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Defibrillator (ICD)
An implantable cardioverter defibrillator (ICD) continuously checks the heart's rhythm. It can deliver electrical treatment if the lower chambers develop a dangerous rhythm that stops the heart pumping properly.
An ICD is a small, battery-powered device placed under the skin of the chest. It detects dangerous rhythms in the ventricles, the heart's lower pumping chambers. These include ventricular tachycardia, when the chambers beat very fast, and ventricular fibrillation, when they quiver rather than pump. Either rhythm can lead to cardiac arrest, when the heart stops pumping effectively.
The ICD receives electrical signals through thin wires called leads. Its battery and electronic circuits sit inside a casing called the generator. The doctor programs the device to recognise the rhythms that need treatment and respond automatically.
Some ICDs can first send a short burst of small, rapid pacing pulses to interrupt certain fast rhythms. If that doesn't work, or the rhythm needs shock treatment, the device delivers a stronger electrical shock. Stopping the dangerous rhythm can let the heart pump effectively again and can save a life.
An ICD treats these rhythms after they start. The underlying heart condition is still there, so medicines and other heart care remain important.
Call triple zero (000) for severe, worsening or persistent chest pain, or chest discomfort with breathlessness, sweating, nausea or pain spreading to your arm, jaw or back.
Do not wait for a routine appointment or drive yourself to hospital.
The hospital gives you instructions about eating, drinking and medicines. Check these in advance, particularly if you take blood thinners or diabetes medicines. Plan for someone to take you home.
For a transvenous ICD, local anaesthetic numbs the area below the collarbone. Sedation makes you relaxed and drowsy, although you may remain aware of what's happening. Some procedures use a general anaesthetic, so you're asleep.
The doctor makes a small cut, guides the leads through a vein into the heart and secures their ends to the heart muscle. The leads connect to the generator, which sits in a pocket under the skin. The device is tested and programmed before the wound is closed, and the generator and leads stay in place. An S-ICD is placed under the skin of the chest instead, and no leads enter the heart.
Bruising, soreness and bleeding around the wound can occur. Other risks include infection, a lead moving or device failure requiring further treatment. Serious complications can include a punctured lung or injury to the heart or blood vessels, depending on the procedure. An ICD can sometimes give a shock for a rhythm that doesn't need one.
An ICD may be recommended after a cardiac arrest caused by a dangerous ventricular rhythm, or after another serious episode of ventricular tachycardia.
It may also be offered before an episode occurs. That can apply to people whose heart remains significantly weakened despite treatment, or who have certain inherited heart conditions. In heart failure, a scan showing persistently reduced pumping strength is one of the findings doctors use when considering an ICD.
The cardiologist considers the heart's pumping strength alongside rhythm recordings, the underlying condition and your overall health. Having heart failure or an irregular heartbeat doesn't automatically mean you need an ICD.
A transvenous ICD has one or more leads that pass through a vein into the heart, where they sense the rhythm and deliver treatment. As well as shocks, this type can provide pacing for a slow heartbeat and rapid-pulse treatment for certain fast rhythms.
A subcutaneous ICD, or S-ICD, has its generator at the side of the chest and a lead under the skin near the breastbone. The lead stays outside the heart and blood vessels. The S-ICD can deliver shocks, but it doesn't provide ongoing pacing or rapid-pulse treatment. Whether you need either of those affects which device is suitable.
Some people with heart failure also need pacing to help the lower chambers beat together. A device combining this treatment with a defibrillator is called CRT-D.
An ordinary pacemaker mainly treats a heartbeat that's too slow and doesn't provide the shock treatment of an ICD.
You'll recover under observation in hospital, with a dressing over the wound. Before discharge, you'll receive instructions about wound care, arm movement and returning to activity. Contact the treating hospital if the wound becomes red, swollen or leaks fluid, or you develop a fever.
Device checks read the battery status, lead function and recorded rhythms and treatments without surgery. Some are done through a home monitor that sends information to the device clinic, but this isn't an emergency response service. As the battery runs low, replacement can be planned before it runs out. The generator is replaced, while working leads can usually stay.
Keep your device identification card and the device clinic's contact details. Contact the clinic if the ICD beeps or gives an alert.
Rapid pacing pulses usually cause little or no discomfort. A shock is brief but can be painful or very uncomfortable. The rhythm itself may cause dizziness or palpitations before treatment. If it causes a blackout, you may not feel the shock.
Before going home, get a written shock plan with after-hours contact numbers. After a shock, if you feel well, follow the plan and contact the device clinic. If you're dizzy or unwell, get medical advice straight away. Repeated shocks need urgent medical attention even if you feel well. Call triple zero (000) after a shock if you have chest pain, severe breathlessness, collapse or feel seriously unwell. Don't drive yourself.
Driving restrictions depend on why the ICD was fitted and any further rhythms or shocks. Get individual advice about when you can drive again, especially if you drive for work. Most ordinary household equipment can be used. Keep phones and magnets away from the implant, and check with the device clinic about work involving strong magnets or electrical fields.
Your GP or specialist can refer you to a Heartscope cardiologist to discuss your heart condition and whether referral for an ICD is appropriate. Implantation takes place in hospital, not at a Heartscope clinic. The clinic can answer questions about the consultation and what information to bring.
Consultations are privately billed. If you're eligible, Medicare pays part of the consultation fee when you have a valid referral from your GP or specialist. The clinic will confirm the amount left to pay before the visit.
Hospital and procedure fees are separate from the consultation fee. The hospital or treating provider confirms those costs.
Heartscope cardiologists see patients at clinics in Melbourne and Queensland. If you have a referral, our team can confirm the location and appointment details.
View clinic locationsNo. ICDs are implanted in hospital. Heartscope's cardiologists may be able to see patients with a valid referral from their GP or specialist, and can refer them for hospital treatment when appropriate.
It may be possible, but the MRI service and device clinic need to check the exact generator and leads, and plan changes to the settings and monitoring. Tell the imaging service about your ICD before the scan.
If worry is affecting your sleep or keeping you from everyday activities, tell your GP or device clinic. A review can go through your concerns about the device and put you in touch with support for anxiety. You don't have to wait until a shock happens.
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