US4091818A
Expired / Lapsed
US
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Cardiac pacing apparatus with electromagnetic interference protection
Assignee: Pennsylvania Research Corp
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Filing: 1976-08-03
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Granted: 1978-05-30
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Expires: 1996-08-03
Abstract
Abstract A cardiac pacing apparatus of the type having a first signal processing channel which functions in the demand mode is disclosed including a second signal processing channel for detecting electromagnetic interference and causing the pacing apparatus to revert to a safe operating rate in the presence of such interference. In a preferred embodiment, the second signal processing channel has an enhanced high-frequency response with respect to that of the first signal processing channel in order to optimize interference detection. The second channel may receive an input from either a conventional cardiac sensing and pacing electrode, or else a second electrode, remote from the heart, may be provided for interference detection. When electromagnetic interference is detected by the second signal processing channel, an override of the conventional demand pacer inhibit function occurs and the pacing apparatus is switched to a safe operating rate, which may be either an appropriate predetermined fixed rate or a rate-limited rate synchronous with the detected electromagnetic interference. In an alternate embodiment, the gain of the second signal processing channel is reduced with respect to that of the first channel, and the pacing apparatus is switched to a safe operating rate upon the detection of electromagnetic interference having an amplitude level above that of natural cardiac signals.
Inventors
- 👤 Robert R. Brownlee
- 👤 G. Frank O. Tyers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:10
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/18; A61N1/32; A61N1/36; A61N1/362; A61N1/37; G; G01; G01R; G01R29/00; G01R29/08; G01R29/0807; G01R29/0814; A61N1/3718
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
265 words
An improved cardiac pacing apparatus of the type having first electrode means for sensing and pacing connectable to the heart; a first signal processing channel including means for generating artificial heart stimulating pulses at a predetermined rate and applying said pulses to said first electrode means, first bandpass amplifier means having an input connected to said first electrode means for detecting natural heart stimulating pulses, said artificial heart stimulating pulses and electromagnetic interference, and producing a detection signal having a rate in accordance therewith, and first control means, responsive to said detection signal and having an output operatively coupled to said means for generating artificial heart stimulating pulses, for continuously inhibiting the generation of said artificial pulses whenever the rate of said detection signal exceeds said predetermined rate; wherein the improvement comprises a second signal processing channel including: second bandpass amplifier means for detecting electromagnetic interference and producing a blocking signal in accordance therewith, said second bandpass amplifier means having an enhanced high frequency response with respect to the high frequency response of said first bandpass amplifier means to enhance the relative sensitivity of said second bandpass amplifier means to the higher frequency spectral components of said electromagnetic interference; and second control means, responsive to said blocking signal and having an output operatively coupled to said first control means, for preventing said first control means from inhibiting the generation of said artificial heart stimulating pulses whenever said blocking signal is produced, thereby causing the generation of artificial heart stimulating pulses at said predetermined rate whenever electromagnetic interference is detected by said second bandpass amplifier means.
Claim 2
Dependent Claim
265 words
An improved cardiac pacing apparatus of the type having first electrode means for sensing and pacing connectable to the heart; a first signal processing channel including means for generating artificial heart stimulating pulses at a predetermined rate and applying said pulses to said first electrode means, first bandpass amplifier means having an input connected to said first electrode means for detecting natural heart stimulating pulses, said artificial heart stimulating pulses and electromagnetic interference, and producing a detection signal having a rate in accordance therewith, and first control means, responsive to said detection signal and having an output operatively coupled to said means for generating artificial heart stimulating pulses, for continuously inhibiting the generation of said artificial pulses whenever the rate of said detection signal exceeds said predetermined rate; wherein the improvement comprises a second signal processing channel including: second bandpass amplifier means for detecting electromagnetic interference and producing a blocking signal in accordance therewith, said second bandpass amplifier means having an enhanced high frequency response with respect to the high frequency response of said first bandpass amplifier means to enhance the relative sensitivity of said second bandpass amplifier means to the higher frequency spectral components of said electromagnetic interference; and second control means, responsive to said blocking signal and having an output operatively coupled to said first control means, for preventing said first control means from inhibiting the generation of said artificial heart stimulating pulses whenever said blocking signal is produced, thereby causing the generation of artificial heart stimulating pulses at said predetermined rate whenever electromagnetic interference is detected by said second bandpass amplifier means.
Claim 3
Dependent Claim
66 words
An improved cardiac pacing apparatus as in claim 1, wherein said second bandpass amplifier means has a detecting input connected to said first electrode means in common with said first bandpass amplifier means, and wherein said second bandpass amplifier means has a reduced low frequency response with respect to said first bandpass amplifier means to render said second amplifier means substantially insensitive to natural cardiac signals.
Claim 4
Dependent Claim
32 words
An improved cardiac pacing apparatus as in claim 1, further comprising second electrode means remote from the heart for detecting electromagnetic interference and providing an input to said second bandpass amplifier means.
