When you have heart failure, the lower chambers of your heart (the ventricles) aren't able to pump as much blood as your body needs. Sometimes, the ventricles also don't pump at the same time.

Cardiac resynchronization therapy (CRT) uses a special type of pacemaker called a biventricular pacemaker (say "by-ven-TRICK-yuh-ler") to treat heart failure. This pacemaker sends electrical pulses to make the ventricles pump at the same time. This can improve your symptoms of heart failure.

A biventricular pacemaker sends signals to both ventricles. The pacemaker connects to three thin wires, called leads. The leads go into different chambers of your heart. If there is a problem with your heartbeat, the pacemaker sends a painless signal through the leads to fix the problem. The pacemaker also can speed up your heart if it is beating too slowly.

In some cases, you may get a pacemaker for heart failure that is combined with a device to shock your heartbeat back to a normal rhythm if it is dangerously fast. The device is called an implantable cardioverter-defibrillator, or ICD. It can prevent sudden death.

Your doctor will put the pacemaker in your chest during minor surgery. You will not have open-chest surgery. You probably will have local anesthesia. This means that you will be awake but feel no pain. You also will likely have medicine to make you feel relaxed and sleepy.

Your doctor makes a small cut (incision) in your upper chest. In some cases, the pacemaker can be placed lower in the chest. This would allow you to wear clothing with a lower neckline and still keep the scar covered. The doctor puts the leads in a vein and threads them to the heart. In some cases, another incision is made to place the lead that goes near the left ventricle. Then your doctor connects the leads to the pacemaker. Your doctor programs the pacemaker and then puts it in your chest and closes the incision.

It can take up to 2 hours to place the pacemaker. It may take 2 to 3 hours if the doctor needs to make an incision to place the lead near the left ventricle.

Most people spend the night in the hospital, just to make sure that the device is working and that there are no problems from the surgery. But sometimes the procedure is done as an outpatient procedure, which means you don't need to stay overnight in the hospital.

You may be able to see a little bump under the skin where the pacemaker is placed.

Whether a pacemaker for heart failure is right for you depends on many medical facts. Your doctor will check whether:¹

• You have class III or class IV heart failure. This means that you have trouble doing everyday activities or you can't do them at all. Activity makes you very tired and short of breath, or you have pain or other problems.
• You are taking medicines for heart failure, but you still have symptoms like being very tired and short of breath.
• You have an ejection fraction of 35% or less. Ejection fraction is a measure of how much blood your left ventricle pumps. A normal ejection fraction is 55% or more.
• Tests show that your heart's ventricles are not beating at the right time. These tests may include an electrocardiogram (EKG, ECG) test, an echocardiogram, or an electrophysiology study.

A pacemaker can help you feel better so you can be more active. It also can help keep you out of the hospital and help you live longer.

• A large study found that 19 out of 100 people who were treated with a pacemaker for heart failure had to go into the hospital during the study because of heart failure. But 27 out of 100 people treated with medicine alone had to go into the hospital for heart failure.²
• In the same study, 13 out of 100 people who got a pacemaker for heart failure died during the study, compared with 16 out of 100 who got only medicine.²
• The combination of a pacemaker and an ICD (implantable cardioverter-defibrillator) can also help people live longer and stay out of the hospital.³

A pacemaker also can help your heart pump better by changing the shape of your heart. In heart failure, the left ventricle often gets too big as it tries to make up for not pumping well. Using a pacemaker may reverse this.

There are several risks to getting a pacemaker. But risks vary for each person. The chance of most problems is low.

• A lead could move out of place. This might happen up to 9 times out of 100. So about 91 out of 100 times, the lead stays in place.⁴
• The pacemaker or leads might not work. This might happen about 7 times out of 100. So 93 times out of 100, the pacemaker and leads do work.⁴
• Problems can happen during the procedure or soon after the procedure. Examples include a lead tearing the heart or a lung collapsing (pneumothorax) from a buildup of air in the space between the lung and the chest wall. Such problems might happen about 10 to 20 times out of 100. So about 80 to 90 times out of 100, no problems happen.⁴ The risk for these problems might be higher for people who are age 80 or older.
• You could get an infection in your chest where the pacemaker is placed. Most of the time, this infection causes the skin to break down around the device. But for a smaller number of people, the infection is in their heart.⁵ An infection might happen about 1 time out of 100. This means that about 99 times out of 100 there is no infection.⁶
• The pacemaker might not be able to be implanted for several reasons, such as when a vein near the left ventricle is too small, too wide, or too hard to reach to allow a lead to be placed. Sometimes the chest or heart may be too big to place a lead. The chance that a doctor can't place the pacemaker is about 10 out of 100. That means the pacemaker can be placed 90 times out of 100.⁴

Your doctor might recommend that you get a pacemaker if all of these are true:

• You have trouble doing everyday activities, or you can't do them at all.
• Your medicines for heart failure aren't helping your symptoms.
• Your heart's ventricles aren't beating at the same time.
• You have an ejection fraction of 35% or less.