IMPLANTABLE CARDIOVERTER DEFIBRILLATOR
Introduction
Your doctor has recommended an
Implantable Cardioverter
Defibrillator (ICD) to treat your
rapid heart rhythms. This
information sheet aims to provide
you with knowledge about the
procedure of implanting an ICD, how
an ICD works to treat your rapid
rhythms, how an ICD may affect
your life and what precautions you
need to take after you receive your
ICD.
The information sheet answers
many questions commonly asked by
people who have an ICD and their
families. It gives general
information about your ICD. You
should always talk to your doctor
about your specific condition and
any special precautions you should
take. If you find information in here
that differs from what your doctor
has told you, always follow your
doctors’ instructions and discuss this
with your doctor at your next
appointment.
Normal Electrical Conduction
Pathways in the Heart
Your heart is a muscle that pumps
blood throughout your body sending
oxygen enriched blood and
nourishment to all of your body
cells.
The heart consists of four chambers
and is split into the left and right
sides of the atria (top half) and
ventricles (bottom half). Your heart
rate is generally controlled by a
discrete, specialised group of heart
cells called pacemaker cells. These
pacemaker cells are in turn
controlled by your brain and
numerous other factors.
The pacemaker cells that control
your heart are located in the very
top of the right atrium in an area
called the sinus node.
Functionally, the atria act as
reservoirs/ priming chambers for
the ventricles.
From the sinus node the electrical
signals spread through the atria and
meet another group of specialised
cells between the atria and
ventricles. This is called the atrioventricular node (AV node).
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PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.
the heart is pounding or skipping
beats.
From the AV node the electrical
impulses pass through to the
ventricles which are the main
pumping chambers.
As long as the electrical impulses
travel at regular intervals, your
heart will beat at a steady rhythmic
pace. The rate will vary depending
on your level of activity.
As the heart pumps faster it pumps
less blood. The electrical signal
does not run through the heart
normally, and the heart may not
contract efficiently. The ventricles
may not have enough time to fill
with blood between each
contraction because this is
happening so quickly. Less blood is
pumped to the brain and if this
rapid heart beat continues, the
brain and body may not receive
enough blood and oxygen. You may
then feel dizzy and even pass out.
VT can be dangerous, even life
threatening, if not properly treated.
Rapid heart rhythms
Another type of tachyarrhythmia is
ventricular fibrillation (VF). During
VF there are several electrical
impulses being generated from
within the ventricles and several
areas of the heart muscle are
contracting in a disorganised and
erratic manner. The heart muscle
quivers and your heart no longer
pumps any blood at all. Your body
quickly becomes starved of oxygen
and you usually pass out within a
few seconds. This situation is called
cardiac arrest.
Sometimes things go wrong in the
heart’s electrical system causing an
abnormal, often irregular heart beat
called an arrhythmia. When the
heart beat is too fast it is called a
tachyarrhythmia. When this
electrical impulse has started in the
lower chambers of your heart (the
ventricles), instead of the sinus
node, the heart rhythm is called
ventricular tachycardia (VT). The
fast heart rate might feel as though
Emergency teams try to revive
people from cardiac arrest by using
machines called defibrillators to
send electrical impulses or shocks
through the heart. This is done by
passing an electrical current
through two paddles of the
defibrillator held externally on to
the chest. The electrical current or
shock from the defibrillator passes
through the heart, stops the erratic
Your heart usually beats regularly
between 60 to 100 beats per
minute. It may beat faster than this
if you are exercising or doing
something very active and it may
beat slower than this if you are
asleep, resting or on medication.
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PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.
electrical activity, and allows the
heart to return to a more regular
rhythm.
This emergency treatment is more
likely to be effective if it is given
quickly as the cells in the brain and
body tissues will begin to die within
minutes if they do not receive
oxygen. Your ICD is an internal
defibrillator and pacemaker. When
your heart goes into a
tachyarrhythmia, the defibrillator
can pace or shock your heart out of
VT or VF within those first crucial
seconds.
