Closed-chest cardiac stimulation with a pulsed magnetic field |
| |
Authors: | G A Mouchawar Dr J D Bourland J A Nyenhuis L A Geddes K S Foster J T Jones G P Graber |
| |
Institution: | (1) Hillenbrand Biomedical Engineering Center, School of Electrical Engineering, Purdue University, 47907 West Lafayette, IN, USA |
| |
Abstract: | Magnetic stimulators, used medically, generate intense rapidly changing magnetic fields, capable of stimulating nerves. Advanced
magnetic resonance imaging systems employ stronger and more rapidly changing gradient fields thant those used previously.
The risk of provoking cardiac arrhythmias by these new devices is of concern. In the paper, the threshold for cardiac stimulation
by an externally-applied magnetic field is determined for 11 anaesthetised dogs. Two coplanar coils provide the pulsed magnetic
field. An average energy of approximately 12kJ is required to achieve closed-chest magnetically induced ectopic beats in the
17–26kg dogs. The mean peak induced electric field for threshold stimulation is 213 Vm
−1
for a 571 μs damped sine wave pulse. Accounting for waveform efficacy and extrapolating to long-duration pulses, a threshold
induced electric field strength of approximately 30 Vm
−1
for the rectangular pulse is predicted. It is now possible to establish the margin of safety for devices that use pulsed
magnetic fields and to design therapeutic devices employing magnetic fields to stimulate the heart. |
| |
Keywords: | Magnetic stimulation Transchest magnetic cardiac pacing |
本文献已被 SpringerLink 等数据库收录! |
|