U.S. patent number 3,693,625 [Application Number 05/033,745] was granted by the patent office on 1972-09-26 for heart stimulator and heart-powered energy supply therefor.
This patent grant is currently assigned to U.S. Philips Corporation. Invention is credited to Michel Joseph Auphan.
United States Patent |
3,693,625 |
Auphan |
September 26, 1972 |
HEART STIMULATOR AND HEART-POWERED ENERGY SUPPLY THEREFOR
Abstract
A device for supplying electrical energy to a heart stimulator
which is formed as an air-tight casing arranged to be placed within
the human body in close proximity to the heart muscle. The casing
has housed therein an annularly arranged magnetic circuit with a
rotor arranged in a gap of the circuit. A rotary piston is
accommodated within a piston chamber having four compartments
divided in pairs. One of the pair is connected via a flexible tube
to a first flexible bag arranged at the tip of the heart and the
other pair communicates via another flexible hose to a second
flexible elastic bag. The elastic bags contain fluid which
communicate alternately between the pairs of compartments within
the chamber so that upon the pumping action of the heart the piston
is caused to oscillate in a rotary motion and mechanical coupling
means are connected between the piston and a driving member mounted
coaxially with the rotor so as to drive the rotor thereby producing
electrical signals in response to the movement of the heart.
Inventors: |
Auphan; Michel Joseph
(Courbevoie, FR) |
Assignee: |
U.S. Philips Corporation (New
York, NY)
|
Family
ID: |
9033996 |
Appl.
No.: |
05/033,745 |
Filed: |
May 1, 1970 |
Foreign Application Priority Data
|
|
|
|
|
May 13, 1969 [FR] |
|
|
6915527 |
|
Current U.S.
Class: |
607/19;
607/35 |
Current CPC
Class: |
A61N
1/378 (20130101); A61N 1/3785 (20130101) |
Current International
Class: |
A61N
1/378 (20060101); A61N 1/372 (20060101); A61n
001/36 () |
Field of
Search: |
;128/1R,419P,419R
;310/37 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kamm; William E.
Claims
What is claimed is:
1. A device for supplying energy for an intracorporal heart
stimulator, comprising an airtight casing to be placed within the
human body, an annularly arranged magnetic circuit housed within
said casing, a winding coupled to said magnetic circuit to produce
electrical energy said circuit having a gap therein, a rotor
arranged in said gap for oscillatory movement, a multicompartment
piston chamber arranged within said magnetic circuit, a piston
mounted for rotatable movement within said chamber about an axis of
rotation parallel and eccentric to the axis of rotation of said
rotor, hydraulic means connected with said chamber for transmitting
pulses thereto in response to movements of the heart so as to cause
rotational displacement of said piston in accordance therewith, , a
driving member rotatably mounted coaxially with said rotor and
having means contacting said rotor for driving same, and mechanical
coupling means for causing movement of said driving member in
response to rotational movement of said piston so that when said
piston is rotatably driven as a result of heart movement said
driving member will be caused to rotate and cause oscillatory
movement of said rotor so as to produce electrical energy.
2. The device according to claim 1 wherein said piston chamber
comprises first, second, third and fourth compartments, the volume
of said first and third compartments being variable and equal to
each other, the volume of said second and fourth compartments being
variable and equal to each other and wherein said hydraulic means
comprises a first flexible bag arranged on the tip of the heart, a
first flexible liquid circulation tube connected to said first
flexible bag and communicating with said first and third
compartments, a second elastic bag of expansion and a second
flexible liquid circulation tube connected to said second elastic
bag of expansion and communicating with said second and fourth
compartments.
3. The device according to claim 1 further comprising at least one
magnet disposed near said rotor for producing a magnetic field
perpendicular to said rotor.
4. The device according to claim 1 wherein said piston is mounted
for rotation about an axis of the casing which is filled with air,
and wherein said piston is made of magnetic material and further
comprising a pair of magnets arranged symmetrically outside of said
piston chamber so as to form a magnetic coupling thereby producing
a drive for the piston.
5. The device according to claim 1 further comprising a capacitor
connected to said winding and forming an oscillatory circuit for
the transmission of the mechanical energy of the rotor.
6. The device according to claim 1 wherein said mechanical coupling
means for causing movement of said driving member in response to
rotational movement of said piston comprises a first gear wheel
arranged on said driving member and a second gear wheel associated
with said piston and arranged in mesh with said first gear
wheel.
7. The device according to claim 1 further comprising a heart
stimulator carried within said casing, an energy accumulator
connected to said stimulator and a switch for connecting said
oscillatory circuit to said energy accumulator, one of the
electrodes of said stimulator being formed by said casing and the
other electrode being fixed to said flexible bag at the tip of the
heart.
Description
This invention relates to a supply device for an intracorporal
heart stimulator in the domain of medical prostheses.
Cardiac stimulators used for some diseases provide electric pulses
to the myocardium by electrodes, different sources of energy are
available for feeding these stimulators.
It is now common practice to use a battery within the body, but
this involves two disadvantages: on the one hand the longevity of a
battery is limited and on the other hand rupture of the flexible
wires connecting the battery to the stimulator may occur due to
shaking by the heart beat.
Research made on the sources of energy suitable for such uses tends
to obviate these disadvantages by developing an autonomic source of
energy, which will be substantially independent of time.
In this respect research has been made for developing batteries
having electrodes consumable by biological liquids. However, the
longevity of these electrodes and any toxic effects they may have
on the organism cannot be guaranteed.
