Pacemaker which adapts to minimize current drain and provide desired capture safety margin
US5447525A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1993 |
| Grant date | Sep 5, 1995 |
| Priority date | — |
| Expiry date | Sep 15, 2013 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61N1/3708
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A cardiac pacemaker improves battery longevity by automatically providing a safe threshold and an associated pulse width leading to minimum current drain. The pacemaker stores a matrix of current drain characteristics for all of the possible pulse width-voltage pairs, and a revisable strength-duration curve for a patient. Either periodically or as a result of a loss-of-capture episode--whichever occurs first--the pacemaker calculates for each possible pulse width, a new threshold value based upon a measured rheobase and a derived chronaxie. Each threshold is multiplied by a predetermined safety margin. The pacemaker chooses as the pacing stimulation signal, the voltage-pulse width pair having the lowest associated current drain, and satisfying the desired safety margin.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.