U.S. patent number 3,754,555 [Application Number 05/186,654] was granted by the patent office on 1973-08-28 for controllable barbed intracardial electrode.
Invention is credited to German Schmitt.
United States Patent |
3,754,555 |
Schmitt |
August 28, 1973 |
**Please see images for:
( Certificate of Correction ) ** |
CONTROLLABLE BARBED INTRACARDIAL ELECTRODE
Abstract
A repeatably implantable intracardial electrode for use with a
heart stimulation device provides a piston movable axially within a
cavity in the electrode body. The piston carries resilient prongs
which move through channels in the electrode body to engage the
heart tissue for implantation of the electrode. The prongs are
retracted when tension is exerted on the piston, and are advanced
by force on the piston.
Inventors: |
Schmitt; German (44 Munster,
DT) |
Family
ID: |
22685787 |
Appl.
No.: |
05/186,654 |
Filed: |
October 5, 1971 |
Current U.S.
Class: |
607/128 |
Current CPC
Class: |
A61N
1/0573 (20130101) |
Current International
Class: |
A61N
1/375 (20060101); A61N 1/05 (20060101); A61N
1/372 (20060101); A61n 001/04 () |
Field of
Search: |
;128/2A,2R,2.5D,2.5F,2.5R,2.6E,2.1E,404,418,419P,419R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Kamm; William E.
Claims
What is claimed is:
1. A controllable repeatably implantable electrode comprising
a conducting head,
a conductor electrically connected to said head,
said head having a front portion and elongated body portion
defining an axially oriented cavity,
a tubular insulating member connected to said body portion and
aligned with said cavity, said conductor being carried away from
said head within said insulating member,
a plurality of channels extending from said cavity through said
front portion to the exterior of said head, and each disposed at an
angle to the axis of said cavity,
a rigid cylindrical piston movable axially within said cavity
between a forward implantation position and a retracted position,
carrying a plurality of resilient prongs each extending into a said
channel,
a removable force-transmitting member carried within said
insulating member, having one end bearing against said piston and
the other end remote from said piston,
a flexible tension-transmitting member carried within said
insulating member, having one end attached to said piston and the
other end remote from said piston,
said piston being moved within said cavity to said forward
implantation position by force applied to said remote end of said
force-transmitting member, said prongs being thereby moved through
said channels to engage the heart tissue for implantation of said
electrode, and said piston being moved to said retracted position
by tension exerted on said remote end of said tension-transmitting
member, said prongs being thereby retracted and freed from said
heart tissue for removal of said electrode.
2. An intracardial electrode for use in artificial stimulation of a
patient's heart, suitable for prolonged implantation within a
patient's body,
said electrode comprising
an elongated body defining an axially oriented cavity,
a tubular flexible insulating member connected to said body and
aligned with said cavity,
a flexible electrical conductor connected to said body and carried
away therefrom within said flexible insulating member,
said body having at least one channel extending from said cavity to
the exterior of said body and disposed at an angle to the axis of
said cavity, a rigid piston movable axially within said cavity, and
at least one resilient prong longer than a said channel, attached
to said piston and extending into a said channel,
a substantially rigid force-transmitting member carried within said
insulating member, having one end bearing against said piston and
the other end remote from said piston and protruding from said
insulating member, and
a generally flexible retracting member attached to said piston and
carried away therefrom within said conducting member,
whereby force exerted on said remote end of said force-transmitting
member is transmitted by said bearing end to said piston, causing
said prong to extend through said channel to engage the tissue of
the said patient's heart, and tension exerted on said retracting
member is transmitted to said piston and retracts it, freeing said
prongs from the heart tissue.
Description
This invention relates to an intracardial electrode for use with
heart stimulation devices. In particular, it relates to an
implantable electrode having an insulated helical conductor, and
provided with a metallic head, which can be placed against the
inner surface of the wall of the heart.
An electrode of this sort is introduced into the heart through a
vein; generally a jugular vein is used, particularly the jugularis
externa. To accomplish this, the jugular is opened, and the
electrode is then pushed through the vein, metal head foremost,
until it reaches the auricle of the heart.
Depending on the clinical situation of the patient, stimulation of
either the auricle or the ventricle may be desired. In the case of
stimulation of the auricle, the head of the electrode is pressed
against the auricle wall; 24 the case of stimulation of the
ventricle, the electrode is fed through the heart valve and is
pressed against the wall of the ventricle. It is desirable to
dispose the helical conductor in a bowed position, so that the head
is pressed against the wall of the heart by the resilience of the
conductor.
After the electrode has reached the desired position, measuring and
testing apparatus is connected to the end of the conductor that
remains outside the patient's body, in order to measure the
stimulation threshold of the heart.
After these measurements have been completed, the conductor is
connected to a cardiac stimulation device (heart pacer), which may
be either external to the body or implanted within the patient.
When the heart pacer is to be implanted, a support or bed for the
stimulator is provided in the thorax or abdomen and then connected
to the neck by means of tubing that is led through the body. The
external end of the helical conductor (remote from the heart) is
then led through the tubing to the stimulator support, after which
the tube is removed from the body and the conductor is connected to
the stimulator.
An electrode that may be attached to the surface of the wall of the
heart, rather than within the wall tissue, provides a most
important advantage, in that the surgical procedure for
implantation is much less extensive. However, such an exterior
electrode has previously involved the disadvantage that after a
period of use the electrode sometimes becomes dislodged, separating
the operative tip of the electrode from the heart wall. Such
dislocation is generally the result of movements of the heart wall.
