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Your artificial pacemaker is a modern marvel: its medical science‟s solution to the electrical problems of a slow or irregular heartbeat. Pacemakers are battery-powered implantable devices that function to electrically stimulate the heart to contract and thus to pump blood throughout the body. Pacemakers are usually implanted in patients in whom the heart‟s own “spark plug” or electrical system is no longer functioning normally.

Why would I need a pacemaker?
The heart‟s normal “spark plug” is an area of specialized heart tissue called the SA node, which is located in the right atrium, or right upper chamber. These special cells produce electrical impulses, which cause your heart to contract and pump blood. The impulses travel from the special pacemaker cells (SA node) down certain electrical paths in the muscle walls, causing a contraction. As long as the electrical impulses flow down your heart‟s walls at regular intervals, your heart pumps at a rhythmic pace. Sometimes, though, something happens to interfere with how the electrical impulses of your heart‟s natural pacemaker are made or flow down your heart. When this occurs, the natural pacemaker can‟t do its job as well as it needs to and blood isn‟t pumped around your body well. A pacemaker will make your heart beat more regularly.

How does a pacemaker work?
An artificial pacemaker system has two parts: a generator and wires (leads) The pacemaker generator is a small battery-powered unit. It produces the electrical impulse that starts your heartbeat. The generator is connected to your heart through tiny wires that are implanted at the same time as the generator. The impulses flow through these leads to your heart and are timed to flow at regular intervals just as impulses from your heart‟s natural pacemaker would.


Are there different kinds of pacemakers?
Most pacemakers work only when they‟re needed and are called demand pacemakers. Demand pacemakers have a sensing device that shuts them off if the heartbeat is above a certain rate. When the heart is beating slower than the pacemaker rate, the sensing device turns the pacemaker on again. In this way, a demand pacemaker works something like a thermostat. The difference is that instead of working according to temperature, it works according to your heart rate.

Does my pacemaker require check-ups?
As with any electronic device, your artificial pacemaker will require some care. The batteries, for example, will wear down over time and the pacemaker will need to be replaced. This is a minor surgical procedure. You will most likely have telephone checks regularly to check the battery life. Don‟t worry, your pacemaker will slow down as the batteries wear down, but it won‟t stop right away. A sudden, major slowing down of your heart rate, which you may detect, probably indicates a more serious problem. If that occurs, call your doctor. If you have an artificial pacemaker, be aware of your surroundings and the devices that may interfere with pulse generators. This list will help you understand what type of devices may affect the performance of your pacemaker. Make sure that you always have identification with you that advises others that you have a pacemaker. And always tell your doctor or dentist before they administer any testing that uses medical or electronic devices.


Devices with little or no risk: Home appliances — CB radios, electric drills, electric blankets, electric shavers, ham
radios, heating pads, metal detectors, microwave ovens, TV transmitters and remote control TV changers, in general, have not been shown to damage pacemaker pulse generators, change pacing rates or totally inhibit pacemaker output.

Dental equipment — This doesn't appear to negatively affect pacemakers. Some
patients may feel an increase in pacing rates during dental drilling.

Diagnostic radiation (such as screening X-ray) — This seems to have no effect on
pacemaker pulse generators.

Devices with risk: Anti-theft systems, also called electronic article surveillance (EAS) and metal detectors — Interactions with EAS systems and metal detectors are unlikely to
cause clinically significant symptoms in most patients. However, the American Heart Association recommends that you:  Be aware that EAS systems may be hidden/camouflaged in entrances and exits in many commercial establishments; pass through doorways smoothly and move away from anything that causes you to feel your heart „race” or “flutter”. Don't stay near the EAS system or metal detector longer than is necessary and don't lean against the system. If scanning with a hand-held metal detector is necessary, warn the security personnel that you have an electronic medical device and ask them not to hold the metal detector near the device any longer than is absolutely necessary. You could also ask for an alternative form of personal search.

 

Cellular telephones — Cell-phones available in the United States (less than 3 watts)
don't appear to damage pulse generators or affect how the pacemaker works. But technology is rapidly changing as the Federal Communications Commission (FCC) is making new frequencies available. Newer cell-phones using these new frequencies might make pacemakers less reliable. A group of cell-phone companies is studying that possibility. To be on the safe side, do not carry your cell-phone in a shirt pocket on the same side as your generator.


Extracorporeal shock-wave lithotripsy (ESWL) — This is a noninvasive
treatment that uses hydraulic shocks to dissolve kidney stones. This procedure may be done safely in most pacemaker patients, with some reprogramming of the pacing. You'll need careful follow-up after the procedure and for several months to be sure your pacemaker is working properly. ESWL should be avoided in patients with certain kinds of pacemakers implanted in the abdomen. Discuss your specific case with your doctor before and after the treatment.

Magnetic resonance imaging (MRI) — This is a noninvasive diagnostic tool that
uses a powerful magnet to produce images of internal organs and functions. Metal objects are attracted to the magnet and are normally not allowed near MRI machines. The magnet can interrupt the pacing and inhibit the output of pacemakers. If MRI must be done, the pacemaker output in some models can be reprogrammed. Discuss with your doctor the possible risks and benefits before you undergo MRI scanning.

Medical equipment — Carry a wallet ID card with you. Equipment used by doctors
and dentists can affect your pacemaker, so tell them you have one.

Power-generating equipment, arc welding equipment and powerful magnets (as in medical devices, heavy equipment or motors) — These can
inhibit pulse generators. Patients who work closely with or near such equipment should be aware of the risk that their pacemakers may not work properly in those conditions. Also be aware of leaning over the car battery while the car is running.

Radiofrequency ablation — This uses radio waves to manage a wide variety of
arrhythmias. Recent studies showed most permanent pacemakers aren't adversely affected by radio frequencies during catheter ablation. A variety of changes in your pacemaker can occur during and after the treatment. Your doctor should carefully evaluate your pacing system after the procedure.


Short-wave or microwave diathermy — This uses high-frequency, high-intensity
signals. These may bypass your pacemaker's noise protection and interfere with or permanently damage the pulse generator.

Therapeutic radiation (such as for treating cancerous tumors) — This may damage
the pacemaker's circuits. The degree of damage is unpredictable and may vary with different systems. But the risk is significant and builds up as the radiation dose increases. The American Heart Association recommends that the pacemaker be shielded as much as possible and moved if it lies directly in the radiation field. If you depend on your pacemaker for normal heart pacing, the electrocardiogram (ECG) should be monitored during the treatment, and your pulse generator should be tested often after and between radiation sessions.

Transcutaneous electrical nerve stimulation (TENS) — This is used to relieve
acute or chronic pain. Several electrodes are placed on the skin and connected to a pulse generator. Most studies have shown that TENS rarely inhibits bipolar pacing. It may sometimes briefly inhibit unipolar pacing. This can be treated by reprogramming the pulse generator.

Remember: Always carry your pacemaker ID card and inform medical/dental
providers of your implanted device.

EECP Heart Center


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