All About Pacemakers

A pacemaker is a small device that is implanted under the skin in the chest to help the heart beat the way that it should. Pacemakers send electrical signals to the heart to make sure that heart rate is never too slow.

You might only need a pacemaker for a while, like when you're healing from surgery. If you have a heart condition, you might need a pacemaker for life.

This article discusses how pacemakers work, when they are used, how they are placed, and how to tell if there's a problem with your pacemaker.

How Pacemakers Work

Pacemakers do not take over the work of the heart. Rather, a pacemaker helps regulate the timing and sequence of your heartbeat, as needed.

After it is put in, the pacemaker monitors your heart's electrical activity. If your heart rate is too slow, the device will kick in and send a tiny electrical signal to the heart muscle that tells it to squeeze (contract).

This "decision making" is done by the pacemaker on a beat-to-beat basis.

In most people with pacemakers, the heart's own electrical system is generating most of the heartbeats. The pacemaker functions more like a safety in the event help regulating the heart rate is needed.

Others may need may need pacing nearly all the time. If their pacemaker stopped working, they would have serious symptoms.

Parts of a Pacemaker

Pacemakers are able to appropriately regulate heart beats because of two main parts: the generator and the leads.

The generator is like a tiny computer that has a battery and other electronic pieces. It is inside a hermetically sealed titanium container.

Most modern pacemaker generators are about the size of a 50-cent piece and about three times as thick.

A lead is a flexible, insulated wire that carries electrical signals between the pacemaker generator and the heart. One end of the lead is attached to the generator, and the other end is put through a vein into the heart.

Today, most pacemakers use two leads: one placed in the right atrium and the other in the right ventricle.

Types of Pacemakers

There are a few different types of pacemakers:

• Transvenous: This is the traditional type of pacemaker. It can be a single-lead or double-lead. It has a pulse generator, wires (leads), and electrodes. The wires are connected to the veins and send pulses to the heart.
• Biventricular: This type of pacemaker sends pulses to both of the heart's ventricles (bottom chambers) and one of the heart's atria (upper chamber).
• Epicardial: With this type of pacemaker, the electrodes are attached to the surface of the heart instead of within its chambers.
• Wireless (leadless): With this pacemaker, the generator and electrodes are contained in one device that's placed inside a heart chamber. It's only about the size of a large pill capsule.
  

Pacing and Programming

Pacing can be done from the right atrium, the right ventricle, or both.

When the pacemaker decides that pacing is needed, it prompts the heart chambers to pace. This is called “intelligent pacing” and it helps make sure that the heart rate is meeting the body’s needs and that the heart chambers are working together.

Pacemakers are also "programmable," and the functions they do can be changed at any time.

Programming a pacemaker is done by wirelessly with a special device called a programmer, which , sends new instructions to the generator.

Your healthcare provider can easily reprogram your pacemaker to have it pace at a different rate.

Rate-Responsive Pacemakers

Today, almost all pacemakers can vary the rate at which they pace, depending on what your needs are. These pacemakers are called rate-responsive pacemakers.

These let the heart rate go up as it should when someone is, say, exercising. And when they are at rest, the pacemaker is usually not pacing.

Rate-responsive pacing allows a person to be much more active with much less fatigue.

Rate-responsive pacemakers use several technologies to determine the optimal heart rate, but two are especially useful:

• An activity sensor detects body movement. The more active you are, the faster the pacemaker will pace your heart within the range of heart rates that your provider sets.
• A breathing sensor measures your breathing (respiratory rate). Since you're likely being more active the faster you’re breathing, the pacemaker will pace faster within the pre-set range.

Either technology allows rate-responsive pacemakers to mimic the normal, moment-to-moment changes in heart rate that would happen with a normal heart rhythm.

Who Needs a Pacemaker?

