Note: Descriptions are shown in the official language in which they were submitted.
26
BACKGROUND OF THE INVENTION
The Electrocardiogram (ECG) has proven over the years to
be the single most effective clinical record for the diagnosis
of cardiac muscle and cardiac nervous conduction abnormalities.
An electrocardiogram is routinely taken not only on patients
suspected of having cardiac disease, '~ut also on normal patients
to establish base line cardiac data. Thus, millions of ~CG
tracings are recorded yearly in private physicians' offices
and in hospitals. It is imperative that these tracings be
reliable and also that they be obtained rapidly to minimize
the cost.
Generally, the ECG is usually comprised of twelve distinct
records (i.e., tracings) which are obtained from a combination
of specific electrical signals obtained from the body of the
patient. These signals result from the heart's electrical
activity which is conducted throughout the body. The signals,
ordinarily in the millivolt range, may be sensed by metal
electrodes making electrical contact with the body by way of
electrically conductive electrode paste. The signals are
transmitted from the electrodes through cables to an electro-
cardiograph or ECG recorder which includes amplifying circuity,
a heat stylus writing mechanism and switching circuitry. The
latter circuitry permits combining the signals ordinarily taken
from ten different positions on a patient's body to obtain
the twelve tracings ordinarily desired.
The twelve tracings, ordinarily adequate to obtain the
heart's full spectrum of electrical data, are obtained from
electrodes placed on the patient's four extremities and six
electrodes carefully positioned on the precordium (i.e. the
chest wall of the heart area). The latter six electrodes in
the precordial positions are designated as Vl, V2, V3, V4,
V5 and V6. In certain cases, other positions on the chest may
%~
be chosen (e.g. V3R) so that the specific example using
positio~s Vlto V6 is illustrative rather than limiting.
The usual practice is to apply the electrodes to the
arms (LA, RA), legs (LL, RL) and procordium (Vl, V2, V3,
V4, V5and V6), with the electrodes being of a clamp type,
suction cup type or adhesive type~ Such electrodes must be
applied one-at-a-time and, in the case of the precordial
electrodes particularly, require careful placing at specific
anatomical locations. Thus, the careful and time-consuming
attention of a skilled nurse, technician or doctor is required.
In a preferred embodiment of the present invention, a
chest piece includes a strip of stretchable material, with
apertures therein for receiving electrodes. When inserted in
the apertures, the spacing between the electrodes and the
pattern thereof correspond to the relative proportional spacing
of precordial anatomic positions preferred for electrocardio-
graph monitoring.
Advantageously, each electrode may be provided with
flange portions for releasably mating with the edges of the
apertures, whereby the strip or some or all of the electrodes
may be replaced without replacement of the entire chest piece.
Each electrode may include a cup shaped member for
containing electrolyte to be placed against the chest of the
patient. Advantageously, the electrolyte may be introduced
into the cup shaped member through the electrode. Alternative-
ly, the electrolyte may be in the form of an electrically
conductive gel pad.
The electrocardiograph electrode assembly may also
inclu'de a retainer or holder means for engaging the ends of
the stretchable strip and for stretching the strip a select-
able amount to position and maintain the electrodes in contact
with precordial anatomic positions on the chest of the patient.
Advantageously, the holder may be releasably attached to the
chest piece, and may take the form of a member positioned
behind the back of the patient or weights positioned along the
sides of the chest of the patient.
It is accordingly an object of the present invention to
provide novel and improved method and apparatus for rapidly
applying electrocardiograph electrodes to a patient's body in
clinically acceptable anatomic regions despite a wide range of
chest sizes a~d configurations.
