An Internal Cardioverter Defibrillator (ICD) is a device which is implanted into the chest of some heart patients to monitor and treat abnormal heart rhythms. These devices may also be used as pacemakers, but this is not their sole function. The implantation of an ICD is only considered when it is clear that a patient may be in need of it, and the risks and benefits of the procedure are always carefully discussed with the patient before moving forward.
It can be helpful to know the difference between an ICD and a pacemaker. A pacemaker is a medical device which helps to regulate the beating of the heart with the use of electrical signals. Someone who experiences a slow heartbeat, known as bradycardia, may have a pacemaker installed to regulate their heart rhythm. An ICD responds to cardiac events such as ventricular fibrillation with a shock which is supposed to restart normal heart rhythm. In some cases, these functions are bundled into a single device.
The bulk of an ICD is taken up by a battery and a computer, attached to lead wires which run to the heart. The computer constantly monitors the patient's heart rhythm, and it is also capable of storing information which can be downloaded by medical personnel. This information can be helpful when doctors want to learn more about a patient's condition. The battery and computer are around the size of a pack of playing cards, and they are implanted under the chest muscle on the left side of the body.
When the leads tell the computer in the ICD that the heart is out of rhythm, the device responds with a electrical impulse which is designed to normalize the rhythm. The Internal Cardioverter Defibrillator may respond to problems such as tachycardia, when the heart beats too quickly, or ventricular fibrillation, in which the heart muscle loses coordination and rhythm. These conditions may require immediate medical attention, and the patient could die without an ICD, which basically acts like a medical crash team inside the body to stabilize the heart rhythm so that the patient can live to seek treatment.
The thought of an implanted medical device can be scary for some patients. However, Internal Cardioverter Defibrillators save lives, and they are very safe devices. It is possible to live a relatively normal life with an ICD, although the patient will require several weeks of recovery after surgery. It is also important to go to follow up appointments in which the effectiveness of the ICD will be tested, and some people may have to have repeat surgeries in which the battery is replaced. Patients should also be aware that the device can trigger airport security devices; it is helpful to carry a card explaining the situation, which will also be useful when you seek medical treatment.