Frequently Asked Questions

Standard electric toothbrushes and ultrasonic toothbrushes should not interfere with an implanted pacemaker. When we tested two ultrasonic toothbrush models with St. Jude Medical pacemakers, there was no adverse interaction. There haven’t been any patient or clinical reports of an interaction between ultrasonic toothbrushes and pacemakers.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Cardiac pacemakers are electronic devices with sensing circuits which detect small electrical signals from inside the heart. Pacemakers may detect extraneous electrical signals from other sources. The pacemaker can incorrectly interpret these signals as heart activity, which may inhibit the pacemaker. The result could be no output pulse or asynchronous pacing. Asynchronous pacing means that there is no coordination between the heart and the pacemaker.

If you have a St. Jude Medical pacemaker and use or are in close proximity to an electric welder, you shouldn’t have any problems. However, this doesn’t mean that there is a total absence of the effects of welding interference on pacemakers. Any problems caused by radiated interference will end when the arcing ends.

Review Precautions for Electric Arc Welding [PDF 81KB]

Need additional information? Contact Cardiac Rhythm Management Technical Support.

St. Jude Medical pacemakers have a magnetic coil inside. If you have an implanted pacemaker, do not use a magnetic mattress pad or magnetic necklace. If your pacemaker and a magnetic item are near each other, the magnetic field may activate the reed switch\telemetry coil inside the pacemaker.

Items such as magnet insoles, belts, knee braces, and join wraps (below the waist) do not affect the pacemaker.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

TENS devices can interact with pacemakers. Most likely, a temporary inhibition will occur. To minimize the potential for interaction with a TENS device, program the pacer to the bipolar mode and decrease the sensitivity level.

For Physicians & Health Care Professionals
Warnings

1. Burst mode is contraindicated and can result in the pacemaker’s total inhibition.
2. Temporary single beat inhibition due to over sensing of the electrical stimuli may occur.

Take the following steps to minimize complications:

1. Monitor the patient’s heart rate during the procedure.
2. Place the electrode left to right (lateral not anterior-posterior).
3. Place electrode pads close to each other.
4. Always maintain a high frequency (>30 Hz).
5. Program pacemakers that use impedance based sensors (such as minute ventilation or stroke volume for rate responsive pacing) to a non-rate responsive mode to prevent increased pacing rates during TENS therapy.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

The use of therapeutic ultrasound should be okay and is not contraindicated for pacemaker recipients. There is a remote possibility of single beat inhibition of the pacemaker, which may result due to the pacemaker’s inappropriate sensing of the ultrasonic waves. Component damage could occur if the ultrasonic waves are aimed directly at the implanted pacemaker.

This possibility decreases with the therapy distance from the pacemaker. Do not use therapeutic ultrasound within six inches of the pacemaker. Inhibition is less likely if the pacemaker is programmed to the bipolar mode.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Today's implantable device technology uses complementary metal-oxide semiconductor (CMOS) integrated circuits. Low current consumption CMOS circuits are a breakthrough in the implantable device industry due to their inherent low current consumption, allowing for greater device longevity while keeping the size of devices small. However, these circuits can be more susceptible to therapeutic doses of radiation such as those used in cancer treatment. The damage can occur when cumulative doses of radiation affect the small silicon and silicon oxide insulators within the transistors.

Therapeutic radiation therapy is administered in one of the following ways:

• Radioactive cobalt
• Linear accelerators
• Betatrons

The linear accelerators and betatrons produce radiation and a strong electromagnetic field.

Pacemaker failures are random. Possible effects include:

• Temporary loss of sensing
• Temporary device inhibition
• Temporary loss of capture
• Temporary increased sensor rate
• Temporary rate changes
• Device reset or reversion to backup VVI pacing

The dose of radiation delivered to a pacemaker is cumulative. You must add all doses a pacemaker has received in its lifetime to determine how much radiation it has received.

No exact radiation amount has been determined to cause malfunction. Individual St. Jude Medical pacemakers have been tested to 3,000 rads, without any adverse effects. Note: 2,000 rads is seldom encountered when the pacemaker is located outside of the irradiated field.

Review Radiation Guidelines [PDF 123KB]

Cardiac Rhythm Management Technical Support.

There is no need to perform a self-test or calibration on a St. Jude Medical programmer. Our programmers perform self-test routines when powered on. The self-test routines check the internal hardware and software and provide the user with an indication that the test was successful. If any portion of the self-test fails, the programmer indicates the reason for the failure and disables the programmer.