THE DRAWINGS
Figure 1 is a plan view of one embodiment of a chest
piece for establishing anatomically acceptable precordial elec-
trode positions for connection to electrocardiograph apparatus;
Figure 2 is an enlarged vertical sectional view taken
along the line 2-2 of Figure l;
Figure 3 is a plan view of one embodiment of a holder
for securing the chest piece of Figure 1 to the chest of a
patient;
Figure 4 is an enlarged pictorial view of one embodiment
of a spring connector for use with the chest piece of Figure l;
Figure 5 is a pictorial view of the chest piece of
Figure 1 secured to the chest of a patient by the holder of
Figure 3;
Figure 6 is an enlarged plan view showing the connection
of the spring connector of Figure 4 to the chest piece of
Figure l;
Figure 7 is a plan view of a second embodiment of a
chest piece;
Figure 8 is an exploded pictorial view of a second
embodiment of a holder for use with the chest piece of Figure 7;
Figure 8A is a view of one embodiment of a connector
wire for use with the chest piece o Figure 8;
$
Figure 9 is a pictorial view schematically illustrating
the connections of the holder of Figure 8 to a ten terminal
electrocardiograph recorder;
Figure 10 is a pictorial view schematically illustrating
the connections of the holder of Figure 8 to a five terminal
electrocardiograph recorder;
Figure 11 is a pictorial view of one embodiment of an
adaptor for use with a five terminal electrocardiograph;
Figure 12 is a schematic circuit diagram of the adaptor
Figure 13 is a plan view of a second embodiment of a
chest piece;
Figure 14 is a pictorial view of one embodiment of the
electrode of the present invention;
Figure 15 is a cross-sectional view of the electrode
of Figure 14 taken along line 15-15;
Figure 16 is a pictorial view in partial section of a
second embodiment of the electrode of the present invention;
Figure 17 is a pictorial view of the electrical connector
of Figure 16;
Figure 18 is a pictorial view of another embodiment of
the holder of the present invention;
Figure 19 is a cross-sectional view of the embodiment
of Figure 18 taken along line 19-19;
Figure 20 is a cross-sectional view of the embodiment of
Figure 18 taken along line 18-18;
Figure 21 is a pictorial view of another embodiment of
the holder of the present invention;
Figure 22 is a cross-sectional view of the embodiment of
Figure 21 taken along line 21-21;
Figure 23 is an elevation in partial section of a third
embodiment of an electrocardiograph electrode assembly;
Figure 24 is a cross-section of the embodiment of
Figure 22 taken along line 23-23;
Figure 25 is the cross-section of Figure 23 with a
sleeve and pin type connector in place therein;
Figure 26 is the cross-section of Figure 23 showing the
operation of a split sleeve and pin type connector;
Figure 27 is a pictorial view of another holder;
Figure 28 is a section taken along line 27-27 of Figure
26;
Figure 29 is a pictorial view of another embodiment of
the holder;
Fig~re 30 is a pictorial view of one embodiment of a
weight for use in the embodiment of Figure 28; and
Figure 31 is a pictorial view of an electrocardiograph
electrode assembly with a frame member for overlying the chest
of a patient.
DETAI~ED DESCRIPTION
As illustrated in Figure 1, a chest piece 22 may comprise
a strip 24 of expandable or stretchable material such as
rubber sheeting. Extending through the strip 24 are six spaced
electrodes designed Vl, ~72' V3, V4, V5 and V6 in accordance
with their positions. As best shown in the enlarged sectional
view through the electrode V6 in Figur 2, each electrode may
comprise a hollow metal sleeve or rivet member 26 estending
through the strip with the outer end (away from the patient's
skin) projecting beyond the adjacent surface of the strip at
26' to facilitate the attachment of leads as will be discussed
below. At each end of the strip 24, three transversely spaced
connector rings 28 are shown extending through the strip 24.
With reference to Figure 3, a holder 30 is preferably
formed of rigid wood or plastic material or the like although
it might in certain circumstances be of flexible fabric or
other material. The holder may include hooks 32 at each end
:
2~
corresponding in number and spacing to the connector rings of
the chest piece of Figure 1. The holder 30 extends around the
back of the patient so tha~ the hooks 32 thereon may engage
the connector rings 28 of the chest piece to hold the lattex
in place across the chest of the patient as shown in Figure 5.
