, be sure to ask your physician.
If you are a Munson Healthcare patient and have a compliment,
concern, or complaint, please contact one of our Patient
Liaisons.