What is an ICD and how does
it work?
An ICD consists of a pulse generator
and leads. The pulse generator or
defibrillator is like a small computer
(microprocessor) that runs on a
battery. The battery and circuitry
are sealed inside a titanium case.
Slow heart rhythms
Sometimes the heart beats too
slowly. This is called bradycardia.
This can be caused by the sinus
node not working properly or by a
condition called heart block. Heart
block is when the sinus node sends
out an electrical impulse but it is
delayed or interrupted along the
normal electrical pathways in the
heart and may not reach the
ventricles at all. Bradycardia may
persist or it may only occur
occasionally. Some medications
that are used to treat
tachyarrhythmias may cause the
heart to beat too slowly at times.
During bradycardia, the heart may
beat so slowly that the body and
brain may not receive enough
oxygen. A person with bradycardia
may feel tired or may have
blackouts.
The leads are insulated wires that
connect the defibrillator to your
heart. There are 3 types of ICDs
according to the number of leads.
The type of ICD you receive depends
on your specific requirements.
Single chamber ICD
A single chamber ICD uses one
defibrillation lead, placed in the
right ventricle to sense, pace and if
necessary shock the heart.
Dual chamber ICD
A dual chamber ICD has two leads, a
pacing lead in the right atrium to
pace and sense, and a defibrillation
lead (to sense, pace and if
necessary shock the heart)
in the right ventricle.
www.qcg.com.au
PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.
Bi-Ventricular ICD
A bi-ventricular ICD has three leads,
a pacing lead in the right atrium, a
defibrillation lead (to sense, pace
and if necessary shock the heart) in
the right ventricle and a pacing lead
placed within a vein that lies on the
outside surface of the left ventricle.
your arrhythmia. There are three
ways the ICD may respond: pacing,
cardioversion and defibrillation.
Pacing
This may be used to treat slow or
fast rhythms. If your heart beats
too slowly (below a limit set by your
doctor) the ICD will detect this and
will deliver pacing impulses to
stimulate your heart. It will
continue to do this until your heart
starts to beat at a normal rate on its
own.
Your doctor may also program your
ICD to deliver a rapid sequence of
pacing impulses as the first step in
the treatment of your VT. If normal
rhythm is restored no further
treatment is delivered.
Programmer
A programmer is a machine that is
kept by your doctor and
communicates with your ICD via
radiofrequency waves. It is used to
program the settings of your ICD so
that it is fine-tuned to your specific
needs. The programmer also reads
information contained in the ICD.
Detailed data (including date and
time) is provided by
the ICD
regarding any
rapid
rhythms
you have
had and how
they were
treated by the
device.
Cardioversion
If pacing does not stop the
arrhythmia, the ICD will deliver the
next therapy – cardioversion. This
involves delivering stronger
electrical impulses to the heart
muscle.
Cardioversion shocks may progress
from low energy to high energy as
needed.
Defibrillation
This is similar to cardioversion, but
it delivers a stronger high energy
shock to your heart. This is used
when pacing and cardioversion have
not been successful in treating VT
and is always used first to treat VF.
The defibrillator continually
monitors your heart rhythm. It has
been programmed by your doctor to
respond in specific ways to treat
www.qcg.com.au
PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.
What do the treatments feel
like?
Pacing
Most people do not feel these
impulses and may not be aware that
it is occurring. If the pacing is to
treat a tachyarrhythmia you may
feel a slight fluttering in your heart.
Clinical data suggest that about 90%
of VTs are stopped by pacing.
Cardioversion
Most people say this is mildly
uncomfortable and describe it as a
sharp thump in the chest.
Defibrillation
After the leads are in position they
are secured and connected to the
pulse generator which is positioned
on the left side of your upper chest.
During the procedure the ICD is
tested to ensure it can detect and
successfully treat VF. During this
time you will be given a light
anesthetic.
