Method and apparatus for monitoring an organ of a patient
An apparatus for determining tissue versus fluid components of an organ include a detector that generates a detector signal based on electrical signals derived from tissue and fluid. The apparatus includes a signal processor in communication with the detector which subtracts in real time a tissue component from the detector signal and produces a fluid volume signal. A method for monitoring a patient's fluid volume of a patient's organ. An apparatus for monitoring a patient's organ. A method for monitoring a patient's organ. A method to piggyback an admittance system onto a AICD/Bi-ventricular Pacemaker for a heart of a patient, in particular a weakened heart having features consistent with congestive heart failure. An apparatus for monitoring an organ, such as a heart, lungs, brain, skeletal muscle, and bladder of a patient which includes a detector which detects the admittance of the organ. The apparatus includes a transmitter in communication with the detector which transmits a wireless signal indicative of the admittance of the organ. A method for monitoring an organ of a patient includes the steps of detecting with a detector the admittance of the organ. There is the step of transmitting with a transmitter in communication with the detector a wireless signal indicative of admittance of the organ.
1. An implanted device for a heart of a patient comprising:
a housing;
a first electrode and a second electrode configured to be disposed in the right ventricular septum (RV) of the heart;
a lead having a third and fourth electrode that is configured to extend from the housing into the coronary sinus extending onto the lateral epicardial coronary vein of the heart;
a drive circuit disposed in the housing to cause the electrodes to generate emitted electrical signals;
a transmitter disposed in the housing that transmit received signals from the electrodes after the emitted signals have passed through the heart;
a detector that generates a detector signal based on electrical signals derived from tissue and fluid in the heart; and
a signal processor in communication with the detector which subtracts in real time a tissue component from the detector signal and produces a fluid volume signal to determine stroke volume of the heart using admittance as a function of electricity path through the tissue.
2. The implanted device as described in claim 1 wherein the electrodes produce a combined signal that has a tissue component and a fluid component.
3. The implanted device as described in claim 2 wherein the electrodes have a varying distance between them and the processor determines heart admittance based on the varying distance between the electrodes.
4. The implanted device of claim 3 wherein the drive circuit causes the electrodes to generate emitted electrical signals at only a single frequency of about 20 kHz.
5. The implanted device as described in claim 4 wherein the fluid is blood, the tissue is myocardium and the processor determines LV, RV, LA, or RA length, area, and/or volume of the heart in 1, 2 or 3 dimensions.
6. The implanted device as described in claim 5 wherein the myocardial component Rm is determined by
R
m
=
-
Im
{
Z
_
}
×
(
1
+
(
ωɛ
m
σ
m
)
2
)
ωɛ
m
σ
m
,
where Z is the complex impedance; ω=2πf where is the frequency; ∈ m is permittivity of muscle; and σ m is the conductivity of muscle.
7. The implanted device as described in claim 6 wherein the fluid is blood and blood component Rb is determined by
R
b
=
Re
{
Z
_
}
-
R
m
1
+
(
ω
R
m
C
m
)
2
,
where Z is the complex impedance; ω=2πf where f is the frequency; R m is the resistance of muscle, and C m is the capacitance of muscle.
8. The implanted device as described in claim 7 wherein the signal processor subtracts in real time the myocardial component from the detector signal and produces the left and right ventricle, and left and right atrial blood volume signal.
9. An implanted device for a heart of a patient comprising:
a housing;
a first electrode and a second electrode configured to be disposed in the right ventricular septum (RV) of the heart;
a lead having a third and fourth electrode that is configured to extend from the housing into the coronary sinus extending onto the lateral epicardial coronary vein of the heart, the first, second, third and fourth electrodes produce a combined signal that has a tissue component and a fluid component;
a drive circuit disposed in the housing to cause the electrodes to generate emitted electrical signals;
a transmitter disposed in the housing that transmit received signals from the electrodes after the emitted signals have passed through the heart;
a detector that generates a detector signal based on electrical signals derived from tissue and fluid in the heart; and
a signal processor in communication with the detector which subtracts in real time a tissue component from the detector signal and produces a fluid volume signal to determine stroke volume of the heart using admittance, the electrodes have a varying distance between them and the processor determines heart surface admittance based on the varying distance between the electrodes, the fluid is blood, the tissue is myocardium and the processor determines LV, RV, LA, or RA length, area, and/or volume of the heart in 1, 2 or 3 dimensions, the myocardial component Rm is determined by
R
m
=
-
Im
{
Z
_
}
×
(
1
+
(
ωɛ
m
σ
m
)
2
)
ωɛ
m
σ
m
,
where Z is the complex impedance; ω=2πf where f is the frequency; ∈ m is permittivity of muscle; and σ m is the conductivity of muscle.