An implantable cardioverter defibrillator (ICD) is an implanted device that can restore normal heart rhythm. Like a pacemaker and slightly bigger, an ICD is implanted under the skin, just under the clavicle (collarbone). Electrodes within designated areas of the heart are attached to wires, which lead back to the ICD. Your physician will program your ICD to meet your specific needs. If a dangerous heart rhythm is detected, the defibrillator can either overdrive pace the arrhythmia or, if necessary, deliver an internal energy shock to restore normal heart rhythm. In addition, the device tracks heart rate and rhythm activity and stores information about your heart’s rhythm for your physician to review.
An ICD responds to abnormal coronary electrical activity and can deliver three distinct levels of therapy to restore a normal heartbeat. These levels are:
- Anti-tachycardia pacing When the ICD senses that a heartbeat is irregular or too rapid, it emits low-energy, regular impulses to capture the heart rate and rhythm and overdrive terminated the arrhythmia. The use of these low-energy impulses is called anti-tachycardia pacing (ATP) and people with an ICD are rarely aware of these impulses.
- Cardioversion /Defibrillation: This therapy involves delivering a programmed electric shock to convert the arrhythmia to normal rhythm. This therapy is used when either anti-tachycardia pacing fails or the arrhythmia is determined to be too dangerous to wait for other attempts at conversion. You may feel a kick in the chest when this therapy is delivered. Basic pacing The ICD’s third function is to act as pacemaker. This can be used continuously if there is a need for a chronic pacemaker or on an as-needed basis such as just after delivering a shock.
Learn more about ICDs here:
- Conditions related to implantable cardioverter defibrillators
- Side effects of implantable cardioverter defibrillators
- Research on implantable cardioverter defibrillators
- Treatments related to implantable cardioverter defibrillators