Method and apparatus for variable rate cardiac stimulation
US5725561A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 1995 |
| Grant date | Mar 10, 1998 |
| Priority date | — |
| Expiry date | Jun 9, 2015 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61N1/368
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A method and apparatus for variable rate cardiac stimulation, wherein sudden drops in the rate of delivery of stimulation pulses are avoided by means of rate smoothing and peak rate support functions. In one embodiment, circuitry in a cardiac pulse generator detects atrial events and maintains an updated value of the A-A time intervals between certain atrial events. If a preset ratio or total of these A-A intervals are found to have been shorter than the updated value by at a least a predetermined amount of time, a rate smoothing function is activated wherein the rate of delivery of stimulating pulses is prevented from changing, from cycle to cycle, by more than a predetermined maximum amount. A peak rate support function preferably employs the same updated value in the computation of "escape" intervals. Following the latest A-A interval, if that A-A interval is less than the updated value, then the updated value is used as the new escape interval. If the latest A-A interval is greater than or equal to the updated value but less than the previous updated value, the current escape interval is used as the new escape interval. If the latest A-A interval is less than both the previous …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.