Whats a Pacemaker?
A pacemaker is a small device that's placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate.
Pacemakers are used to treat arrhythmias . Arrhythmias are problems with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.
A heartbeat that's too fast is called tachycardia . A heartbeat that's too slow is called bradycardia .
During an arrhythmia, the heart may not be able to pump enough blood to the body. This may cause symptoms such as fatigue (tiredness), shortness of breath, or fainting. Severe arrhythmias can damage the body's vital organs and may even cause loss of consciousness or death.
A pacemaker can relieve some arrhythmia symptoms, such as fatigue and fainting. A pacemaker also can help a person who has abnormal heart rhythms resume a more active lifestyle.
Uses of a Pacemaker;
Faulty electrical signaling in the heart causes arrhythmias. A pacemaker uses low-energy electrical pulses to overcome this faulty electrical signaling. Pacemakers can:
- Speed up a slow heart rhythm.
- Help control an abnormal or fast heart rhythm.
- Make sure the ventricles contract normally if the atria are quivering instead of beating with a normal rhythm (a condition called atrial fibrillation).
- Coordinate the electrical signaling between the upper and lower chambers of the heart.
- Coordinate the electrical signaling between the ventricles. Pacemakers that do this are called cardiac resynchronization therapy (CRT) devices. CRT devices are used to treat heart failure.
- Prevent dangerous arrhythmias caused by a disorder called long QT syndrome.
Pacemakers can be temporary or permanent. Temporary pacemakers are used to treat temporary heartbeat problems, such as a slow heartbeat that's caused by a heart attack, heart surgery, or an overdose of medicine.
Temporary pacemakers also are used during emergencies. They're used until a permanent pacemaker can be implanted or until the temporary condition goes away. If you have a temporary pacemaker, you'll stay in a hospital as long as the device is in place.
Permanent pacemakers are used to control long-term heart rhythm problems.
Doctors also treat arrhythmias with another device called an implantable cardioverter defibrillator (ICD). An ICD is similar to a pacemaker. However, besides using low-energy electrical pulses, an ICD also can use high-energy electrical pulses to treat certain dangerous arrhythmias.
Who Needs a Pacemaker?
Doctors recommend pacemakers for a number of reasons. The most common reasons are bradycardia and heart block.
Bradycardia is a slower than normal heartbeat. Heart block is a problem with the heart's electrical system. The disorder occurs when an electrical signal is slowed or disrupted as it moves through the heart.
Heart block can happen as a result of aging, damage to the heart from a heart attack, or other conditions that interfere with the heart's electrical activity. Certain nerve and muscle disorders also can cause heart block, including muscular dystrophy.
Your doctor also may recommend a pacemaker if:
- Aging or heart disease damages your sinus node's ability to set the correct pace for your heartbeat. Such damage can cause slower than normal heartbeats or long pauses between heartbeats. The damage also can cause your heart to alternate between slow and fast rhythms. This condition is called sick sinus syndrome.
- You've had a medical procedure to treat an arrhythmia called atrial fibrillation. A pacemaker can help regulate your heartbeat after the procedure.
- You need to take certain heart medicines, such as beta blockers. These medicines may slow your heartbeat too much.
- You faint or have other symptoms of a slow heartbeat. For example, this may happen if the main artery in your neck that supplies your brain with blood is sensitive to pressure. Just quickly turning your neck can cause your heart to beat slower than normal. If that happens, not enough blood may flow to your brain, causing you to feel faint or collapse.
- You have heart muscle problems that cause electrical signals to travel too slowly through your heart muscle. (Your pacemaker may provide cardiac resynchronization therapy for this problem.)
- You have long QT syndrome, which puts you at risk for dangerous arrhythmias.
Before recommending a pacemaker, your doctor will consider any arrhythmia symptoms you have, such as dizziness, unexplained fainting, or shortness of breath. He or she also will consider whether you have a history of heart disease, what medicines you're currently taking, and the results of heart tests.
- Holter moniter or Event moniter
- Stress test
- Electrophysiology study
Different kinds of Pacemakers;
Several kinds are used. Most of the devices implanted today are for correcting rhythms that are too slow, and are discussed below. Devices for rapid rates ("AICD's" or defibrillators) will be covered in another area of HeartPoint soon. Pacemaker leads may be placed in the atrium alone, the ventricle alone, or in both the atrium and ventricle depending on the situation.