Often the person has lost
consciousness when this therapy is
delivered so they are not aware of it
occurring. People who have
experienced a defibrillation shock
whilst conscious describe it feeling
like a “kick in the chest”. They say
it startles them and is distressing
but only lasts for a second.
Your preparation will include
performance of some test to gather
information about your heart
rhythms. You may have already had
these prior to admission.
How is the ICD implanted?
THE PROCEDURE
The procedure is performed in the
Cardiac Catheter Theatre where the
ICD leads are implanted
transvenously. The leads are
introduced into a vein in the left
upper chest region. The lead is
then threaded through the vein to
the appropriate chamber in the
heart.
These tests may include:
• Electrocardiograph
• Blood tests
• Electrophysiology study (EPS)
¾
Before the procedure
Ask any questions regarding your
uncertainties
When you are admitted to the ward
you will be asked to:
• Have nothing to eat for 6 hours
before the test.
• You may be required to have
blood tests and an
electrocardiogram (ECG).
• Male patients will require a
chest shave.
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PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.
•
•
•
Have an antiseptic shower
Have a needle (IVC) inserted into
an arm vein connected with an
IV line to a bag of fluid (drip).
Before the procedure you will
receive a tablet to help you
relax.
¾ After the procedure
The procedure should take
approximately 2 hours.
On return to the ward you will be
monitored overnight and will remain
resting in bed until next morning.
The morning of discharge
Your ICD will be tested the next
morning by your doctor or a
pacemaker technician. The
monitoring leads will be removed
once your CRT device has been
checked. You may still experience
some pain at the insertion site.
This should be eased by taking some
paracetamol
By the time you go home you will
have had a number of tests, spent
some time in hospital and
undergone a surgical procedure to
have your ICD implanted. This may
leave you feeling emotionally and
physically drained and perhaps
depressed. This is quite normal and
will improve as you recover. Most
people adapt very well to their ICD
and return to most of their previous
activities.
How will the ICD affect my
life?
Activities
Your doctor
will give you
advice on
what you
should and
should not do
when you
return home.
Once you
have fully recovered you should be
able to confidently resume your
normal activities of daily life. You
can safely use common household
appliances including microwave
ovens, televisions, video and
computer games, gardening
machinery and portable phones etc.
Depending on your condition your
doctor may ask you to avoid
activities during which a few
seconds of unconsciousness could be
dangerous to you or to others.
These may include driving,
swimming, climbing a ladder or
boating alone.
Precautions
Identification card
You will receive a booklet produced
by the manufacturer of the ICD
along with an ICD identification
card. Always carry your ID card
with you to alert medical and
security personnel that you have an
implanted device. Your ID card
provides information that may be
needed if you require emergency
treatment.
www.qcg.com.au
PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.
Medications
Although your ICD may replace some
medications you may still need to
continue with others. Some
medications work with your ICD to
treat abnormal rhythms and other
may be necessary to treat other
medical conditions. Make sure you
understand why you are taking
these medications and always take
them as directed by your doctor.
Avoid
Avoid strong electric or magnetic
fields which may interfere with the
ICDs function.
Observe all warning notices
addressed to people with
pacemakers.
Probable sources of electrical
interference include:
Airport screening devices
Airport screening devices may
detect the pacemaker’s metal case.
It will be necessary to present your
pacemaker card to obtain
clearance.
•
Household appliances
ICDs are protected from most
interference produced by electrical
appliances.
You can safely use common
household appliances if it has been
properly grounded and maintained
in good repair. This includes
microwave ovens, televisions, video
and computer games, gardening
machinery and portable phones etc.
An electrical current from poorly
grounded equipment could cause
your ICD to deliver a shock even if
the current is too small to be
noticed.
Take normal precautions especially
when using electrical equipment in
damp or wet conditions. If you feel
a tingle when touching anything
metal such as an electrical
appliance immediately let go and
have the cause investigated and
corrected by a qualified person.
•
•
•
•
•
•
•
•
Magnetic underlays used to
alleviate the pain of arthritis.
