An implantable cardioverter-defibrillator (ICD) is a small, battery-powered device surgically placed in a patient's chest to monitor and detect irregular heartbeats (arrhythmias). If an ICD detects a dangerous heart rhythm, it delivers an electric shock via one or more wires (leads) connected to the heart to restore its regular rhythm.
When an ICD detects a dangerous heart rhythm, it sends an electrical pulse to the heart. An ICD can be programmed by a physician for different things.
If an ICD needs to restore a normal heartbeat, whether with low-energy pacing or a high-energy shock, the heart rhythm is recorded. This is transmitted to a device specialist for interpretation and communicated to the patient's physician.
Yes. Standard ICDs are surgically placed under the skin, usually just below the left collarbone, and one or more flexible leads run from the ICD through the veins to the heart (pictured above).
A subcutaneous ICD (S-ICD) is a newer type of ICD. An S-ICD is implanted under the skin at the side of the chest below the armpit (pictured right). Instead of having leads inserted into the heart, it is attached to one long electrode that runs along the patient's breastbone. An S-ICD is less invasive than a traditional ICD.
Yes. A pacemaker is a small device implanted in a patient's chest that is able to regulate a heartbeat by pacing. Unlike an ICD, a pacemaker is unable to shock a heart.
Yes. Risks during implantation are uncommon, but can include:
There is also the possibility that the device stops working properly or can malfunction. If the ICD missenses a heart rhythm, it can deliver a shock to the heart when a shock isn't necessary. This is called an inappropriate shock. An inappropriate shock can also happen if a lead breaks in the heart. There are ways to turn off an ICD if there is a malfunction until the ICD can be repaired or replaced.
Yes. An ICD uses a lithium battery. Depending on how often the ICD is activated, the battery can last up to seven years. Patients with ICDs generally have six-month checkups where their battery level is checked. Once the battery runs low, the old generator is replaced with a new one during a minor procedure.
This is a hard question to answer and varies greatly depending on who you speak to. Generally, patients who have an ICD have survived a cardiac arrest or have fainted due to a confirmed, dangerous arrhythmia. For more information about who should and shouldn't get an ICD, you can view these videos by Dr. Ackerman.
"Most patients with a cardiac channelopathy do not need an ICD."
Meet other people talking about genetic heart disorders and ICDs on Mayo Clinic Connect. Join the Heart Rhythm Conditions group to join the conversation, share experiences, ask questions, and discover your support network.
For up-to-date information, please follow Dr. Ackerman and the Windland Smith Rice Genetic Heart Rhythm Clinic on Twitter by clicking the links below.