Also, the use of thermal sources taking their energy from nuclear
reaction involves many problems relating to either the dangers of
the circulation of a radioactive material or the heat exchange at
high temperatures also the cost of an apparatus based on this
principle would be prohibitive
The use of the mechanical energy of the heart proposed in various
methods should lead to an interesting solution. In fact, since the
heart gives off about 15 W in contracting it must be capable of
supplying the few hundred microwatts required for feeding a
stimulator.
However, the mecano-electric transformation tests on piezo-electric
materials have not produced the desired results. Since the charges
accumulated at each mechanical deformation of the piezo-electric
bodies are low, these deformations have to be accumulated to the
highest possible frequency for obtaining a sufficient total
energy.
A different solution has been described by the Applicant in French
Pat. No. 1,460,772 and the Patent of Addition Nr. 92 782. The
apparatus proposed forms not only an electric current generator but
also a pulse generator for stimulating the heart. It comprises in
an air-tight box a magnetic circuit, in the gap of which a rotor is
adapted to oscillate between two pivots. An oscillation of the box
produded by the movement of the heart causes the rotor to pass from
an unstable position to a stable position and during this movement
a sequence of rapid oscillations of the rotor induces in the
magnetic circuit an oscillatory current of decreasing amplitude.
For transmitting the movement of the heart the box comprises a
pendulum associated with a rotatable piece coaxial to said rotor
and provided with a contact finger which co-operates with a pin of
said rotor. This system, however, can only provide pulses at a
predetermined frequency usually of about 1 Hz. For many cases it
is, however, desirable to have available a system of variable
frequency so that the heart may obtain pulses at different
rhythms.
The present invention based on the same principle of
mecano-electric transformation provides a supply device for an
intracorporal heart stimulator, which may be of the conventional
type.
The supply device is formed by a member converting mechanical
energy into electric energy and comprises an oscillatory rotor
arranged in the gap of a magnetic circuit and means for
transmitting the movement of the heart to said rotor, which means
comprise a rotatable piece coaxial to said rotor and provided with
at least one mechanical contact member for driving said rotor.
According to the invention said means further comprises a rotatable
piston mechanically coupled with the rotatable piece and a member
controlling the displacements of said piston in accordance with the
movements of the heart .
Various characteristics of the invention will be apparent from the
following description given by way of example with reference to the
accompanying drawings, which show
in FIG. 1 an elevation of the open casing comprising the supply
device in accordance with the invention;
in FIG. 2 a schematic view of the rotatable piston shown at the
center of FIG. 1;
in FIG. 3 an over-all view of the casing and the transmission of
the movements of the heart; and in FIG. 4 a schematic diagram
showing the stimulator.
An airtight casing 1 accommodates an annular magnetic circuit 2a
associated with a winding 2b, the gap accommodating a rotor 3. Two
auxiliary magnets 4 of the kind described in the aforesaid Patent
Specification produce a magnetic field at right angles to the axis
of the rotor and hence a return-couple for the latter.
The rotor is provided with a driving pin 5 co-operating with a
finger 6 of a rotatable piece 7 which is coaxial to the rotor, the
pin 5 and the finger 6 forming the mechanical contact elements for
driving said rotor. The rotatable piece is provided with a gear
wheel 8 in mesh with the gear wheel 9 associated with a rotatable
piston 11, mounted along the axis AA' of the casing 1 inside the
annular magnetic circuit. The space 12 accommodating the piston 11
is divided into four chambers 13a, 13b, 14a and 14b of pairwise
equal, variable volumes. These chambers (see FIGS. 2 and 3) are
connected, as far as the first two are concerned by the flexible
tube 15 with a plastic bag 18 arranged on the tip of the heart 17,
the two others, by the flexible tube 16 with an elastic bag 19 of
expansion.
Initially the bag 18 is filled with a liquid. At each systole the
bag 18 is compressed between the tip of the heart and the
surrounding tissues; the liquid is thus expelled into the flexible
tube 15, it traverses the space 12 and emanates from the tube 16
towards the bag 19. After the systole the tension of the second
elastic bag pushes the liquid back to the first bag, which is no
longer subjected to the pressure of the tip of the heart.
During each reciprocatory flow of the liquid, the rotatable piston
11 is caused to perform an alternating movement which is
transmitted by the gear wheels and produces the oscillation of the
rotor under the action of the couple produced by the magnets 4.
The winding 2b of the magnetic circuit 2a is connected to the
terminals of a first capacitor, so that an oscillatory circuit is
formed. If the frequency of the latter lies near the oscillation
frequency of the rotor, an automatic transmission of energy is
obtained from the rotor to the oscillatory circuit.
Each time when the energy reaches its maximum level, it is
transmitted, for example, by an electric switch 24, to a second
capacitor 25 for feeding a stimulator 26 of conventional type.
The switch 24, the capacitor 25 and the stimulator 26 may be
accommodated inside the casing 1 near the rotatable piston for
instance. (not shown for the sake of clarity).
The pulses generated by the stimulator 26 are transmitted via leads
27 and 28 to electrodes schematically indicated by arrows 29 and
30, one of these electrodes may be formed by the casing 1, whereas
the other (30, see FIG. 3) may be fixed to the flexible bag 18,
when the liquid is conductive.
In order to ensure a perfect seal between the space 12 and the
assembly of the device the driving system is formed by a magnetic
coupling so that a shaft traversing the casing is not required.
For this purpose the piston 11 is made of magnetic material and
associated with two external, symmetrical magnets.
The invention may be used in the treatment of given cardial
diseases by prostheses.
* * * * *