There are a few reasons why the heart might not beat correctly. Pacemakers are commonly used to treat cardiac arrhythmias that cause a person's heartbeat to be too slow (bradycardia). For example, sick sinus syndrome and heart block can cause bradycardia.

The symptoms of bradycardia include weakness, fatigue, lightheadedness, dizziness, or fainting. A pacemaker can make these symptoms go away.

In some people with heart failure, a special type of pacemaker can make sure the heart chambers (the atria and ventricles) beat when they are supposed to.

These pacemakers are called cardiac resynchronization therapy (CRT) devices. They can improve function and symptoms in many people with heart failure.

The device can also help people who have other heart problems, including:

• Tachycardia (a heartbeat that is too fast)
• Heart defects or diseases
• Heart attack
• Heart transplant
• Enlarged heart
  

How Pacemakers Are Placed

You may get a pacemaker put in if you're having heart surgery. It can also be done as an outpatient procedure with local anesthesia so you don't feel anything and medicine to help you feel relaxed.

Here are the steps of placing a pacemaker:

1. First, the generator is put under the skin beneath the collarbone (clavicle).
2. Next, the leads are threaded through a nearby vein and put into position inside the heart.
3. Then, the ends are plugged into the generator.

A pacemaker implantation procedure usually takes about an hour but can take longer.

What Is Life Like With a Pacemaker?

Most people with a pacemaker find that it greatly improves their quality of life. They may even live longer with a pacemaker than they would have if they didn't have one.

Living with a pacemaker does not exactly have "downsides," but because it is a medical device that uses special technology, there are some things you need to be aware of if you have one.

You may need to take steps in certain situations to avoid problems with your pacemaker. You also need to know how to recognize that something is wrong with the device.

Avoiding Electrical Interference With a Pacemaker

There are some things you'll need to avoid doing if you have a pacemaker because electrical interference can make the device not work.

For example, you don't want to spend a lot of time around devices that can give off electromagnetic waves, including:

• Jumper cables, welding equipment, gas-powered equipment, ignition systems, portable car battery starters
• Workout equipment like electronic body fat scales and "ab stimulating" devices
• Magnets
• Electric fences or electric pet products
• CB/ham radios

Also, you should keep these devices, and any other electronic devices, more than six inches away from your pacemaker generator: 

• Medical alert and fall detection devices
• Clip-on and earbud headphones
• Cell phones and MP3 players
• Anti-theft devices on products in stores

You should also move quickly through any metal detector devices you encounter.

Your provider may want you to avoid having certain medical procedures that can interfere with your pacemaker, including:

• Shock-wave lithotripsy
• MRIs
• CT scans
• CAT scans
• Electrocautery
• Diathermy (high-frequency, short-wave, or microwave)
• Microwave ablation
• Some kinds of radiation therapy
• TENS therapy
• Electrolysis

Signs of a Problem With Your Pacemaker

You need to know how to tell if your pacemaker is malfunctioning or failing. Signs of a problem with your pacemaker include:

• Fainting or losing consciousness
• Having a slow heartbeat
• Having heart palpitations
• Having chest pain or discomfort
• Having trouble breathing or feeling short of breath
• Feeling dizzy or lightheaded
• Abdominal muscle twitching
• Hiccups

If you are having these symptoms and think something might be wrong with your pacemaker, call your provider right away.

Replacing Your Pacemaker

While most people living with a pacemaker don't think about it often, it does require a little bit of maintenance. You will need to have your pacemaker checked from time to time.

Once the battery starts to get low—usually after 7 to 10 years—the pacemaker generator will need to be replaced. This can usually be done as an outpatient procedure.

Summary

A pacemaker can be a lifesaving device. Most people who have a pacemaker to help their heart work better feel that it improves their quality of life and they may even live longer than they would have if they didn't have one.

Living with a pacemaker does mean you'll have to stay aware of how it's working. If you're noticing signs of a problem with your pacemaker or you've had it for 7 to 10 years, it might be time to have it replaced.