These devices are smaller and “smarter” than ever before, helping you live a more active life

Pacemakers steady the heart’s beat: these devices are smaller and “smarter” than ever before, helping you live a more active life

There may have been times in your life when your heart “skipped a beat”-possibly at the sight of your true love or the car you had always dreamed of owning. For millions of Americans, though, irregular heartbeat is a chronic and potentially dangerous health condition.

Fortunately, pacemakers can restore healthier heart rhythms in people with an irregular heartbeat. About three million people worldwide have a pacemaker, and each year doctors implant another 600,000 of these devices, according to the American Heart Association.

People of any age may need pacemakers if problems in their heart’s electrical system cause abnormal heart rhythms (arrhythmias), but the majority of pacemaker recipients are people over 60 who have bradycardia (an unusually slow heart rate). Untreated, this arrhythmia can cause fatigue, fainting spells and, in some cases, even sudden death.

Thanks to modern electronic circuits, computerized memory, sensors, and long lasting batteries, today’s pacemakers can regulate heart rhythms in a package smaller than a pager. “All of these devices are far smaller than earlier models and are remarkably ‘smarter’ and more efficient,” says electrophysiologist Davendra Mehta, MD, PhD, director of the Cardiac Arrhythmia Program at Mount Sinai.

How they work

Normally, your heartbeat is controlled by the sinus node, the heart’s natural pacemaker. The sinus node generates an electrical signal that travels from the heart’s upper chambers (the atria) to the lower chambers (the ventricles) and causes the heart to beat. Problems with the sinus node or the movement of this signal can interfere with the heart’s normal beat.

Sick sinus syndrome (SSS) is a group of conditions that occur when the sinus node doesn’t work as well as it should. As a result, the heart beats too slowly or too quickly. SSS, which is most common in people 65 and over, can slow the heart rate to the point that it causes fatigue, shortness of breath, and fainting.

Heart block, the other main cause of bradycardia, can develop spontaneously with age or after a heart attack or other illness. Heart block prevents electrical signals from the atria from moving normally to the ventricles.

“A pacemaker corrects both these causes of symptomatic bradycardia by replacing or supplementing a defective natural pacemaker or blocked pathway in the heart. It sends electrical impulses to the heart via an electrode placed next to the heart wall and causes the heart muscle to begin the contractions that cause a heartbeat,” Dr. Mehta says.

Pacemaker choices

The specific kind of pacemaker you need depends on your diagnosis and where the leads must be placed to correct your arrhythmia. Most are demand pacemakers, which means they have an onboard sensing device that turns the signal off when the heartbeat rises above a certain level and turns the signal back on when the heart beats too slowly. Pacemakers can also be rate adaptive, adjusting the heart rate depending on your activity level. For example, if you are jogging or dancing, the pacemaker will help your heart beat faster.

Pacemakers used to treat symptomatic bradycardia can be either single or dual-chambered. Single-chamber pacemakers have one lead wire that goes into either the upper or lower chambers of the heart. The dual-chambered version has two leads, one for each of the heart’s chambers.

A biventricular pacemaker uses three lead wires to help people with severe heart failure, a condition in which the heart’s pumping power is weakened. “With heart failure, all parts of the lower chambers of the heart don’t contract at the same time, so the heart has less time to fill and pump enough blood out to the body. A biventricular pacemaker paces both chambers of the heart and keeps all walls of the ventricles pumping together,” Dr. Mehta explains. “Research has shown that this improves the symptoms of heart failure (fatigue, shortness of breath, and exercise intolerance) and can dramatically improve the patient’s quality of life.”

Implantable cardioverter-defibrillators (ICDs) are devices similar to pacemakers. ICDs contain capacitors that shock the heart back into a regular rhythm if a life-threatening arrhythmia occurs.

Implanting a pacemaker

The procedure to insert a regular pacemaker takes about 45 minutes (an ICD can take about 90 minutes to insert). The surgeon guides the lead wires through a vein to the upper or lower heart chambers (depending on the diagnosis), and attaches them to the heart muscle. The other ends of the leads are attached to the pulse generator, which is implanted under the skin in the upper left or right side of the chest.

Although not major surgery, pacemaker insertion does have risks, including heart injury, stroke, heart attack, and lung injury. “However, the odds of serious complications are less than one in 500,” Dr. Mehta notes. “You may have a little arm pain the next day or two after receiving your pacemaker, but people are usually back at work in three to four days. Most people feel better almost right away-especially if they had previously been having blackouts or extreme fatigue due to bradycardia.”

Once you have your pacemaker implanted, your cardiologist should check it every three to six months. Your doctor will use a computer to analyze how the pacemaker is working and how much power the battery has left (batteries usually last five to 10 years before needing replacement). To change the battery, the pulse generator placed under the skin is removed–a procedure that takes about 30 minutes.

According to research published in Circulation: Journal of the American Heart Association, the cumulative cost for a dual-chamber pacemaker (including the cost of implantation) during the first four years is about $27,441, as compared to $26,760 for a single-chamber device. Insurance and Medicare usually pay for pacemakers if they are deemed medically necessary.

An imperfect science

Despite their long record of helping hundreds of thousands of people, these expensive–and complicated–devices aren’t without occasional glitches, including recalls that have grabbed national headlines (like the recent recall of certain Guidant pacemakers due to a defect).

“Anything that is so complex and is made by human beings will sometimes have some malfunctions, but the incidence is fairly low,” Dr. Mehta says. “We notify patients when there is a recall and take care of whatever problem there might be–it usually takes about half an hour if we have to change the hardware and battery.”

New versions of pacemakers on the horizon promise to make checking and maintaining the devices even easier. “Today’s pacemakers store events, such as an episode of a rapid heart rhythm, for your doctor. A small ‘wand,’ technically called a programming head, works much like a computer modem via a special computerized device plugged into the phone, sending information about the pacemaker to a central computer center. So you can have your pacemaker checked every one to two months this way, in between visits to your physician,” Dr. Mehta explains.

However, technology will soon allow all pacemakers to be monitored over the Internet through a small modem USB port that will transmit pacemaker information from 50 yards away and allow for weekly checking. “Whether you are in bed or sitting in your den, as long as you are within 50 yards of your computer at a fixed time, the computer will check your pacemaker automatically,” Dr. Mehta says.

WHAT YOU CAN DO

* If your doctor gives you the OK, make daily exercise a goal, but avoid activities such as roughhousing with your grandkids, because any direct impact could damage your pacemaker.

* Help manage your pacemaker by taking your pulse for a full minute each day. (Simply count your pulse for sixty seconds.) If it is five beats or more below the programmed rate, contact your doctor to see if the pacemaker needs adjusting.

* Always carry an identification card that shows you have a pacemaker. In case of an accident, it will alert the people aiding you that you have a pacemaker. Presenting your ID card and requesting a hand search can save you inconvenience when traveling, too (pacemakers can set off metal detectors).

* Keep all medical appointments for regular check-ups and make sure your doctor’s office has your most current contact information so you can be easily reached in case your pacemaker is recalled.

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