Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) is a treatment for some cases of heart failure. In heart failure, the heart does not pump blood with appropriate efficiency. In some patients, this inefficiency is due in part to a failure of the walls of one heart chamber (left ventricle) to contract all at the same time to pump blood, as it would normally. In CRT a device called a biventricular (BiV) pacemaker or pacer is surgically implanted in the chest near the heart. It produces electrical signals to make the walls of the left ventricle pump properly. The BiV pacer can improve symptoms of heart failure, keep an affected individual from needing to go to the hospital for the condition, and help people with heart failure live longer. This type of pacemaker includes a device with a battery and small computer that the physician programs to send electrical signals to the heart when appropriate. It is similar in appearance to other pacemakers that help treat cardiac arrhythmias, but has three wires ("leads") instead of two. Depending on the diagnosis, the doctor might use a "combined" device, which has a BiV pacemaker plus an implantable cardioverter-defibrillator (ICD) that can sense and treat abnormal heartbeats that could cause sudden death.