Claim 5
Dependent Claim
83 words
An improved cardiac pacing apparatus as in claim 1, wherein said means for generating artificial heart stimulating pulses at a predetermined rate comprises rate control means operatively coupled to the output of said second control means for selectably and momentarily switching said predetermined rate from a first, lower rate in the absence of an electromagnetic interference detection to a second, higher rate whenever said second control means is activated by a blocking signal from said second bandpass amplifier means for detecting electromagnetic interference.
Claim 6
Dependent Claim
277 words
An improved cardiac pacing apparatus of the type having a first electrode means for sensing and pacing connectable to the heart; a first signal processing channel including means for generating artificial heart stimulating pulses at a predetermined rate and applying said pulses to said first electrode means, first bandpass amplifier means having an input connected to said first electrode means for detecting natural heart stimulating pulses, said artificial heart stimulating pulses and electromagnetic interference, and producing a detection signal having a rate in accordance therewith, and first control means, responsive to said detection signal and having an output operatively coupled to said means for generating artificial heart stimulating pulses, for continuously inhibiting the generation of said artificial pulses whenever the rate of said detection signal exceeds said predetermined rate; wherein the improvement comprises a second signal processing channel including: second bandpass amplifier means for detecting electromagnetic interference and producing a second detection signal in accordance therewith, said second bandpass amplifier means having an enhanced high frequency response with respect to the high frequency response of said first bandpass amplifier means to enhance the relative sensitivity of said second bandpass amplifier means to the higher frequency spectral components of said electromagnetic interference; and second control means, responsive to said second detection signal and having a rate-limited output operatively coupled to said means for generating artificial heart stimulating pulses, for triggering said generating means at a rate in accordance with the rate of said second detection signal but at a rate no higher than a predetermined maximum rate, thereby causing the generation of rate-limited artificial heart stimulating pulses whenever electromagnetic interference is detected by said second bandpass amplifier means.
Claim 7
Dependent Claim
277 words
An improved cardiac pacing apparatus of the type having a first electrode means for sensing and pacing connectable to the heart; a first signal processing channel including means for generating artificial heart stimulating pulses at a predetermined rate and applying said pulses to said first electrode means, first bandpass amplifier means having an input connected to said first electrode means for detecting natural heart stimulating pulses, said artificial heart stimulating pulses and electromagnetic interference, and producing a detection signal having a rate in accordance therewith, and first control means, responsive to said detection signal and having an output operatively coupled to said means for generating artificial heart stimulating pulses, for continuously inhibiting the generation of said artificial pulses whenever the rate of said detection signal exceeds said predetermined rate; wherein the improvement comprises a second signal processing channel including: second bandpass amplifier means for detecting electromagnetic interference and producing a second detection signal in accordance therewith, said second bandpass amplifier means having an enhanced high frequency response with respect to the high frequency response of said first bandpass amplifier means to enhance the relative sensitivity of said second bandpass amplifier means to the higher frequency spectral components of said electromagnetic interference; and second control means, responsive to said second detection signal and having a rate-limited output operatively coupled to said means for generating artificial heart stimulating pulses, for triggering said generating means at a rate in accordance with the rate of said second detection signal but at a rate no higher than a predetermined maximum rate, thereby causing the generation of rate-limited artificial heart stimulating pulses whenever electromagnetic interference is detected by said second bandpass amplifier means.
Claim 8
Dependent Claim
64 words
An improved cardiac pacing apparatus as in claim 5, wherein said second bandpass amplifier means has a detecting input connected to said first electrode means in common with said first bandpass means, and wherein second bandpass amplifier means has a reduced low frequency response with respect to said first bandpass amplifier means to render said second amplifier means substantially insensitive to natural cardiac signals.
Claim 9
Dependent Claim
32 words
An improved cardiac pacing apparatus as in claim 5, further comprising second electrode means remote from the heart for detecting electromagnetic interference and providing an input to said second bandpass amplifier means.
Claim 10
Dependent Claim
272 words
An improved cardiac pacing apparatus of the type having first electrode means for sensing and pacing connectable to the heart; a first signal processing channel including means for generating artificial heart stimulating pulses at a predetermined rate and applying said pulses to said first electrode means, first amplifier means having an input connected to said first electrode means for detecting natural heart stimulating pulses, said artificial heart stimulating pulses and electromagnetic interference, and producing a detection signal having a rate in accordance therewith, and first control means, responsive to said detection signal and having an output operatively coupled to said means for generating artificial heart stimulating pulses, for continuously inhibiting the generation of said artificial pulses whenever the rate of said detection signal exceeds said predetermined rate; wherein the improvement comprises a second signal processing channel including: second amplifier means, for detecting electromagnetic interference having an amplitude level above that of natural heart stimulating pulses and producing a blocking signal in accordance therewith, the gain of said second amplifier means being reduced with respect to the gain of said first amplifier means sufficiently to render said second signal processing channel insensitive to natural heart stimulating pulses; and second control means, responsive to said blocking signal and having an output operatively coupled to said first control means, for preventing said first control means from inhibiting the generation of said artificial heart stimulating pulses whenever said blocking signal is produced, thereby causing the generation of artificial heart stimulating pulses at said predetermined rate whenever electromagnetic interference having an amplitude level above that of natural heart stimulating pulses is detected by said second amplifier means.