If a programmer fails a self-test, turn off the power for approximately 30 seconds. Power on the programmer to perform a new self-test. If the programmer fails the second self-test, return the unit to St. Jude Medical for repair.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Radar used in speed guns has not been reported to cause any interaction with cardiac pacemakers. Recipients of our pacemakers work at airports and on ships where radar is used. To date we have no clinical reports of electromagnetic interference (EMI) with radar. Ground based radar is directed above the horizon to avoid any direct radiation exposure to humans.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Nerve conduction testing shouldn’t damage or reprogram pacemakers. There is potential for a pacemaker to sense the output from test equipment. This may temporarily inhibit the pacemaker. If inhibition occurs, shut off the test equipment to stop the interference. The pacemaker will automatically pace as usual.

If you are undergoing a nerve conduction procedure, be alert for symptoms like those when the pacemaker was implanted (dizziness, light-headedness, and such). If these symptoms occur, stop the procedure.

Physicians and health care professionals may elect to program the pacemaker to a less sensitive setting. Program all sensing configurations to bipolar and decrease the ventricular sensitivity. Select a maximum tracking rate (MTR) that the patient can tolerate with ease.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Pacemaker recipients should not undergo MRI because of the extremely strong magnetic fields generated during the procedure. MRI may impair the normal operation of an implanted pacemaker. A review of literature shows isolated cases in which damage occurred, but this is considered rare.

If an MRI is necessary, the following effects may occur:

• Asynchronous pacing resulting from the extremely strong magnetic field generated by the MRI
• Single beat inhibition of pacing output due to over sensing of the radio frequency field created by the MRI
• High rate pacing due to synchronization with the radio frequency field created by the MRI
• Potential pacemaker component damage due to the magnetic field generated by the MRI
• Lead dislodgment and pacemaker movement within the pocket

Assess the pulse generator function following exposure to MRI and may be compared to previous device assessments if necessary.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Based on information from two manufacturers (Targis™ and Prostratron®), we do not anticipate any damage or reprogramming of our pacemakers due to microwave prostate therapy.

Physicians and health care professionals may elect to program the pacemaker to a less sensitive setting. Program all sensing configurations to bipolar and decrease the ventricular sensitivity. Select a maximum tracking rate (MTR) that the patient can tolerate with ease.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Cardiac pacemakers are prone to possible interference from other sources of electrical equipment, including microwave ovens. Both the microwave and pacemaker industries have made technological advances in the area of shielding. Electrical leakage from newer microwave ovens is minimal and should not affect an implanted pacemaker. The use of a microwave oven that meets U.S. federal safety standards by a person with a pacemaker has not been found to subject the person to any potential harmful problems.

St. Jude Medical does not have control over the type, age, or condition of microwave ovens. However, providing the microwave oven is in proper working order, we do not anticipate any pacemaker interference problems.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Shock wave lithotripsy uses a spark gap or electromagnetic transducer to produce a shock wave for patients with renal calculi (kidney stones).

The pacemaker may sense the electrical signal from a lithotripter as intrinsic heart activity and cause a single beat inhibition of the ventricular output pulse. Single beat inhibition won’t be noticed by the patient.

For Physicians & Health Care Professionals
To minimize potential inhibition, time shock wave delivery synchronously with the patient’s R-wave. Extracorporeal Shock Wave Lithotripsy (ESWL) should be performed in the R-wave triggered mode. ESWL can trigger the atrial output pulse and the subsequent inhibition of the following ventricular pulse. Program dual pacemakers to the VVI or VOO mode prior to ESWL to prevent this occurrence.

ESWL can permanently damage the piezoelectric crystal in an activity sensor based pacemaker if the ESWL focal point is directed towards the pacemaker. Focus the beam at least six inches away from the implanted pacemaker. Program activity sensor based pacemakers to a non-rate responsive pacing mode prior to ESWL therapy.

Perform a thorough assessment of the pulse generator immediately prior to and after exposure to ESWL. This will rule out any device damage. For activity sensor based pacemakers, make sure to assess sensor function after an ESWL procedure. We recommend including a copy of the programmer printouts in the patient’s records.

You may wish to review the following guidelines:

Lithotripsy & Pacemakers [PDF 37KB]

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Latex is not used in any St. Jude Medical products with the exception of four flow directed Pacel Bipolar Pacing Catheters (order numbers: 401761, 401762, 401763, and 401764).

