Pacemakers & Defibrillators

Information for Patients with Pacemakers or Implantable Defibrillators:

After your device is implanted, your implanting physician or surgeon will arrange to see you within several days to a few weeks, to inspect the incision from your implant procedure. Your device will have been programmed with nominal settings. Nominal settings are parameters that are factory pre-set, and which tend to work best for the majority of individuals under usual circumstances.

Your device maintains a constant surveillance over your heart’s rhythm, and it will automatically intervene (if necessary) according to its pre-programmed parameters. With the usual programmed parameters, implanted devices will provide pacing output only when needed (pacing on demand). As such, they are designed to allow your heart to self-activate and pump normally (without the pacemaker’s electrical assistance) as long as your heart is able to do so. The device’s pre-programmed parameters can be easily changed (re-programmed) at any time that a patient’s situation requires. The majority of pacemakers or implantable defibrillators (ICD) currently in use contain “event counters”, which compile information regarding your heart rates and rhythms. These event counters provide valuable information to your cardiologist, allowing him/her to make the most meaningful adjustments to your device’s settings, so that your device can ultimately be optimized for you. We will regularly assess your pre-programmed settings to determine if they are indeed optimized and individualized. Your pacemaker or ICD will usually be re-programmed during this visit (if necessary), to take advantage of all of the features that may be available. We will attempt to have your device perform at its peak efficiency, while still maximizing your device’s battery longevity.

Your device battery will generally have sufficient voltage to perform according to specifications for several years (under normal circumstances). Battery longevity, however, is variable from device to device, and from individual to individual.

Factors that may affect battery longevity may include: your pacemaker (or ICD) lead(s) capture thresholds, the measured lead impedance, the number of functioning implanted leads in use, the device mode of programming and activated features, and the individual patient’s requirements. (A patient who is completely dependent upon pacemaker output will generally deplete his/her battery faster than a patient who only needs pacing output intermittently.)

Routine surveillance of your device’s performance can be handled by a variety of modalities. You should report to your cardiologist any symptoms that you are experiencing. Occasionally, cardiovascular performance (and symptom improvement) can be managed by adjustment of your medications, adjustment of your implanted device programmed settings, or a combination of both. You may be requested to participate in a remote device-monitoring program (depending upon availability). This program allows us to have an opportunity to “spot-check” your device from a remote location (outside of the cardiologist’s office) with a variable frequency (usually every three to six months – depending upon the need, and depending upon what additional monitoring your insurance carrier will allow) while you are at home, or perhaps while away. Some device manufacturers maintain their own proprietary device monitoring programs, which transmit their data via telephone, cellular, or radio transmission. Some 3rd party vendors may offer monitoring programs that your insurance may allow us to enroll you in, which operate similarly. The company that provides this service will supply you with the appropriate equipment and instructions to complete the home monitoring (telemetry). A computer generated report can then be sent to the Suncoast Heart Institute Pacemaker/ICD Clinic for evaluation. If any irregularities are noted regarding your device’s performance, you will be requested to come to the office for a more detailed formal evaluation, done initially by the manufacturer’s representative, or the physician. Changes in the programming of your device can usually be accomplished to correct any anomalies during the same sitting. This also allows us an excellent opportunity to determine when your pacemaker or ICD battery is exhibiting early warnings of battery depletion.

After your device implant, you will be requested to participate in the Suncoast Heart Institute’s Pacemaker/ICD Clinic. The clinic operates on a designated day where a representative from your device’s manufacturer, or a member of our clinical staff will be present in our office, to perform a formal interrogation (and reprogramming, if indicated). Educational materials (both printed and videos) are available in our facility, to keep you updated regarding your device’s function and maintenance. We are always happy to provide you an opportunity to become more familiar with how your device functions. You should feel free to request videos, printed material, and/or official internet sources to supplement your knowledge of how your pacemaker or implanted defibrillator is working for you.

Your pacemaker or defibrillator device contains circuitry to provide your cardiologist with information to alert him/her when your device battery is showing early signs of depletion. The battery is designed to provide all of the necessary functions throughout its battery life until it has reached complete drainage (termed end-of-life [EOL] or end-of-service [EOS]). There are a number of intervals that will precede this final time period, which will allow your physician to have ample time to schedule you to safely undergo a battery change (generator changeout). These preliminary time zones will generally begin several months in advance of eventual battery depletion. Depending upon your device manufacturer, the first interval is often termed “middle-of-life-1” (MOL1) or “intensive follow-up interval” (IFI). Again, this period begins several months in advance of battery exhaustion, and will indicate to the monitoring physician, that your device will require monitoring more often, to identify the subsequent period, which is termed “middle-of-life-2” (MOL2), “elective replacement interval” (ERI), or “recommended replacement time” (RRT). During this time, you will be requested to make an appointment to have your pacemaker or implantable cardioverter-defibrillator battery (generator) electively replaced. This period usually still allows for several weeks of normal device function before reaching EOL or EOS. It is theorized that during the EOL or EOS period, the patient likely still has several days, or possibly as much as a few weeks of battery life remaining, but some of the device features may no longer function as programmed, and the exact amount of voltage remaining before complete exhaustion is unpredictable. Avoiding a delay in scheduling a generator changeout is even more important for patients who are “pacemaker dependent”. These patients will not demonstrate an underlying rhythm to sustain them, and are completely reliant upon their implanted device for heart rhythm support.

