A cardioverter defibrillator (ICD) is an implantable device that can help treat irregular heart rhythms and greatly improve quality of life.
As opposed to a pacemaker, which continually stimulates the heart to beat at a normal rate, an ICD monitors your heart rhythm and, it if detects an abnormality, delivers a shock to reset the heart.
An ICD is implanted in a similar way to a pacemaker, typically as a day case procedure, either with local anaesthetic and sedation, or under a general anaesthetic, depending on where the ICD is being implanted.
The device is attached to one or two leads that pass through the vein in your chest to your heart. One lead goes into the ventricle or lower chamber of the heart and, if required, one goes into the top chamber of the heart, known as the atrium.
The leads that connect the ICD to the heart are usually thicker, as they contain coils to deliver a shock as well as the components required to check the pace of the heart. The battery or generator that powers the ICD is also usually larger than a pacemaker and is therefore often placed below the chest muscles rather than just below the skin.
The patient will have check-ups every six months to a year, although it's also possible to monitor an ICD wirelessly, transmitting information on how the heart is functioning.