Implantable Cardioverter Defibrillator
Implantable cardioverter defibrillators (ICDs) are devices that are implanted in the chest and designed to monitor and treat unsafe arrhythmias, such as ventricular tachycardia (VT) and ventricular fibrillation (VF).
ICDs are implanted in patients with a high risk for these abnormal rhythms. In general, patients with ICDs have a low heart function with areas of scarring that puts them at risk for VT/VF. The low heart function can be from coronary artery disease or a previous heart attack. Other diseases or conditions that make the heart weak have a similar risk for VT/VF and can be treated with an ICD.
An ICD monitors heart rhythms. If it senses dangerous rhythms, it delivers a shock called defibrillation. This can help control life-threatening arrhythmias. Most new ICDs can also act as a pacemaker.
Implanting an ICD is very similar to implanting a PPM, including the preparation, sedation, anesthesia and post-operative care. While many patients may never experience an abnormal rhythm and never require device therapy, others may have multiple episodes. Unfortunately, there is no reliable way to predict who will and will not need the device to terminate the abnormal rhythm.
Biventricular ICDs are designed to protect the patient from abnormal ventricular rhythms and to attempt to treat the patient’s heart failure. Biventricular ICDs are designed to pace the bottom chambers of the heart all the time. This requires an extra lead when compared to a normal ICD. The lead is inserted through a vein that runs on the outside of the heart. The insertion of a biventricular ICD is similar to the insertion of normal ICDs. Placing the extra lead can add time to the procedure.
Subcutaneous ICDs (SICDs) perform most of the functions of a normal ICD but the components of the device are implanted under the skin and on the chest wall. There are no parts that are in the heart. The device is designed to recognize and terminate abnormal ventricular arrhythmias by shocking the heart back to normal. These types of device cannot terminate the arrhythmia like a normal ICD and have limited capabilities after the providing shock.