 |
|
|
|
 Bookmark Health Information
 Make Health Information Homepage
|
 |
|
Operation
ICD insertion is considered minor surgery, and can be performed in
either an operating room or an electrophysiology laboratory. The insertion site
in the chest will be cleaned, shaved, and numbed with local anesthetic.
Generally, left-handed persons have ICDs implanted on the right side, and visa
versa, to speed return to normal activities. Two small cuts (incisions) are
made, one in the chest wall and one in a vein just under the collarbone. The
wires of the ICD are passed through the vein and attached to the inner surface
of the heart.
The other ends of the wires are connected to the main box
of the ICD, which is inserted into the tissue under the collarbone and above the
breast. Once the ICD is implanted, the physician will test it several times
before the anesthesia wears off by causing the heart to fibrillate and making
sure the ICD responds properly. The doctor then closes the incision with sutures
(stitches), staples, or surgical glue. The entire procedure takes about an hour.
Immediately following the procedure, a chest x ray will be taken to
confirm the proper placement of the wires in the heart. The ICD’s programming
may be adjusted by passing the programming wand over the chest. After the
initial operation, the physician may induce ventricular fibrillation or
ventricular tachycardia one more time prior to the patient’s discharge, although
recent studies suggest that this final test is not generally necessary. A short
stay in the hospital is usually required following ICD insertion, but this
varies with the patient’s age and condition. If there are no complications,
complete recovery from the procedure will take about four weeks. During that
time, the wires will firmly take hold where they were placed. In the meantime,
the patient should avoid heavy lifting or vigorous movements of the arm on the
side of the ICD, or else the wires may become dislodged.
After
implantation, the cardioverter-defibrillator is programmed to respond to rhythms
above the patient’s exercise heart rate. Once the device is in place, many tests
will be conducted to ensure that the device is sensing and defibrillating
properly. About 50% of patients with ICDs require a combination of drug therapy
and the ICD.
Morbidity and mortality rates
Perioperative mortality
demonstrates a 0.4–1.8% risk of death for primary non-thoracotomy implants. The
ICD showed improved survival compared to medical therapy, improving by 38% at
one year. There is a 96% survival rate at four years for those implanted with
ICD. Less then 2% of patients require termination of the device, with a return
to only medical therapy.
Normal results Ventricular tachycardia can be
successfully relieved by pacing in 96% of instances with the addition of
defibrillation converting 98% of patients to a productive rhythm that is able to
sustain cardiac output. Ventricular fibrillation is successfully converted in
98.6–98.8% of all cases. Atrial fibrillation and rapid ventricular response
leads to erroneous fibrillation in as many as 11% of patients.
Risks
Environmental conditions that can affect the functioning of the ICD after
installation include:
• strong electromagnetic fields such as those used in
arcwelding
• contact sports
• shooting a rifle from the shoulder nearest
the installation site
• cell phones used on that side of the body
•
magnetic mattress pads such as those believed to treat arthritis
• some
medical tests such as magnetic resonance imaging (MRI)
Environmental
conditions often erroneously thought to affect ICDs include:
• microwave
ovens (the waves only affect old, unshielded pacemakers and do not affect ICDs)
• airport security (although metal detector alarms could be set off, so
patients should carry a card stating they have an ICD implanted)
•
anti-theft devices in stores (although patients should avoid standing near the
devices for prolonged periods)
Patients should also be instructed to
memorize the manufacturer and make of their ICD. Although manufacturing defects
and recalls are rare, they do occur and a patient should be prepared for that
possibility.
Aftercare
In general, if the condition of the patient’s
heart, drug intake, and metabolic condition remain the same, the ICD requires
only periodic checking every two months or so for battery strength and function.
This is done by placing a special device over the ICD that allows signals to be
sent over the telephone to the doctor, a process called trans-telephonic
monitoring.
If changes in medications or physical condition occur, the
doctor can adjust the ICD settings using a programmer, which involves placing
the wand above the pacemaker and remotely changing the internal settings. One
relatively common problem is the so-called “ICD storm,” in which the machine
inappropriately interprets an arrhythmia and gives a series of shocks.
Reprogramming can sometimes help alleviate that problem. When the periodic
testing indicates that the battery is getting low, an elective ICD replacement
operation is scheduled. The entire signal generator is replaced because the
batteries are sealed within the case. The leads can often be left in place and
reattached to the new generator. Batteries usually last from four to eight
years.
Alternatives
Patients are treated with medical therapy to
reduce the chance of arrhythmia. This alternative has been shown to have a
higher rate of sudden death when compared to ICD over the initial three years of
treatment, but has not been compared at five years. If the site of ventricular
tachycardia generation can be mapped by electrophysiology studies, the aberrant
cells can be removed or destroyed. Less then 5% of patients suffer
peri-operative mortality with this cell removal.
Hit: 841 times
 Print Health Information
Health Home
| |
|
|
|
|
|
Advertise with Draligus.org