A significant feature of the constru¢tion thus far de-
scribed is the disposition or locatlon of the electrodes Vl to
V6 on the chest of the patient. With the strip 24 of the chest
piece in an unstretched condition, these electrodes are spaced
suitably for engagement with the correct anatomic contact areas
for the precordial electrodes usually designated Vl, V2, V3,
V4, V5 and V6 on a chest of small size such as that o~ a ten
year old child. To facilitate positioning on the patient, the
strip of the chest piece may be provided with a vertical line
or mark 34 indicating the location for the mid-chest or mid-
sternum line and a horizontal mark 36 indicating the location
of the mid-nipple line. Thus, the vertical line is midway
between the electrodes Vl and V2 and the horizontal line is in
alignment with these electrodes.
With thè basic pattern for the electrodes based on the
measurements of a small chest as stated, the electrodes can
be made to automatically assume the correct anatomic location
on a larger chest by stretching the stretchable strip 24 the
appropriate amount in securing it to the patent. This is
readily accomplished by employing holders 30 of different
sizes, or with multiple hook locations, for securing the
chest piece in place on different size chests. Alternatively,
elastic strips of different flexibility might be used as a
holder.
Figure ~ shows a conductor 38 including a U-shaped
spring connector 40 for engaging electrodes 26 at the afore-
mentioned projecting portion 26' as shown in Figure 6. The
: ~ .
hollow construction of electrodes 26 permits the introduction
of conductive electrode paste from the outside of the passage
therethrough to the other end which contacts the skin of the
patient so as to provide a low-resistance contact between the
electrode and the patient's skin. The other end or the con-
ductor 38 may be provided with a spring wire adaptor 42 or
other suitable conventional connector for receiving a metal pin
connector at the end of a lead wire of the patient cable of an
electrocardiograph recorder. A single conductor 38 may be
moved from one electrode Vl to V6 to another or conductors may
be connected to all the electrodes simultaneously for operation
through an adaptor unit such as is hereinafter described in
connection with Figures 11 and 12.
Figures 7 and 8 illustrate, respectively, another chest
piece and a holder. With reference to Figure 7, the chest
piece includes a strip 122 of stretchable material similar to
the strip 24 of Figure 1 and is provided with electrodes 126
spaced therein in accordance with the appropriate precordial
anatomic positions Vl, V2, V3, V4 t V5 and V6 for a patient
having a small chest. Also, like the chest piece of Figure 1,
the chest piece of Figure 7 is stretchable across the chest of
a larger patient to automatically adjust the spacing of the
electrodes 126 to cause them to engage the corresponding
precordial anatomic positions for persons having larger chests.
Three connecting rings 128L and 128R are shown secured at the
left and right ends, respectively, of the strip 122 for
engagement by hooks on corresponding positions on a holder
member to be described in connection with Figure 8.
The chest piece 122 includes electrical conductors 130
individually making electrical connection between the six metal
electrodes 126 and the end connectors 128L and 128R. In Figure
7, the electrodes at precordial positions Vl, V2 and V3 are
-8-
.:
shown connected by the conductors 130 to the connector rings
128R for the patient's right side, which rings are labelled
Vl, V2 and V3, respectively. Similarly, the electrodes at
positions V4, V5 and V6 are connected, respectively, to the
connector rings 128L on the patient's left side designated
V4, V5 and V6. The electrical conductors 130 interconnecting
the electrodes and connector rings are preerably embedded in
the stretchable or elastic strip 122, although they may be
disposed on the surface of the strip opposite the surface
which contacts the patient's skin. It is also preferred that
the conductors be made flexible, as by employing a slight
helical or curved configuration, so that they may accommodate
to the changes in spasing of the interconnected electrodes and
connector rings when the chest piece is stretched to the
different lengths necessary for use in patients having chests
of different sizes.
