by Elissa Sonnenberg, MS
Anatomy and Physiology
The heart is a muscular organ with four chambers. Blood collects in the heart's two upper chambers, or atria, before filling the two lower chambers, or ventricles. When the ventricles contract, blood in the right ventricle is pumped to the lungs and blood in the left ventricle is pumped to the rest of the body.
The heart has a natural pacemaker called the sinoatrial node, or SA node. The pacemaker controls the heart rate by precisely determining when the muscles of the atria and ventricles contract.
The electrical signal produced by the SA node reaches the ventricles through a narrow pathway that includes the so-called AV node and bundle branches. Taken together, these pathways are referred to as the conduction system of the heart.
Reasons for Procedure
Sometimes the heart's conduction system does not work correctly. This can occur, for example, if the SA node slows down or a blockage develops in the bundle branches. These problems can be due to heart disease, medications, or cardiac surgery.
Failure of the conduction system may slow the heart rate or cause the chambers of the heart to contract out of their proper sequence. If this occurs, insufficient blood may reach the body, leading to symptoms like tiredness, shortness of breath, or fainting.
A pacemaker is a small, battery-powered device made up of two parts, a pulse generator and the leads. The pulse generator gives off impulses that cause the atria and/or ventricles to contract. It is positioned under the skin, below the collarbone on either side of the chest.
The leads carry signals between the pulse generator and the heart in both directions. Pacemakers often have two leads, one resting in the right atrium and the other in the right ventricle. They are inserted into the subclavian vein and threaded to the right atrium and ventricle.
If one of the leads detects an abnormal signal in the conduction system, it will instruct the pulse generator to send an electrical impulse to the heart to compensate.
The surgeon will make a small incision beneath your collarbone. The pacemaker's leads will be inserted into the subclavian vein and then threaded toward the right side of your heart. Your surgeon will view x-ray images on a video screen to position the leads correctly.
In the days leading up to your procedure: Arrange for a ride to and from the hospital and for help at home as you recover. The night before, eat a light meal and do not eat or drink anything after midnight. Go to the bathroom before your procedure. If you regularly take medications, herbs, or dietary supplements, your doctor may recommend temporarily discontinuing them. Do not start taking any new medications, herbs, or dietary supplements before consulting your doctor. You may be given antibiotics to take before coming to the hospital.
Before the procedure, your blood and urine will be tested. You will also have x-rays taken of your chest and an electrocardiogram, or EKG, will record the electrical activity in your heart.
Before the procedure, your chest and shoulder will be washed with antiseptic. Sterile sheets will be put over you to keep the area clean. An injection of a local anesthetic into your skin will numb the area where the pacemaker will be inserted.
The surgeon will make a small incision beneath your collarbone. The pacemaker's leads will be inserted into the subclavian vein and then threaded toward your heart until they reach the right atrium. Your surgeon will view x-ray images on a video screen to position the leads correctly.
Once the leads have been tested, they will be connected to the pulse generator. The pulse generator will then be placed in a small pouch that your surgeon will create under the skin beneath your collarbone. Your surgeon will then sew the incision back together.
While you're in the hospital, your doctor will monitor your heart rate and blood pressure to be certain the pacemaker is working properly. Before you leave, he or she will make final adjustments to the pacemaker settings.
Risks and Benefits
Possible complications of pacemaker insertion are rare, but include: excessive bleeding, surgical-wound infection, pacemaker malfunction. Very rare complications include: rupture of the heart muscle, heart attack.
Benefits of pacemaker insertion include: An improvement in symptoms resulting from a problem with the heart's conduction system such as shortness of breath, tiredness, and fainting, a more regular heartbeat, no need for a large incision or a lengthy recovery period; most patients find that they can resume their normal activities within a couple of weeks.
In a pacemaker insertion, or any procedure, you and your doctor must carefully weigh the risks and benefits to determine whether it's the most appropriate treatment choice for you.
After the Procedure
Most patients are able to leave the hospital the day after the procedure. At home, over-the-counter pain medications, such as acetaminophen or ibuprofen, should be sufficient to relieve any pain. Do not plan on driving again for at least 2 weeks. You will need to periodically follow up with your doctor to test and adjust your new pacemaker.
Once you are home, be sure to contact your doctor if you experience: signs of infection, such as fever and chills, redness, swelling, increasing pain, bleeding, or discharge at the site of your incision, cough, shortness of breath, or chest pain, severe nausea or vomiting, recurrence of any symptoms that originally lead to your pacemaker insertion, which may indicate a malfunction, and/or lightheadedness or fainting.
- Heart and Stroke Facts. American Heart Association. Available at: http://www.americanheart.org/downloadable/heart/56719919740HSFacts2003text.pdf. Accessed June 26, 2004.
- Living with your Pacemaker, American Heart Association. Available at: http://www.americanheart.org/presenter.jhtml?identifier=33. Accessed June 26, 2004.
- Pacemaker implant. Queensland Government website. Available at: http://188.8.131.52/informedconsent/ConsentForms/tpchcardiac/pacemaker_implant2.pdf. Accessed June 26, 2004.
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