Need additional information? Contact Cardiac Rhythm Management Technical Support.

The LASIK procedure uses light energy, so we do not anticipate any damage to the pacemaker due to this procedure. We have received verbal reports that the LASIK procedure has been performed on pacemaker patients uneventfully.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Treatment should not damage or reprogram St. Jude Medical pacemakers. However, there is the potential for your pacemaker to sense the output from an iontophoresis stimulator and temporarily inhibit the pacemaker or cause asynchronous pacing.

Whenever a current is passed through the body, there is a possibility that the pacemaker can sense this signal. Iontophoresis stimulators produce approximately 1-4 mA of current, which may interact with cardiac pacemakers.

If you decide to proceed with the iontophoresis procedure, be alert for symptoms like those you may have experienced before the pacemaker was implanted (dizziness, light-headedness, and such). If these symptoms occur, discontinue treatment. The symptoms should disappear.

For Physicians & Health Care Professionals
Program pacemakers with impedance based sensors (like minute ventilation or stroke volume for rate responsive pacing) to a non-rate responsive mode to prevent increased pacing rates during iontophoresis treatment.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Application of an additional current source can potentially cause a rate increase in impedance-based pacemakers. Generally, this rate increase is temporary and pacing returns to a normal rate once the interference signal is removed. Any rate increase will occur within the programmed minimum and maximum sensor rate range set by the clinician. Turning the ECG impedance monitoring to off can prevent interference.

Most pacemaker manufacturers (for their newer physiologic pacemakers) use an injected current to determine the impedance for rate responsive pacing or for stroke volume determination. Any additional electrical current applied to the body can interfere with these pacing algorithms. Common electrical current therapies or diagnostic sources include:

• Transelectrical nerve stimulation (TENS) units
• Cautery (electrical surgery units)
• DC ablation
• Cardioversion
• Diathermy
• Electro-acupuncture
• Electroconvulsive shock therapy

Some ECG monitors inject a current signal to measure impedance. These include ECG monitors that inject a current to measure the respiratory rate or to detect a disconnected surface lead. Such monitors can potentially interfere with impedance based pacemakers.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

There is a slight possibility that a pacemaker may mistake the energy from a security gate as your heart’s natural rhythm and withhold its pacing output for a single beat. Airport security gates emit radio frequency energy that is reflected back to the gates by metal objects. The energy emitted by the gates is localized to the area between and around the gates, so the single-beat inhibition would occur only for the duration that you remain in the energy field.

Your pacemaker won’t be damaged or reprogrammed and we don’t expect you to experience any problems.

Tips

• Walk through the gates at your normal pace
• Do not lean against the gates
• Be sure to carry your patient ID card with you when you travel. This will help airport personnel verify that you have a pacemaker

Need additional information? Contact Cardiac Rhythm Management Technical Support.

The house arrest monitor (Digital Products Corp.) has a radio frequency power of 150 mW at a frequency of 314 MHz. Based on this information, we do not anticipate any damage or reprogramming of your pacemaker. However, since the house arrest monitor is worn on the wrist or ankle, the wrist transmitter may come within an inch of the pacemaker. The potential for pacemaker inhibition exists. We recommend placing the monitor around your ankle.

St. Jude Medical has not completed testing on possible interactions between pacemakers and the house arrest monitoring system. You physician can determine if there is any interaction.

For Physicians & Health Care Professionals
ECG monitoring of the patient with a house arrest monitor will help to identify if any interference is present. Based on the patient evaluation, heart condition, testing, and the information shared here, you can make a recommendation for use of the house arrest monitor.

Need additional information? Contact Cardiac Rhythm Management Technical Support.

Yes. The use of ham radio or CB radio should not damage or reprogram St. Jude Medical pacemakers. There is a remote possibility that the microphone or transmitter may cause a single-beat inhibition.

We don’t anticipate any interaction, but your physician or health care professional may elect to program the pacemaker to a less sensitive setting. If you notice interference, verify that the antenna is at least 3 feet away for portable units and 10 feet away for base stations.

All of our currently manufactured pacemakers have feed through filters that are highly effective in the mega-Hertz frequency range. The effectiveness of this filtering provides an additional level of safety for people with St. Jude Medical pacemakers.

Need additional information? Contact Cardiac Rhythm Management Technical Support.