Implantable Cardioverter Defibrillator (ICD)
What is it?
An implantable cardioverter defibrillator (ICD) is an electronic device that prevents your heart from beating too quickly as a result of an abnormal heart rhythm known as a tachyarrhythmia. The ICD consists of two parts: a generator containing the battery, capacitors and electronic circuits, and one or more insulated electrodes.
The ICD monitors your heart rhythm continuously and can detect abnormal fast heart rhythms and deliver a rapid burst of impulses to your heart or a shock to bring the heart rhythm back to normal. There is also provision for stimulation of your heart to prevent abnormally slow heart rhythms as well, thus acting like a standard pacemaker.
An ICD may be implanted using general anaesthesia, or conscious sedation. Regardless do not eat or drink anything for six hours prior to the procedure. If you have diabetes, you should talk to your cardiologist about your food and insulin intake at the time of the procedure which could affect your blood sugar level. You should also discuss with your cardiologist the need to alter any other of your medications, in particular blood thinning medications such as Warfarin.
The area of the left chest wall beneath the collar bone may require skin preparation such as shaving and cleaning prior to ICD implantation. This helps prevent infection. During the procedure an ECG and blood pressure monitor will watch your heart rate and monitor, as you lie on the table in the cardiac catheterisation laboratory. Whether the procedure is performed under conscious sedation or a general anaesthetic, local anaesthetic is usually injected in the area of the operation. Antibiotics are given before and after the procedure to prevent infection.
The cardiologist makes a 5-10cm incision to create a pocket for the generator and to access a suitable vein to pass one or more electrodes into the heart using x-ray control. The cardiologist may choose to test the device during the procedure by delivering a shock to the heart and the level of your sedation will be adjusted appropriately to allow you to tolerate this. The cardiologist will then close the incision with sutures and apply a dressing directly over the area. You will then return to the hospital ward and remain in hospital overnight and the next morning a technician will check your ICD before discharge. Simple generator replacements may be done as a day case.
Risks of ICD implantation
There is a 2% chance of one or more of the following occurring during implantation:
- Collapsed lung
- Lead detachment
- Blood clots in veins
- A remote possibility of heart attack, stroke or death following the procedure
You will be instructed as to appropriate care of the wound following discharge from hospital, and the dressing will be waterproof. If you notice any problems with the healing of the wound you must contact your cardiologist immediately particularly if there is any redness, swelling or pain around the incision site, fever or ooze/bleeding from the site.
Since it takes a few weeks for the ICD electrodes to firmly attach themselves inside the heart, it is recommended that you limit arm movement on the side of the pacemaker implantation to below shoulder activities for the first two weeks.
Depending on the circumstances, you may not be allowed to drive a motor vehicle for up to six months after implantation and you should discuss this with your cardiologist.
Any electrical appliance at home that is in good working order is safe to use with your ICD. However caution should be exercised with strong magnetic fields (eg. arc welding) or unshielded ignition systems as they may activate the ICD unnecessarily or stop pacing if your heart beat is dependent on pacing from the ICD for most of the time.
The use of diathermy during surgery may affect your ICD and you should discuss any proposal for surgical operations with your cardiologist.
Mobile phones may be safely used on the opposite side of the body to the ICD.
Identification and travel
You will receive a temporary pacemaker identification card before leaving the hospital, which will be replaced by a permanent laminated card in due course. An ICD may set off security devices in airports and you should show your card to security rather than pass through the security devices, so that you can have an appropriate scan performed.