Single lead pacemakers are used primarily in four situations:
1. When the only problem is with the formation of the initial impulse in the atrium, simply placing a lead in the right atrium will "start things off" when it's needed, and the electrical impulse will then continue normally through the rest of the atrium, the AV node and the ventricles.Dual chamber devices (with one lead in the right atrium and one in the right ventricle) are desirable in many situations. Such devices keep the upper and lower chambers contracting in their proper sequence.
2. When the patient is in chronic atrial fibrillation and the ventricle is going too slow atrial fibrillation. In this case, only a single lead is placed in the ventricle (because the fibrillating atrium cannot be paced).
3. When the problem with a slow rate occurs only occasionally and for relatively brief periods of time, a single lead in the ventricle may be all that is utilized to provide brief help at those times.
4. A special lead which can sense in both chambers, and pace only in the ventricle is also useful in some situations, and is discussed below.
A fairly recent development is a single lead that paces only the ventricle, but senses both chambers. In this device, a sensing ring is on the lead at the level of the atrium, which can sense the atrium's activity. The ventricle is sensed in the usual way, via the contact of the lead with the muscle. This device is particularly useful in situations where the sinus node is beating fast enough, but there is a block in the propagation of the impulse to the rest of the heart muscle.
The earliest pacemakers did not sense if the heart was making any impulses on their own, and were described as "fixed rate" pacemakers. These are simply not made any longer, and current devices are described as "demand" models, pacing the heart only when needed.
Another feature that distinguishes different types of pacemakers is their ability to respond to a person's activity, going faster when the person is active, and slower when inactive.
Most modern pacemakers can be programmed, and can be set in a manner that is best for the particular person in whom it is implanted. There is more on this below.
Surgery to implant a pacemaker is considered a minimally invasive procedure. It is not an open heart surgery, although it can be combined with an open heart surgery if necessary.
The procedure is typically performed in an operating room or in a cardiac catheterization lab. Local anesthesia is given to numb the area of the chest where the procedure is performed, allowing the patient to remain awake while the surgery is performed without pain. In addition to numbing the area, a sedative may be given to help the patient relax or reach a semi sleep state.
Once the anesthesia takes effect, the chest will be prepared with a special solution to remove germs that may be on the skin, and the area will be covered with sterile drapes to keep the incision as clean as possible.
The procedure begins with the insertion of the wires that attach the device to the heart. The wires are threaded through and into the heart where they are placed using a type of x-ray imagining that allows the doctor to see exactly where the wires are at all times. pacemaker device is placed under the skin. The wires, which are connected to the heart, are attached to the pacemaker. The pacemaker is then tested to make sure it is working effectively.
Once the wires are in place, an incision is made in the chest or abdomen, and the actual Once the physician determines that the wires are in the correct place and the pacemaker is functioning properly, the incision is closed with sutures or adhesive strips and medication is given to wake the patient.
What Are the Risks of Pacemaker Surgery?
Your chance of having any problems from pacemaker surgery is very low. If problems do occur, they may include:
- Swelling, bleeding, bruising, or infection in the area where the pacemaker was placed
- Blood vessel or nerve damage
- A collapsed lung
- A bad reaction to the medicine used during the procedure
Lifestyle Changes after implanting a Pacemaker;
Once you have a pacemaker, you have to avoid close or prolonged contact with electrical devices or devices that have strong magnetic fields. Devices that can interfere with a pacemaker include:
- Cell phones and MP3 players (for example, iPods)
- Household appliances, such as microwave ovens
- High-tension wires
- Metal detectors
- Industrial welders
- Electrical generators
Some medical procedures can disrupt your pacemaker. These procedures include:
- Magnetic resonance imaging, or MRI
- Shock-wave lithotripsy to get rid of kidney stones
- Electrocauterization to stop bleeding during surgery
Your doctor will want to check your pacemaker regularly (about every 3 months). Over time, a pacemaker can stop working properly because:
- Its wires get dislodged or broken
- Its battery gets weak or fails
- Your heart disease progresses
- Other devices have disrupted its electrical signaling
Your doctor also may ask you to have an ECG (electrocardiogram) to check for changes in your heart's electrical activity.
Pacemaker batteries last between 5 and 15 years (average 6 to 7 years), depending on how active the pacemaker is. Your doctor will replace the generator along with the battery before the battery starts to run down.
Replacing the generator/battery is less-involved surgery than the original surgery to implant the pacemaker. The wires of your pacemaker also may need to be replaced eventually.
Your doctor can tell you whether your pacemaker or its wires need to be replaced when you see him or her for followup visits.