Prolonging pacemaker system longevity and time between pulse generator changes remains an important goal of device therapy for several reasons. There is a small but finite risk of infection and other complications each time a generator change is performed. If patients have one less generator change during their lifetime, the relative risk of complications is reduced. Therefore, interest in maximizing pacemaker longevity continues.
Modern pacemakers use current not only for pacing but also for other functions such as obtaining measurements of diagnostic data, measurements made by rate response sensors, and implementation of algorithms, such as for mode switching. Pacemaker battery life therefore depends on a variety of variables, including baseline battery self-discharge, current drain for device housekeeping functions, current used to pace the heart, and current to sense the underlying heart rhythm.
An average pacemaker battery has about 0. Factors controlling current drain with a pacing stimulus include pacing rate, per cent pacing, programmed voltage, pulse width PW , and lead impedance. Energy use is proportional to PW and to the square of the voltage.
For a given voltage V and PW, current will be less for a high-impedance lead. For an electrical circuit, a voltage drop occurs and energy is dissipated across a load or impedance.
The area of high impedance in a lead should therefore be at the lead tissue interface and not in the lead body itself where energy is wasted. High-impedance leads are designed with a very small diameter electrode to maximize this current density.
The electrode is also made porous with a large surface area to volume ratio to minimize repolarization currents Hemholtz current and to maximize lead tissue interface. If V and PW are constant, then a lead with twice the impedance will only use half as much current. Other factors may be even more important than maximizing lead impedance. These include minimizing the pacing voltage with design features such as autocapture, 2 which perform better using leads with low repolarization.
Repolarization is post-pacing capacitive discharge caused by tissue ion and cation movement in response to a voltage gradient. A high repolarization lead can interfere with detection by autocapture algorithms.
Even pacing with a low voltage does not save as much energy as not pacing at all. Several studies have reported predicted pacemaker battery life extension with high-impedance leads. However, no study has yet followed patients to generator replacement to see if actual time to generator replacement in long-term follow-up is prolonged with high-impedance leads.
Etsadashvili et al. They first reported on these patients in Twenty patients were randomly assigned each to either a standard impedance model T, St Jude Medical or a high-impedance ventricular lead Capture Z, model , Medtronic Inc. All patients were programmed with a three-fold safety stimulation margin. All patients who remained in the protocol were followed regularly with interrogation of pacing parameters, estimated time to replacement, and current drain measured at each follow-up.
Only 16 of the original 40 patients remained in the protocol for final evaluation. Removal from the protocol occurred for reasons such as rise in pacing thresholds, death, and patients moving. At every visit, the patients with high-impedance leads showed significantly higher lead impedance and significantly less ventricular lead current drain.
However, the overall battery current drain was only marginally different in the two groups at all follow-ups except for 39 months.
For the first 6 years, there was a significant increase in pacemaker estimated longevity in the high-impedance group; however, this did not lead to longer device longevity with only a trend for longer generator life in the high-impedance group You'll usually have your pacemaker checked after 4 to 6 weeks at the hospital where it was fitted.
Provided this check is satisfactory, you'll have your pacemaker checked every 3 to 12 months. If after having the pacemaker fitted and leaving hospital you feel you're not getting as much benefit as you imagined, your pacemaker may need some small adjustments.
Signs that your pacemaker isn't working as it should or you have developed an infection or blood clot include:. Contact your GP or cardiologist as soon as possible for advice if you experience any of these problems after having a pacemaker fitted. If this isn't possible, call NHS or your local out-of-hours service. Anything that produces a strong electromagnetic field, like an induction hob, can interfere with a pacemaker. Most common household electrical equipment, such as hairdryers and microwave ovens, won't be a problem, as long as you use them at least 15cm 6 inches away from your pacemaker.
If you have an induction hob, keep a distance of at least 60cm 2ft between the stove top and your pacemaker. If this is a problem, you may want to consider replacing the appliance with something more suitable. If you feel dizzy or feel your heart beating faster while using an electrical appliance, simply move away from it to allow your heart beat to return to normal.
It's safe to use a mobile phone, but make sure you keep it more than 15cm 6 inches from your pacemaker. Use a headset or the ear on the opposite side to the pacemaker. Walking steadily through an anti-theft detector in a shop doorway shouldn't affect your pacemaker, but don't stand too close to this type of security device for long.
Airport security systems don't usually cause problems with pacemakers, but carry your pacemaker identification card with you and tell security staff you have a pacemaker. Security staff in some countries may insist you pass through the scanner. Move quickly through it and don't linger nearby. Handheld metal detectors shouldn't be placed directly over your pacemaker. MRI scanners aren't usually used for people with pacemakers because they produce strong magnetic fields.
Other types of medical tests are safe, but always tell the person treating you that you have a pacemaker.
TENS machines shouldn't be used without first consulting your pacemaker clinic or manufacturer. They produce small electrical impulses that could interfere with your pacemaker. Lithotripsy , a treatment for kidney stones , must be avoided if you have a pacemaker fitted.
If your job brings you into contact with strong electrical fields, such as arc welding, diathermy or working with high-power radio or TV transmitters, or you have direct contact with car ignition systems, check with your cardiologist or pacemaker technician before returning to work. Most pacemaker batteries last for 6 to 10 years.
After this, you may need to have the batteries changed. Ask your doctor how you'll know when the battery needs to be replaced or recharged. Changing the batteries involves replacing the pacemaker box with a new unit. This is a simple procedure that may or may not require an overnight stay in hospital. The original lead or leads can usually be left in place, although occasionally they'll also need to be replaced.
You'll need follow-up appointments for the rest of your life after having a pacemaker fitted. These may be every 3 to 12 months, depending on the type of pacemaker you have and how well it works. At your follow-up appointment, the technician or doctor will analyse the discharge rate of your pacemaker, measure the strength of the electrical impulse, and record the effects of the impulse on your heart. Most modern pacemakers can store information about the state of the battery and the performance of the pulse generator.
Your pacemaker can then be reprogrammed to the best settings for you, if necessary. There's no reason you can't continue to have a good sex life after having a pacemaker implanted and you're feeling better. But you should avoid positions that place pressure on the arms and chest for the first 4 weeks of your recovery. You should tell your doctor, nurse and dentist about your pacemaker, as you may need to avoid some medical tests and treatments, such as MRI scans and the use of TENS machines.
You should also tell your family and close friends that you have a pacemaker fitted. Love and his colleagues also offer consultation on other implant device issues. One patient recently arrived at the clinic feeling miserable because the timed settings between the chambers of the heart were not ideal. We have some tricks to allow us to get it there. Nevertheless, says Love, as devices become more sophisticated, wires can pose a challenge.
Skip Navigation. By Judy F. Published in Cardiovascular Report Spring Johns Hopkins' medical concierge services offer complimentary assistance with appointments and travel planning. Request free assistance:. First Name. Last Name. Yes, I would like to receive additional information from Johns Hopkins Medicine.
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