Mobile phones – use on the
opposite ear to the side of the
ICD.
MRI scanners.
TENS machines used by
physiotherapists.
Electrical arc welding
equipment.
Dielectric heaters used in
industry to bend plastic.
Electric steel furnaces.
CB radio antennas.
Some battery powered tools.
Medical procedures
Always tell any health professional
that you have an ICD and show your
ID card. Most medical procedures
are unlikely to interfere with your
pacemaker except MRI scanners.
Mobile Phones
Studies have indicated that there
may be some potential interaction
between mobile phones and ICDs.
This may be due either to the
radiofrequency signal or the magnet
housed within the phone. The
effect is temporary and may include
preventing or delivering an extra
therapy when the phone is within close
proximity (15 cm/6 inches).
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PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.
•
•
•
Maintain a minimum distance of 15
cm between your device and a
hand-held mobile phone.
Hold the phone to the ear opposite
your device.
Don’t carry your phone in your
breast pocket.
Follow up visits
An important feature of your ICD is
the information that it stores about
your heart function between each
visit. This information is accessed
at your follow up and assists your
doctor in your ongoing treatment.
A typical follow up visit may last
about 20 minutes. During this time
a pacemaker programmer (which
looks like a lap top computer) will
enable your doctor and the
pacemaker technician to “talk” to
your pacemaker.
Information gathered may include:
• How your device has performed
since your last visit.
• Any irregular heart rhythms or
events that may have occurred.
• Any events that may have
occurred. You may wish to keep
a diary of any times you think
the device may have been used.
Your responsibilities
Your ICD will monitor and treat your
heart automatically. But you must
make an effort to follow your
doctor’s instructions and keep
follow up appointments.
At these check ups your doctor will
also ensure that your ICD is
functioning correctly and that the
device is programmed to suit your
individual needs.
You should:
Ask your doctor or nurse any
questions about anything you are
unsure of.
Take medications as prescribed by
your doctor.
Carry your ID card with you at all
times.
Inform your family doctor, your
dentist and emergency personnel
that you have an ICD device.
Your follow up appointments take
place at regular routine check-ups
that will be scheduled; the first
after 3 months and then 6 monthly
thereafter.
www.qcg.com.au
PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.
Who do I call?
What your friends and
family should know
Phone your cardiologist during
office hours if you:
•
•
•
•
•
Notice any redness, swelling,
warmth or fluid drainage from
your wound site.
Develop a fever that does not go
away after 2-3 days.
Have any questions about your
CRT device, heart rhythm or
medications.
Plan to travel or move.
Notice anything unusual or
unexpected such as new
symptoms.
For patients with a CRT - ICD
device:
Your friends and family should be
encouraged to learn about your CRT
device and how they can continue
to support you at home. You may
all need time to adjust to living
with your defibrillator. Your device
can be a source of security for you
and your family and can be viewed
as a positive development. This will
help you all to be more comfortable
with your device when you are away
from emergency care. Some friends
or family members may want to
learn more about cardiopulmonary
resuscitation (CPR). They can
contact the local ambulance service
or St John’s ambulance service for
more information.
What to do if you receive a
shock from your CRT - ICD?
1. Stay calm.
2. Move to a comfortable place
where you can lie or sit down.
3. One shock from your ICD providing you are feeling OK there
may not be any need for immediate
medical assistance.
4. If you receive a series of shocks
or symptoms persist - call an
ambulance Dial 000
5. If you receive more than
one shock in 24hrs or have
repeated shocks notify your
cardiologist.
www.qcg.com.au
PO Box 525 · Spring Hill, Qld 4004 · 07-3839-0677 · Fax: 07-3016-1199 · [email protected]
This information is not intended to cover all aspects of any medical condition. It is generalized and is not intended as specific medical advice. Those with
questions or need more information should check with their physician. Copyright ©2005 Queensland Cardiovascular Group. All rights reserved.