What About……?

Microwave Ovens:

Microwave ovens operate on a limited wavelength, and usually have little-to-no electrical current leakage. They should not interfere in any way with the programming of pacemakers or defibrillators that are currently in use.

Store Security Systems/Strong Electromagnetic Fields:

Store security systems operate using an electromagnetic field. It may be possible for such a system to affect the programming of your pacemaker or ICD, only while you are positioned within the field itself. An electromagnetic field will not shut off the device, but may interfere with the device’s programmed settings (depending upon the sensitivity of the device, and intensity of the interfering electromagnetic radiation). Most of the time, this interference is low-level, temporary, and pre-programmed pacemaker/ICD settings will resume once you move a safe distance away from the security device (usually just a few feet or less). In general, this tends to be of no concern, as most people pass through these systems relatively quickly. It is likely that most individuals would not experience any symptoms at all, even if they remain within the electromagnetic field for somewhat longer than expected. It is suggested that you do not linger close to the detection system equipment. Similar effects can be observed with other equipment that generate strong electromagnetic fields, such as: arc welders, high-voltage power lines, a high-voltage switching station, and with the use of surgical electrocautery.

If you find that you are near such equipment and feel any unusual symptoms (dizziness, palpitations, lightheadedness); move promptly away from the suspected source of electrical interference. If these symptoms should persist in any way (or if you have any concerns that this electrical interference may have had some effect upon your implanted pacemaker or defibrillator device), please call us immediately (or have someone else call for you). We can easily arrange to quickly have your device interrogated (and re-programmed, if necessary). We will want to do whatever can be reasonably accomplished to be certain that your device is programmed properly for you, at all times.

Airport Metal Detectors:

Airport metal detectors are less likely to interfere with programmed pacemaker operation than store security systems. These systems may have the potential to detect the metal in your device. Metal detectors can usually not distinguish between different types of metals. As such, they cannot tell the difference between a cardiac pacemaker or implantable cardioverter-defibrillator, and a metallic weapon.

It may be preferable to alert the TSA security agent that you have a pacemaker or defibrillator, and request a manual security search. It will likely be helpful to show your device identification card to the airport security authority. (It is recommended that you carry your device identification card with you at all times.) Under some circumstances, you may be requested to undergo additional search methods. Ask to be cleared with a hand-held detection device that is held away from your pacemaker. If you have a defibrillator (ICD); you should request a hand search, as an electronic hand-held metal detector has the potential to cause your device to sense fibrillation and deliver defibrillation therapy.

MRI Scanners:

MRI Scanners pose extremely strong electromagnetic fields, and patients that have implanted electronic and/or metallic devices should exercise caution, and be certain that the physician who ordered the MRI imaging procedure is aware of the presence of your implanted device(s).

Besides the ability of the magnetic field to put traction on any ferric (magnetic) metal, there have been additional concerns generated regarding the potential for heating of the pacemaker circuitry or conducting leads, ultimately resulting in, or putting a patient in danger of a device malfunction. The final decision in regards to whether the MRI imaging procedure should be performed, is ultimately up to the supervising radiologist, who must weigh the benefit of the clinical information to be obtained against the risk(s) to the patient and his or her device. More recently, most pacemaker and ICD manufacturers have updated the circuitry in their newer devices that will allow specific patients to have an MRI procedure completed without posing any danger to their implanted electronic device. You should obtain information regarding whether or not your implanted electronic device has been deemed to be “MRI safe”. Even under these circumstances, it is recommended that you inform the staff at the MRI facility that you have an implanted pacemaker or ICD device. You should contact your cardiologist’s office and/or a member of your device manufacturer’s support staff in advance of your procedure to determine whether or not any additional re-programming of your device may be necessary before your MRI procedure is performed, in order to avoid damage to your device, and even possibly after the procedure (to confirm that the electrical field has not affected any of the pre-designated individualized programming). Most radiologists will not permit performance of MRI procedures on patients with older implanted cardiac rhythm devices, that have not been designated as “MRI safe”.

Cellular Telephones:

Cellular telephones generally do not pose much of a problem to an implanted cardiac rhythm device. Cellular telephones transmit a relatively weak electromagnetic signal. Most (if not all) cellular telephones operate at a radio frequency which will not interfere with pacemaker or defibrillator function. There have been rare reports of individuals that felt as if they were experiencing some symptoms, while using a cellular telephone on the same side as their implanted device. If you have specific concerns regarding potential interference between your cellular telephone and your implanted pacemaker or ICD, you should consider minimizing the use of your cellular telephone, carrying the telephone on the side opposite your implanted device, while using the ear on the opposite side of your implanted device to converse (or consider using a headset, plug-in earpiece, or a Bluetooth™ earpiece device).