CRT implantable devices

What happens during implant surgery for a heart failure pacemaker ?

What is CRT ?

Cardiac resynchronisation therapy (much easier to remember as CRT) is a way of treating heart failure with an implantable device similar to a pacemaker. This device uses tiny electrical pulses to both ventricles (lower chambers) of the heart to make them beat together again in a more synchronised pattern.

This improves the heart's ability to pump blood and oxygen to the body. Single therapy systems provide only Cardiac Resynchronisation Therapy. Combined therapy systems are able to provide CRT plus defibrillator therapy (CRT-D) to treat ventricular tachyarrhythmias (VT/VF)

CRT, in combination with a complete programme of therapy, has proven to improve the quality of life for many patients by reducing symptoms of heart failure, increasing exercise capacity, and allowing them to resume many daily activities. It is not a replacement for drug therapy, and it is recommended that anyone choosing to receive CRT also continue taking medication as determined by a physician.

How does CRT work ?

In a conventional pacemaker, only the right ventricle of the heart is stimulated by the device. With CRT both ventricles, or sometimes only the left ventricle, are paced. In patients with the above criteria, this results in a more co-ordinated contraction of the left ventricle, thereby increasing the amount of blood that it can pump around the body. CRT also reduces the pressures inside the heart; in turn, this reduces lung congestion and improves symptoms and signs of heart failure.

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Who is a good candidate for CRT ?

Your doctor may use the following criteria to determine if you are a potential candidate for CRT:

You have ventricular dysynchrony. That means the two lower chambers of your heart are not beating together and are unable to pump blood to the body effectively.
Your medication does not adequately treat your symptoms, and you continue to have a poor quality of life.
Your heart failure has been classified by your doctor as Class III or IV.
Your heart is not able to pump blood effectively (also called low ejection fraction).
You still have symptoms even though you have been taking the maximum amount of medication your doctor has prescribed.
You have a QRS duration of greater than or equal to 130ms. (This is a measurement made on an electrocardiogram).

There are several implantable systems available. The one appropriate for you will be determined by your physician based upon your medical history and whether you are at risk for ventricular arrhythmias.
Single therapy system - provides only Cardiac Resynchronisation Therapy
Combined therapy system - provides CRT plus defibrillation therapy (CRT-D) to treat ventricular tachyarrhythmias (VT/VF)

For some patients, CRT has been shown in clinical trials to:

Improve the ability to exercise and perform other physical activities
Improve quality of life
Improve the New York Heart Association functional class (a classification system developed by the New York Heart Association widely used in the diagnosis of heart failure).

What happens during the device implant?

Implanting a CRT device for heart failure is a standard medical procedure. The device is placed under the skin of the chest and connected to three leads (soft insulated wires) that are inserted through the veins into the heart.

During the procedure you are given medication to make you sleepy and comfortable. After the implant you may see a slight bulge under your skin where the device is located. The leads are very thin and not visible.

You will usually stay in hospital overnight and receive instructions for home care. Movement of the arm near the device may be restricted for a short period after the implant.

Lifestyle changes such as eating less salt, exercising in moderation, and getting enough rest may help relieve some symptoms experienced in all stages of heart failure. Exercise and rest are both important. More about lifestyle changes

Last Updated on: 20.01.2005