US2015119947A1PendingUtilityA1
Method and Apparatus for Determining Cardiac Performance in a Patient
Est. expirySep 9, 2023(expired)· nominal 20-yr term from priority
A61N 1/36842A61N 1/39622A61N 1/36843A61N 1/3627A61B 5/0215A61N 1/36585A61B 5/053A61N 1/3968A61N 1/36514A61B 5/413A61N 1/368A61N 1/3702A61N 1/3962
45
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
An apparatus for determining heart transplant rejection of a heart in a patient includes at least two electrodes adapted to be sewn into the heart that span the left ventricle. The apparatus includes a voltage generator adapted to be inserted in the patient which generates a voltage to the two electrodes and senses the resulting voltage from the two electrodes. A method for determining heart transplant rejection of a heart in a patient. A pacemaker for a patient (including bi-ventricular pacing and AICDs). The pacemaker includes an RV lead having four electrodes adapted to be inserted into the RV apex. The pacemaker includes a voltage generator which generates a voltage signal to the electrodes and senses the instantaneous voltage along the length of the RV and determines the real and imaginary components to remove the myocardial components of the septum and RV free wall to determine absolute RV blood volume. The pacemaker includes a battery connected to the voltage generator. The pacemaker includes a defibrillator connected to the battery. The pacemaker can also be a bi-ventricular pacemaker to restore RV and LV synchrony during contraction. A method for assisting a heart of a patient.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . An implantable pacemaker for a patient comprising:
a right ventricular (RV) lead having a plurality of electrodes spanning a length of the RV adapted to be inserted into an RV apex; a voltage generator configured to generate a voltage signal to the electrodes and sense an instantaneous voltage in the RV and determine real and imaginary components to remove a myocardial component of a septum and RV free wall to determine absolute RV blood volume; a battery connected to the voltage generator; a defibrillator connected to the battery; and a bi-ventricular pacemaker configured to resynchronize RV and left ventricle (LV) ventricular contraction based on the absolute blood volume to avoid heart failure.
2 . The pacemaker as described in claim 1 including a voltage regulator having a processor.
3 . The pacemaker as described in claim 2 including a pressure sensor configured for measuring instantaneous pressure of a heart chamber in communication with the processor.
4 . The pacemaker as described in claim 3 wherein the processor is configured to produce a single waveform at a desired frequency for the RV lead.
5 . The pacemaker as described in claim 3 wherein the processor is configured to produce a plurality of desired waveforms at single or multiple desired frequencies for the RV lead.
6 . The pacemaker as described in claim 5 wherein the processor is configured to produce the plurality of desired waveforms at single or multiple desired frequencies simultaneously, and the processor is configured to separate the plurality of desired wave forms at desired frequencies the processor receives from the RV lead.
7 . The pacemaker as described in claim 6 wherein the plurality of electrodes are configured to measure a least one segmental volume of a heart chamber.
8 . The pacemaker as described in claim 7 wherein the absolute RV blood volume is determined according to a non-linear relationship is
β( G )(σ=0.928 S/m )=1+1.774(10 7.481×10 −4 (G−2057) )
where: G is the measured conductance (S), the calculations have been corrected to the conductivity of whole blood at body temperature (0.928 S/m), and 2057 is the asymptotic conductance in μS when a cuvette is filled with a large volume of whole blood.
9 . The pacemaker as described in claim 8 wherein blood volume with respect to time as measured by the electrodes of the RV lead is determined according to
Vol
(
t
)
=
[
β
(
G
)
]
[
L
2
σ
b
]
[
Y
(
t
)
-
Y
p
]
where: β(G)=the field geometry calibration function (dimensionless), Y(t)=the measured combined admittance, σ b is blood conductivity, L is distance between measuring electrodes, and Y p =the parallel leakage admittance, dominated by cardiac muscle.
10 . The pacemaker as described in claim 9 wherein the pressure sensor is in contact with the RV lead to measure ventricular pressure in the RV.
11 . The pacemaker as described in claim 10 wherein the plurality of electrodes includes intermediate electrodes configured to measure an instantaneous voltage signal from the heart, and outer electrodes to which a current is applied from the processor.
12 . The pacemaker as described in claim 11 wherein the pressure sensor is disposed between the intermediate electrodes and the outer electrodes.
13 . The pacemaker as described in claim 12 wherein the computer is configured to convert conductance into a volume.
14 . The pacemaker as described in claim 7 wherein blood volume with respect to time as measured by the electrodes of the RV lead is determined according to
Vol( t )=ρ L 2 g b ( t )exp[γ·( g b ( t )) 2 ]
where Vol(t) is the instantaneous volume, ρ is the blood resistivity, L is the distance between the sensing electrodes, g b (t) is the instantaneous blood conductance, and γ is an empirical calibration factor.
15 . A method for assisting a heart of a patient comprising the steps of:
inserting into a right ventricle (RV) apex an RV lead of a pacemaker having a plurality of electrodes that span a length of the RV; generating a voltage signal to the electrodes from a voltage generator; and sensing an instantaneous voltage in the RV with the voltage generator to determine real and imaginary components of the voltage to remove a myocardial component of the septum and RV free wall to determine absolute RV blood volume based on the absolute blood volume to avoid heart failure.
16 . A method as described in claim 15 including the step of producing a plurality of desired wave forms at desired frequencies for the RV lead.
17 . A method as described in claim 16 wherein the producing step includes the step of producing the plurality of desired waveforms at desired frequencies simultaneously, and including the step of a processor separating the plurality of desired waveforms at desired frequencies the processor received from the RV lead.
18 . A method as described in claim 17 wherein the sensing step includes the step of the voltage generator applying a non-linear relationship according to
β( G )(σ=0.928 S/m )=1+1.774(10 7.481×10 −4 (G−2057) )
where: G is the measured conductance (S), the calculations have been corrected to the conductivity of whole blood at body temperature (0.928 S/m), and 2057 is the asymptotic conductance in μS when a cuvette is filled with a large volume of whole blood.
19 . A method as described in claim 18 wherein the sensing step includes the step of determining instantaneous volume according to
Vol
(
t
)
=
[
β
(
G
)
]
[
L
2
σ
b
]
[
Y
(
t
)
-
Y
p
]
where: β(G)=the field geometry calibration function (dimensionless), Y(t)=the measured combined admittance, and Y p =the parallel leakage admittance, dominated by cardiac muscle.
20 . The method of claim 19 including the step of treating the patient if the RV volume is increasing.Cited by (0)
No later patents cite this yet.
References (0)
No backward citations on record.