As a result, the patient must undergo a further surgical operation
in order to replant the electrode, with obvious undesirable stress
on the patient.
To prevent such dislocation, it has been attempted to place the tip
of the electrode between trabecular muscles; but such muscles are
not common in the heart wall. It has also been suggested that a
portion of the head of the electrode might be formed as a truncated
cone, so that the head can operate as a barb. At present, no useful
measurements can be expected using such a device.
It is therefore an object of the invention to provide an improved
implantable intracardial electrode, which substantially reduces the
likelihood of dislocation of the electrode, and thus increases the
safety of the patient using it.
It is also an object to provide an electrode whose position within
the heart can be altered by an external control, without the need
of additional surgical procedures.
It is a further object to provide such an electrode that is
detachable and reimplantable without injury to the patient.
According to the invention, the electrode provides a cavity in
which is placed a piston movable coaxial with and connected to the
conductor. A number of resilient prongs or barbs are attached to
the cylinder. Channels are provided in the tip of the head, at an
angle to the cavity axis, and the resilient prongs are extendable
through these channels to the outside of the electrode.
Motion of the cylinder towards the heart wall pushes these
resilient prongs into the myocardium, securing the electrode in
place. To obtain this effect, it is important that the prongs be
placed at a suitable angle with respect to the axis of the piston,
and that the diameter of the prongs be suitably chosen. Good
results may be obtained when the channels in the head of the
electrode are placed at an angle of about 40.degree. with respect
to the axis of the piston.
The prongs in a preferred embodiment may be advantageously made of
nylon of 0.3 mm diameter. Alternatively, one may use metal prongs
covered with insulating material. The use of metal prongs has the
advantage that the placement of the prongs in the wall of the heart
may be observed with the aid of X-rays.
If on the first attempt the electrode is not satisfactorily
implanted, the prongs may be freed from the heart wall tissue by
means of a thin flexible wire attached to the piston, and led
through the inside of the insulating member. Tension on the wire
retracts the piston and thereby the prongs.
Forward motion of the piston, to force the prongs into the
myocardium, is accomplished by means of a stiff wire, also led
through the inside of the insulating member. To obtain good
operating contact of this wire with the piston, the end of the
piston nearest the conductor may be covered with a metallic
cap.
Other objects, features and advantages will appear from the
following description of a preferred embodiment of the invention,
taken together with the attached drawing thereof, in which:
FIG. 1 is a cross-sectional view of the electrode.
Referring to the drawing, electrode 10 is connected to a helical
conductor 12, carried within an insulating member 14, such as a
tube of silicone rubber. Conductor 12 may be externally connected
at its remote end to a heart stimulation device. Conductor 12 is
electrically connected with a head 16, which may be made, for
example, of platinum; a narrowed portion 18 of head 16 is inserted
into insulating member 14, so that portion 18 lies between
conductor 12 and insulating member 14. In the construction of head
16, the end of conductor 12 is pressed into the material of head
portion 18, ensuring good electrical contact.
Head 16 contains a cavity 20, within which a hollow cylindrical
piston 22 is axially movable. A number (for example four) of
resilient prongs 24 are attached to piston 22; such prongs may for
example be made of nylon or insulated stainless steel. Each prong
24 extends into a channel 26 through head 16, each channel being
disposed at an angle of about 40.degree. with respect to the piston
axis. Four prongs are a desirable number.
Prongs 24 are firmly attached at 28, as by welding, to the end of
piston 22 nearest conductor 12. At the forward end of the piston
the prongs are retained by a ring 30, to prevent their
spreading.
A force-transmitting member is provided in the form of a stiff wire
32, carried within insulating member 14, by which piston 22 can be
moved forward, causing prongs 24 to protrude through channels 26 to
the exterior of electrode 10, enabling them to engage the tissue of
the myocardium.
In addition, a thin wire 34 may be attached to cylinder 22, for
instance by welding, to provide a tension-transmitting member by
means of which piston 22 together with attached prongs 24 can be
retracted if the first attempt at implantation in the myocardium is
unsatisfactory.
Prongs 24 may be of varying length, depending on whether the
electrode is to be attached to the auricle or the ventricle. The
length should be such that when piston 22 is in its extreme forward
position (shown in the drawing), a length of about 3 mm protrudes
from head 16, if the head is to be attached to the auricle, or a
length of 4 to 5 mm if it is to be attached to the ventricle.
The outer diameter of insulating member 14 may be about 2.5 mm,
while the helix of the conductor may have an outside diameter of 1
mm and an inside diameter of 0.7 mm. In constructing the electrode,
a lubricant, such as one made of silicone, may be provided,
ensuring free motion of the prongs through the channels. After
inserting the lubricant, piston 22 is moved back and forth several
times, after which the superfluous lubricant may be removed.
In use, the electrode is secured in place by pushing on stiff wire
32 to force prongs 24 outwardly into the heart wall tissue. Wire 32
may then be removed through insulating member 14, leaving only the
coiled conductor 12 and thin wire 34, which are relatively
flexible. The end of insulating member 14 remote from electrode 10,
with conductor 12, may then be connected to a suitable heart
stimulation device internal or external to the patient. In the
event that electrode 10 is unsatisfactorily placed or must be
removed, prongs 24 are retracted by tension on thin wire 34, and
stiff wire 32 may be reinserted through the remote end of
insulating member 14 to exert the desired force on cylinder 22 to
cause reimplantation.
* * * * *