US4821735A
Expired / Lapsed
US
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Method and apparatus for detecting myocardial ischemia
Assignee: Itamar Medical Ltd
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Filing: 1988-02-11
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Granted: 1989-04-18
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Expires: 2008-02-11
Abstract
Abstract An apparatus and method for detecting myocardial ischemia in a subject monitors the systemic vascular resistance of the subject and detects the presence of myocardial ischemia when the systemic vascular resistance increases by at least sixty percent over a base line value. Particular apparatus describe providing a measurement corresponding to the systemic vascular resistance of the cardiovascular system. A particular invasive pressure measuring apparatus uses a flexible catheter tube insertable into the artery of the subject and a micro-manometer embedded into the outer face of the wall of the catheter tube. The outer face of the embedded micro-manometer is directly exposed to the blood in an artery and the inner face of the embedded micro-manometer is covered by the inner face of the catheter tube wall.
Inventors
- 👤 Daniel Goor
- 👤 Raphael Mohr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 05:54
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/02; A61B5/021; A61B5/0215; A61B5/72; A61B5/7235; A61B5/7239
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
52 words
A method for detecting myocardial ischemia in a subject comprising the steps of: monitoring the systemic vascular resistance of the subject; and detecting the presence of myocardial ischemia in a subject when the monitored systemic vascular resistance of the subject increases by at least 60%, thereby indicating the presence of myocardial ischemia.
Claim 2
Independent Claim
52 words
A method for detecting myocardial ischemia in a subject comprising the steps of: monitoring the systemic vascular resistance of the subject; and detecting the presence of myocardial ischemia in a subject when the monitored systemic vascular resistance of the subject increases by at least 60%, thereby indicating the presence of myocardial ischemia.
Claim 3
Dependent Claim
125 words
The method according to claim 1, wherein the monitoring step comprises the steps of: A. detecting the arterial pressure of the subject and generating in response thereto a blood pressure signal having a waveform in accordance with the detected arterial pressure; B. differentiating said blood pressure signal to produce a dP/dt signal having a waveform varying in accordance with the rate at which the blood pressure signal varies; C. detecting the peak of said dP/dt signal to determine the peak dP/dt; D. determining a value which is substantially equal to the arterial pressure at the time of said peak dP/dt; E. dividing said latter value by said peak dP/dt signal, which thereby produces a measurement corresponding to the systemic vascular resistance of said cardiovascular system.
Claim 4
Dependent Claim
15 words
The method according to claim 2, wherein the pressure of the femoral artery is detected.
Claim 5
Dependent Claim
21 words
The method according to claim 1, wherein said monitoring step includes the step of detecting the pressure of the femoral artery.
Claim 6
Dependent Claim
48 words
Apparatus for detecting myocardial ischemia in a subject comprising: monitoring means for monitoring the systemic vascular resistance of the subject, and indicator means for detecting the presence of myocardial ischemia in the subject increases by at least 60%, thereby indicating the presence of myocardial ischemia in the subject.
Claim 7
Dependent Claim
48 words
Apparatus for detecting myocardial ischemia in a subject comprising: monitoring means for monitoring the systemic vascular resistance of the subject, and indicator means for detecting the presence of myocardial ischemia in the subject increases by at least 60%, thereby indicating the presence of myocardial ischemia in the subject.
Claim 8
Dependent Claim
133 words
The apparatus according to claim 5 wherein said monitoring means comprises: A. means for detecting the arterial pressure of the subject and for generating in response thereto a blood pressure signal having a waveform varying in accordance with the detected arterial pressure; B. means for differentiating said blood pressure signal to produce a dP/dt signal having a waveform varying in accordance with the rate at which the blood pressure signal varies; C. means for detecting the peak of said dP/dt signal to determine the peak dP/dt; D. means for determining a value which is substantially equal to the arterial pressure at the time of said peak dP/dt; and E. means for dividing said latter value by said peak dP/dt, thereby producing a measurement corresponding to the systemic vascular resistance of said cardiovascular system.
References Cited (Backward Citations)
US4203451A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-17 | 1992-10-17 | 1993-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-17 | 1996-10-17 | 1997-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-17 | 2000-10-17 | 2001-04-18 | $7700.00 | Window Closed / Lapsed |