US4716904A
Expired / Lapsed
US
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Heart output and circulatory impedance measuring method and apparatus
Assignee: University of Pittsburgh
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Filing: 1986-06-23
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Granted: 1988-01-05
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Expires: 2006-06-23
Abstract
Abstract The invention shows a heart output and circulatory impedance measuring med and associated apparatus based on consecutive subtraction and synchronous summation of digitized ventriculographic images which effectively distinguishes between the motion resulting from contraction of the heart, and the motion resulting from actual displacement or physical movement of the heart back and forth within the chest cavity. From these data is computed a decrement in ventricular volume yielding, in time with subsequent images, the amount of blood ejected from the ventricle that represents the flow. By simultaneously recording the ventricular pressure and by synchronously dividing the pressure by the flow, ventricular load impedance is obtained.
Inventors
- 👤 Frank Meno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:29
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/50; A61B6/504; A61B5/00; A61B5/02; A61B5/026; A61B5/029; A61B6/48; A61B6/481; A61B6/507; A61B6/503
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
101 words
A method of measuring heart output comprising pulsing X-ray beams through a heart chamber containing a contrast medium and blood, detecting the portion of said X-rays not absorbed by said heart and chest, converting said detected X-rays into electrical signals, effecting subtraction of said signals detected at one time from those of another time, and summing the resulting pixel values, whereby said signals relating to heart displacement will be cancelled and said electrical signals relating to heart contraction will remain, and converting said heart contraction signals into a corresponding volume of blood pumped by said heart in a predetermined time interval.
Claim 2
Independent Claim
101 words
A method of measuring heart output comprising pulsing X-ray beams through a heart chamber containing a contrast medium and blood, detecting the portion of said X-rays not absorbed by said heart and chest, converting said detected X-rays into electrical signals, effecting subtraction of said signals detected at one time from those of another time, and summing the resulting pixel values, whereby said signals relating to heart displacement will be cancelled and said electrical signals relating to heart contraction will remain, and converting said heart contraction signals into a corresponding volume of blood pumped by said heart in a predetermined time interval.
Claim 3
Dependent Claim
17 words
The method of claim 1 including effecting pixel thresholding and said subtraction and summation by computer means.
Claim 4
Dependent Claim
19 words
The method of claim 2 including subsequent to said subtraction and pixel thresholding and summation, displaying the results thereof.
Claim 5
Dependent Claim
40 words
The method of claim 1 including employing said method to determine ventricular volume by employing an approximation of a series of ellipses having axes A, B and the series having a height C, proportional to the number of elliptical segments.
Claim 6
Dependent Claim
112 words
The method of claim 4 including determining the reduction in volume of the heart by the relationship ##EQU5## wherein dV t =the reduction in heart volume during the time t and (t-1); t=the instant of the image I n ; t-1=the time instant of the image I n-1 ; F=a calibration factor that relates pixel size to heart size in the image; π=3.14; A k and B k =the axes A and B of the ellipses at the level k coinciding with the projection planes; C=the length of the ventricle; dA, dB, dC each represent the differences in axes A, B and C, respectively, during the time interval between t-1 and t.
Claim 7
Dependent Claim
24 words
The method of claim 5 including pulsing said X-ray beams at a rate of about 15 to 60 pulses/sec each lasting a few milliseconds.
Claim 8
Dependent Claim
16 words
The method of claim 5 including computing said heart contraction volume at one per image frame.
Claim 9
Dependent Claim
38 words
The method of claim 1 including employing said method to determine ventricular volume by employing an approximation of a series of circles making the axes A and B of equal length and the series having a height C.
Claim 10
Dependent Claim
86 words
Apparatus for determining heart output comprising X-ray source means for providing at least one pulsed source of X-rays impinging on said heart, detection means for receiving said X-rays from said heart, processor means for creating digital or analog signals related to heart contractions at different times, and said processor means having means for substracting and summing said signals to effect separation of heart displacement signals from heart contraction signals, and conversion means for changing said heart contraction signals into information which relates to determining heart output.