Claim 11
Dependent Claim
272 words
An improved cardiac pacing apparatus of the type having first electrode means for sensing and pacing connectable to the heart; a first signal processing channel including means for generating artificial heart stimulating pulses at a predetermined rate and applying said pulses to said first electrode means, first amplifier means having an input connected to said first electrode means for detecting natural heart stimulating pulses, said artificial heart stimulating pulses and electromagnetic interference, and producing a detection signal having a rate in accordance therewith, and first control means, responsive to said detection signal and having an output operatively coupled to said means for generating artificial heart stimulating pulses, for continuously inhibiting the generation of said artificial pulses whenever the rate of said detection signal exceeds said predetermined rate; wherein the improvement comprises a second signal processing channel including: second amplifier means, for detecting electromagnetic interference having an amplitude level above that of natural heart stimulating pulses and producing a blocking signal in accordance therewith, the gain of said second amplifier means being reduced with respect to the gain of said first amplifier means sufficiently to render said second signal processing channel insensitive to natural heart stimulating pulses; and second control means, responsive to said blocking signal and having an output operatively coupled to said first control means, for preventing said first control means from inhibiting the generation of said artificial heart stimulating pulses whenever said blocking signal is produced, thereby causing the generation of artificial heart stimulating pulses at said predetermined rate whenever electromagnetic interference having an amplitude level above that of natural heart stimulating pulses is detected by said second amplifier means.
Claim 12
Dependent Claim
282 words
An improved cardiac pacing apparatus of the type having first electrode means for sensing and pacing connectable to the heart; a first signal processing channel including means for generating artificial heart stimulating pulses at a predetermined rate and applying said pulses to said first electrode means, first amplifier means having an input connected to said first electrode means for detecting natural heart stimulating pulses, said artificial heart stimulating pulses and electromagnetic interference, and producing a detection signal having a rate in accordance therewith, and first control means, responsive to said detection signal and having an output operatively coupled to said means generating artificial heart stimulating pulses, for continuously inhibiting the generation of said artificial pulses whenever the rate of said detection signal exceeds said predetermined rate; wherein the improvement comprises a second signal processing channel including: second amplifier means for detecting electromagnetic interference having an amplitude level above that of natural heart stimulating pulses and producing a second detection signal in accordance therewith, the gain of said second amplifier means being reduced with respect to the gain of said first amplifier means sufficiently to render said second signal processing channel insensitive to natural heart stimulating pulses; and second control means, responsive to said second detection signal and having a rate-limited output operatively coupled to said means for generating artificial heart stimulating pulses, for triggering said generating means at a rate in accordance with the rate of said second detection signal but at a rate no higher than a predetermined maximum rate, thereby causing the generation of rate-limited artificial heart stimulating pulses whenever electromagnetic interference having an amplitude level above that of natural heart stimulating pulses is detected by said second amplifier means.
Claim 13
Dependent Claim
282 words
An improved cardiac pacing apparatus of the type having first electrode means for sensing and pacing connectable to the heart; a first signal processing channel including means for generating artificial heart stimulating pulses at a predetermined rate and applying said pulses to said first electrode means, first amplifier means having an input connected to said first electrode means for detecting natural heart stimulating pulses, said artificial heart stimulating pulses and electromagnetic interference, and producing a detection signal having a rate in accordance therewith, and first control means, responsive to said detection signal and having an output operatively coupled to said means generating artificial heart stimulating pulses, for continuously inhibiting the generation of said artificial pulses whenever the rate of said detection signal exceeds said predetermined rate; wherein the improvement comprises a second signal processing channel including: second amplifier means for detecting electromagnetic interference having an amplitude level above that of natural heart stimulating pulses and producing a second detection signal in accordance therewith, the gain of said second amplifier means being reduced with respect to the gain of said first amplifier means sufficiently to render said second signal processing channel insensitive to natural heart stimulating pulses; and second control means, responsive to said second detection signal and having a rate-limited output operatively coupled to said means for generating artificial heart stimulating pulses, for triggering said generating means at a rate in accordance with the rate of said second detection signal but at a rate no higher than a predetermined maximum rate, thereby causing the generation of rate-limited artificial heart stimulating pulses whenever electromagnetic interference having an amplitude level above that of natural heart stimulating pulses is detected by said second amplifier means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-29 | 1981-11-28 | 1982-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-29 | 1985-11-28 | 1986-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-29 | 1989-11-28 | 1990-05-30 | $7700.00 | Window Closed / Lapsed |