Pacemaker manufacturer | Magnet mode designation | Explanation | |
Biotronik | AUTO (DEFAULT) | If normal conditions, 10 asynchronous events at 90 bpm, then returns to original programmed mode (ie, synchronous pacing) at the lower rate limit. If battery is at ERI, 10 asynchronous events at 80 bpm in VOO mode, then either VDD (dual-chamber) or VVI (single-chamber) with pacing at 11% below the lower rate limit. For any dual-chamber mode, the AVd shortens to 100 milliseconds for the 10 asynchronous events. | |
ASYNCH | Asynchronous pacing at 90 bpm if normal conditions. At ERI, 80 bpm (single-step change) in VOO mode regardless of original programming. For any dual-chamber pacing mode, the AVd shortens to 100 milliseconds while the magnet is in place. | ||
SYNCH | If normal conditions, pacing in original programmed mode, without rate responsiveness. Pacing is at lowest available rate (LRL, sleep rate, or hysteresis rate). If battery is at ERI, then either VDD (dual chamber) or VVI (single chamber) with pacing at 11% below the lower rate limit. | ||
Boston Scientific (includes Guidant Medical CPI) | ASYNCH (DEFAULT) | If normal conditions, asynchronous pacing with 100 millisecond AVd at 100 bpm. If ERI, 85 bpm (single-step change). The Insignia and Altrua models have an intermediate step (90 bpm) at ERN. Most models shorten the pulse width to 50% on the third paced ventricular event (TMT). For Triumph and Prelude models, refer to Medtronic pacemakers, below. | |
OFF | No change; magnet is ignored. OFF is also the magnet mode after a "power on reset," or activation of "safety core," which can occur secondary to EMI. | ||
EGM mode | No change in pacing. Magnet application initiates data collection. | ||
Intermedics (purchased by Guidant in 1998, now Boston Scientific, but special programmer needed) | Five asynchronous events at 90 bpm (regardless of battery voltage), then 60 additional asynchronous events at LRL if normal conditions, 90 bpm if ERI, and 80 bpm if EOL. The fifth paced event is emitted at 50% of the originally programmed pulse width (TMT). After the 64th asynchronous event, the magnet is ignored. | ||
Medtronic | Conventional transvenous pacemakers (including cardiac resynchronization therapy – pacemakers) | Asynchronous pacing based on programmed mode at 85 bpm if normal conditions*, 65 bpm if at ERI. | |
Leadless intra-cardiac pacemakers (ie, “Micra” and “Micra AV”) | No magnet response. | ||
MicroPort (Sorin / ELA Medical) | Asynchronous pacing at 96 bpm gradually declining to 80 bpm at ERI. Sorin/ELA pacemakers take eight additional pacing cycles (the final two cycles are at LRL with long AVd) upon magnet removal. | ||
Abbott (St. Jude Medical [SJM], Pacesetter) | "SJM" radiograph logo; standard transvenous pacemaker | Battery test (DEFAULT) | Asynchronous pacing at 100 bpm (older models 98.6 bpm) gradually decreasing to 85 bpm (older models 86.3) at ERI. |
OFF | No magnet response. | ||
Event snapshots | No change in pacing. Magnet application causes pacemaker to collect data. Identity and Entity models lack this feature. | ||
Event snapshots + battery test | For a magnet placed on the device for two seconds, pacing mode and rate are unchanged, and the device stores an electrogram. If the magnet is placed for =5 seconds, the battery test mode (refer to above) is activated. Identity and Entity models lack this feature. | ||
Pacesetter radiograph logo; standard transvenous pacemaker | Battery test (DEFAULT) | Asynchronous pacing, and the rate depends upon specific model. In general, a pacing rate of less than 90 bpm should prompt further evaluation. | |
OFF | No magnet response. | ||
VARIO mode (present in some models) | VARIO results in a series of 32 asynchronous pacing events. The rate of the first 16 paces reflects battery voltage, gradually declining from 100 bpm to 85 bpm at ERI. The next 15 paces are used to document ventricular pacing capture safety margin. The rate will be 119 bpm with gradually declining pacing voltage. The 16th pace of this group is at no output. The next pace restarts the 32-event sequence. The 32-event sequence repeats while the magnet remains in place. | ||
"Nanostim" leadless intra-cardiac pacemaker | On (DEFAULT) | Asynchronous pacing at 100 bpm for eight cycles, then 90 bpm if normal conditions; 65 bpm if ERI. | |
OFF | No magnet response. |
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