Method and apparatus for calculating and monitoring the impedance of an implanted pacemaker lead from a surface ECG of a pacemaker pulse
US5649969A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 9, 1996 |
| Grant date | Jul 22, 1997 |
| Priority date | — |
| Expiry date | Aug 9, 2016 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B2018/00875
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A method and apparatus for calculating and monitoring the impedance of an implanted pacemaker lead, and in particular to such a method and apparatus for monitoring the impedance to determine whether a lead fault, such as a lead rupture or a lead dislocation, has occurred. In order to avoid reprogramming the implanted pacemaker to deliver a pulse having known parameters in order to permit an impedance measurement to be made, the method and apparatus operate on the basis of the system formed by the pulse generator, the electrode leads and body tissue being considered to behave as an RC circuit, with the pulse generator emitting an ideal square wave pulse which then exhibits an exponential decay in the body tissue having a decay time constant associated therewith. From surface ECG measurements, the decay time constant is estimated, and since the capacitance of the pulse generator is known, the lead impedance can then be calculated. A determination can then be made whether the calculated lead impedance deviates from the nominal lead impedance to such an extent that a malfunction is assumed to be present.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.