What is Cardiac Resynchronization Therapy (CRT)?

A cardiac resynchronization therapy device, also known as a CRT or biventricular pacemaker, is a kind of pacemaker that can help the heart work more effectively. In certain kinds of heart failure, the ventricles, or larger chambers in the heart, stop working together. When they are no longer in synch, the heart can't pump enough blood to meet the body's needs. CRT can help keep the heartbeat regular and the ventricles contracting at the same time.

Just as with a standard pacemaker, a biventricular pacemaker consists of a small battery pack and electrical leads, or small wires that conduct electricity to the heart. CRT pacemakers have two or three leads, placed in the upper and lower chambers of the heart. The device measures the contractions of the heart, and if the heart begins to beat out of time it will send small, rhythmic pulses of electricity to resynchronize (hence the name 'cardiac resynchronization therapy) the contractions. This allows the heart to pump blood to the rest of the body more efficiently. Sometimes a CRT is combined with a different kind of device called an implantable cardioverter-defibrillator or ICD, which uses a higher burst of energy to restart the heart if it stops suddenly.

When a biventricular pacemaker is inserted, the wire leads are usually placed via a small incision near the shoulder, then threaded through a vein to the heart. The battery pack is placed under the skin of the chest near the collarbone. Once everything is in place, the leads are connected to the battery, and the CRT can begin helping the heart beat correctly.

It is normal to experience swelling and discomfort as the incisions from surgery heal. It takes time for the heart to adjust to the pacemaker, so vigorous activity should be kept to a minimum for the first few weeks. Strong magnetic fields may affect how the CRT functions, so you may be advised to avoid them. As your heart begins to pump blood more effectively, you should soon begin to feel stronger and less fatigued.