Some patients with heart failure experience fast, irregular heartbeats. These heartbeats can just be annoying, make you weak and dizzy, or even result in death. Sometimes medicines are used to control these fast heart rates. When medicines do not work, doc-tors can implant an implantable cardioverter defib-rillator (ICD). An ICD is used in patients at risk for:
- Ventricular tachycardia, when the lower chambers of the heart independently beat faster than 100 beats per minute
- Ventricular fibrillation, when the muscle fibers of the lower chambers of the heart contract in a fast, uncoordinated manner
- Sudden cardiac death caused by arrhythmias
The ICD is usually about the size of a pager. It constantly monitors the heart rhythm. When it detects a very fast, abnormal heart rhythm, it can give your heart a lifesaving shock to prevent cardiac arrest.
Like the pacemakers, the ICD is composed of two parts: a battery that generates a pulse and a small computer that monitors the heart rate and determines when a electrical pulse is necessary to change the heart rhythm. The computer and battery are inserted under the skin near the collarbone and are connected to the heart with wires called leads.
Newer ICD devices can also work like a pacemaker if your heart beats too slowly (bradycardias).