Claim 11
Dependent Claim
86 words
Apparatus for determining heart output comprising X-ray source means for providing at least one pulsed source of X-rays impinging on said heart, detection means for receiving said X-rays from said heart, processor means for creating digital or analog signals related to heart contractions at different times, and said processor means having means for substracting and summing said signals to effect separation of heart displacement signals from heart contraction signals, and conversion means for changing said heart contraction signals into information which relates to determining heart output.
Claim 12
Dependent Claim
25 words
The apparatus of claim 9 including said processor means having means for converting said heart contraction signals into volume of blood pumped by said heart.
Claim 13
Dependent Claim
22 words
The apparatus of claim 10 including display means cooperating with said processor means for displaying information related to said heart contraction signals.
Claim 14
Dependent Claim
120 words
Apparatus of claim 11 wherein said processor means including means for determining the reduction in volume of the heart by the relationship ##EQU6## wherein dV t =the reduction in heart volume during the time t and t-1; t=the time instant of the image I n ; t-1=the time instant of the image I n-1 ; F=a calibration factor that relates pixel size to heart size in the image; π=3.14; A k and B k =the axes of A and B of the ellipses at the level k coinciding with the projection planes; C=the length of the ventricle; dA, dB and dC each represent the difference in axes A, B and C, respectively, during the time interval between t-1 and t.
Claim 15
Dependent Claim
23 words
The apparatus of claim 9 including pulse means for pulsing said X-rays at a rate a about 15 to 60 pulses per second.
Claim 16
Dependent Claim
122 words
Apparatus for measuring ventricular load impedance in real time comprising X-ray source means for providing at least one pulsed source of X-rays impinging on said heart, detection means for receiving said X-rays from said heart, processor means for creating digital or analog signals related to heart contractions at different times, said processor means having means for substracting and summing said signals to effect separation of heart displacement signals from heart contraction signals, said processor means having means for converting said heart contraction signals into volume of blood pumped by said heart, and pressure measuring means for providing a reading of blood pressure in the heart chamber, and means for providing the ratio of volume signal to pressure signal thereby defining load impedance.
Claim 17
Dependent Claim
122 words
Apparatus for measuring ventricular load impedance in real time comprising X-ray source means for providing at least one pulsed source of X-rays impinging on said heart, detection means for receiving said X-rays from said heart, processor means for creating digital or analog signals related to heart contractions at different times, said processor means having means for substracting and summing said signals to effect separation of heart displacement signals from heart contraction signals, said processor means having means for converting said heart contraction signals into volume of blood pumped by said heart, and pressure measuring means for providing a reading of blood pressure in the heart chamber, and means for providing the ratio of volume signal to pressure signal thereby defining load impedance.
Claim 18
Independent Claim
119 words
A method of measuring ventricular load impedance in real time comprising pulsing X-ray beams through a heart chamber containing a contrast medium and blood, detecting the portion of said X-rays not absorbed by said heart and chest, converting said detected X-rays into electrical signals, effecting subtraction of said signals detected at one time from those of another time, and summing the resulting pixel values, whereby said signals relating to heart displacement will be cancelled and said signals relating to heart contraction will remain, converting heart contraction signals into a corresponding volume of blood pumped by said heart in a predetermined time interval, determining ventricular pressure, and dividing said ventricular pressure by said volume of blood pumped by said heart.
Claim 19
Independent Claim
119 words
A method of measuring ventricular load impedance in real time comprising pulsing X-ray beams through a heart chamber containing a contrast medium and blood, detecting the portion of said X-rays not absorbed by said heart and chest, converting said detected X-rays into electrical signals, effecting subtraction of said signals detected at one time from those of another time, and summing the resulting pixel values, whereby said signals relating to heart displacement will be cancelled and said signals relating to heart contraction will remain, converting heart contraction signals into a corresponding volume of blood pumped by said heart in a predetermined time interval, determining ventricular pressure, and dividing said ventricular pressure by said volume of blood pumped by said heart.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-01-04 | 1991-07-06 | 1992-01-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-01-04 | 1995-07-06 | 1996-01-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-01-04 | 1999-07-06 | 2000-01-05 | $7700.00 | Window Closed / Lapsed |