Optimal pulse defibrillator
US5645573A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Jul 8, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61N1/3912
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
The model that is developed in the present invention is based upon the pioneering neurophysiological models of Lapicque and Weiss. The present model determines mathematically the optimum pulse duration, d.sub.p, for a truncated capacitor-discharge waveform employed for defibrillation. The model comprehends the system time constant, RC, where R is tissue resistance and C is the value of the capacitor being discharged, and also the chronaxie time, d.sub.c, defined by Lapicque, which is a characteristic time associated with the heart. The present model and analysis find the optimum pulse duration to be d.sub.p =(0.58)(RC+d.sub.c). Taking the best estimate of the chronaxie value from the literature to be 2.7 ms, permits one to rewrite the optimum pulse duration as d.sub.p =(0.58)RC+1.6 ms. The present invention makes use of the mathematical definition of optimum pulse duration by storing in the control circuitry of the defibrillation system the actual measured value of the particular capacitor incorporated in the system. The optimized-pulse prescription of this invention can be applied to a monophasic waveform, or to either or both of the phases of a biphasic waveform.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.