The electrodes 126 may be hollow sleeve members extending
through the chest piece strip similarly to the electrodes 26
of Figures 1 and 2, whereby electrically conductive electrode
paste can be conveniently introduced into them from the outside
after the chest piece is installed to obtain a low-resistance
contact with the patient's body. Because of the internal
electrical connections to the connector rings, the electrodes
126 do not necessarily require outwardly projecting portions
such as are shown at 26' in Figure 2.
Figure 8 shows a holder for location at the back of a
patient to hold the chest piece in an adjustable position
according to the size and conformation of his chest and
facilitate making the necessary electrical connection to
electrocardiograph recorder equipment.
The holder includes a holder base plate 142, preferably
of rigid plastic material including an outwardly projecting
26
longitudinal bar 144 having downwardly and inwardly extending
bevelled sides 146. Longitudinal bar members 148R and 148L
have bottom slots 150 making a sliding fit over the longitudinal
bar 144 and further include transverse upper slots 152 with
upwardly converging, bevelled.edges 154. Transverse bar
members 156R and 156L are provided with corresponding projec-
tions 158 fitting into the slots 152 for transverse sliding
adjustment therein.
Bar 156R includes three metal hooks 160R, designed
Vl, V2 and V3, each connected to one of the wires in a five-
wire cable 162P~. Also two pin jacks RA (right arm) and RL
(right leg) are disposed on bar 156R and connected to the other
two wires of five-wire cable 162R. In like manner, bar 156L
includes three hooks, designated V4, V5 and V6 and two pin
jacks LA (left arm) and LL (left leg) connected individually
to five wires in five-wire cables 162L. The remote ends of
five-wire cables 162R and 162L extend into a terminal or
connector block 164 of non-conductive material with the ten
wires of the cables terminating in ten binding posts 166.
The construction of the holder is su¢h that the engage-
ment of the slots 150 of bars 148R and 148L with the base
plate 142 and the engagement of the slots in the bars 148R
and 148L with the projections on the transverse bars 156R and
156L is loose or frictionless to provide free movement or the
chest piece pulls the sliding bars of the holder together until
they touch the sides of the chest. The adjustable bars will
hold their adjusted positions with the chest piece 122 stretched
the desired amount and in the desired transverse position
through the pull of the chest piece.
In use, bars 148R and 148L are assembled on bar 144 with
their slots 150 in longitudinally adjustable engagement with
longitudinal bar 144. Also proiections 158 on transverse bars
--10--
156R and 156L are fitted into transverse slots 1~2 in bars
148R and 148L, respectively, for slidable transverse adjust-
ment therein. The chest piece is placed over the chest of the
patient and the holder under the back of the patient. The
connector rings 128R and 128L are engaged with hooks 160R and
160L, respectively. With the aid of the mid-sternum and mid-
nipple lines 134 and 136 on the chest piece 122, the blocks
148R and 148L and 156R and 156L are slidablY adjusted to so
stretch the flexible or stretchable strip of the chest piece
as to locate the respective electrodes 126 at the correct
percordial anatomic positions corresponding to Vl, V2, V3, V4,
V5 and V6 for the particular chest size of the patient~
Figure 8A illustrates a connector wire 168 for use in
connecting the pin jacks RA, RL, LA and LL to the extremities
of the patient. One end of a wire 170 terminates in a miniature
plug 171 for engagement with the aforementioned pin jacks while
the other end is provided with a standard ECG plug 172 for
engagement with extremity electrodes which may be of convention-
al type.
With the chest piece and holder assembled on the patient
as described, and the pin jacks RA, RL, LA and LL connected
through wire correctors 168 to extremith electrodes on the
right arm, right leg, left arm and left leg, respectively, the
binding posts 166 of the connector block 164 for the holder
will provide connections to each of the four extremity
positions and each of the six usual precordial positions.
