Guidelines for Magnet Checks on Permanent Pacemakers
For patients with permanent pacemakers (PPMs), magnet checks should be performed twice in the first 6 months after implantation and then once every 12 months for single-chamber pacemakers, or twice in the first 6 months and then once every 6 months for dual-chamber pacemakers. 1
Purpose of Magnet Checks
Magnet checks are essential for evaluating pacemaker function and ensuring patient safety. When a magnet is applied to a pacemaker, it triggers the device to pace in an asynchronous mode, allowing clinicians to assess:
- Effective capture verification - Confirming that the pacemaker effectively captures the appropriate chamber(s)
- Magnet rate assessment - Evaluating battery status by comparing current magnet rate with previous values
- Pulse width evaluation - For pacemakers using pulse width as an elective replacement indicator
- Threshold testing - If the device has threshold assessment capabilities
- AV interval changes - For dual-chamber pacemakers that alter AV intervals during magnet application
Proper Technique for Magnet Checks
Before the Check:
- Obtain baseline ECG to determine if the patient is pacemaker-dependent
- Review previous magnet check results for comparison
- Ensure appropriate monitoring equipment is available
During the Check:
- Apply the magnet directly over the pacemaker generator
- Record ECG strips of both:
- Non-magnet (free-running) ECG assessment (6-9 seconds)
- Magnet-applied ECG assessment (6-9 seconds)
- Observe for appropriate asynchronous pacing response
Documentation Requirements:
- Whether the patient displays intrinsic rhythm or is continuously/intermittently paced
- Underlying atrial mechanism (sinus rhythm, atrial fibrillation, etc.)
- Sensing function for relevant chambers
- Effective capture verification
- Current magnet rate compared to previous values
- Any changes in pulse width or other elective replacement indicators
Special Considerations
Pacemaker-Dependent Patients
For pacemaker-dependent patients undergoing procedures with potential electromagnetic interference:
- Reprogram to an asynchronous mode (VOO or DOO) before the procedure 1
- Continuous ECG monitoring is mandatory
- Have temporary pacing equipment immediately available
Magnet Response Variations
- Magnet response varies by manufacturer and can be affected by programming and battery life 1
- Some pacemakers may have no magnet response
- The magnet rate may be excessive for some patients
Potential Complications
Rare but serious complications can occur with magnet application:
- Prolonged pacemaker inhibition in pacemaker-dependent patients 2
- Inappropriate programming changes
- Inaccurate assessment if magnet is improperly positioned
Efficiency Considerations
A 2014 study found that a magnet check alone may be sufficient for most post-implantation assessments, as it provides the most essential data (capture verification) without requiring time-consuming programmer interrogation 3. However, this approach should be balanced with the more comprehensive assessment guidelines established by professional societies.
Frequency of Monitoring
The Health Care Financing Administration (now Centers for Medicare and Medicaid Services) recommends:
- Single-chamber pacemakers: Twice in first 6 months, then once every 12 months
- Dual-chamber pacemakers: Twice in first 6 months, then once every 6 months 1
Additional unscheduled checks may be necessary if the patient experiences symptoms suggesting rhythm or device function alteration.
Emerging Technologies
Remote monitoring systems are increasingly replacing traditional transtelephonic monitoring (TTM) for pacemaker follow-up. These systems use bidirectional telemetry with encrypted radiofrequency signals to allow comprehensive device assessment without in-person visits 1. However, magnet checks remain an important component of comprehensive pacemaker management.
By following these guidelines for magnet checks, clinicians can ensure optimal pacemaker function and enhance patient safety while efficiently utilizing healthcare resources.