Figure 9 shows schematically the electrical connections
of the form of the invention shown in Figures 7 and 8 to a
ten-texminal electrocardiograph conductor. Thus, the five-
wire leads 162R and 162L from the holdex 1~0 are connected to
the terminal block 164 and the ten binding posts 166 from the
block are connected by a ten conductor cable 174 to the
--11--
-
electrocardiograph 176. When the chest piece and holder of
Figures 7 and 8 are used with a five-terminal electrocardio-
graph recorder, the electrical connections are made as shown
in Figure 10.
Figures 11 and 12 show the adaptor as including five out-
put conductors extending to the five terminal, single V channel
electrocardiograph recorder. Four of these conductors extend
directly through the adaptor to the four extremity conductors
FL, LL, RA and RL while the fifth conductor is the V channel
conductor which may selectively be connected to each of the
p~ecordial leads Vl to V6. A manually controlled selector 184
is movable rrom a zero position 0 through connections to the
leads Vl and V6.
As illustrated in Figure 13, a chest piece 22 may
comprise a strip 24 of expandable or stretchable material
such as rubber sheeting. Extending through the strip 24 are
six spaced electrodes 226 designated Vl, V2, V3, V4, V5 and V6
in accordance with their positions~ The electrodes will be
described in greater detail in connection with Figures 14 and
15. The electrodes are adapted to receive an electrolyte
through apertures 228, which, when the chest piece is disposed
on the patient, open outwardly from the chest of the patient.
Terminal members 230, which may be rotatably mounted to the
electrode, are adapted to receive a cable plug from the
electrocardiograph machine.
As shown in Figure 13, the chest piece 22 may include
strip end members 232. Advantageously, the strip end members
232 may be detachably coupled to the stretchable strip 24 by
means of snap fasteners 234. The strip end members may carry,
for example, a buckle catch (not shown) or similar de~ice for
releasably engaging the holders or retainers hereinafter
described. Since both the strip end members and electrodes
-12-
~
are readily detachable from the stretchable strip, some or all
of the electrodes, and the strip end members can be replaced,
permitting the remaining components to be reused.
With continued reference to Figure 13, the strip 22 may
include a number of "stays" 236 similar to collar stays. These
stays are useful in reducing the reduction in the width of the
strip as it is stretched lengthwise across the chest of a
patient. They may be attached by any suitable conventional
means such as pressure sensitive adhesive.
Referring now to Figures 14 and 15 where the electrode
226 of Figure 13 is illustrated in greater detail, the
electrode may include a hollow tubular member 240 made of
electrically conductive material and terminate circular bell-
shaped flange portions 242. A pair of circular flanges 244
carried by the tubular member 240 may together form an annular
slot 246 configured and dimensioned to engage the edge portions
of an aperture in the sheeting material 22 to releasably
maintain the electrode 226.
A terminal 248 may be rotatably mounted on the tubular
member 240 and may be configured and dimensioned to receive
and frictionally engage a banana cable plug 250 connected to
an input terminal of a conventional electrocardiograph machine.
A thumb screw 252 may be provided to insure an electrical
connection with any electrical lead from an electrocardiograph
machine.
In operation, the bell or cup shaped portion 24~ may
be held against the chest of a patient by the stretch of the
sheet 22 across the chest of the patient. An electrolyte
paste may then be inserted through the top of the tubular
member 240 to contact the chest of the patent. The terminal
248 may, if rotatable, be positoned to any convenient orienta-
tion and may include a spring biased alligator clip or other
suitable electrical connecting means in lieu of the aperture
and thumb screw illustrated.
An alternate to the electrode 226 of Figures 14 and 15
is illustrated in Figures 16 and 17 where the electrode is
maintained in place in an aperature in the sheet 22 by a single
flange 252 and the bell or cup shaped terminator 254 of the
tubular member 56.
As shown in Figure 17, the connector 64 may be a flat
metal sheet rolled at one end to form a split sleeve for
insertion into the tubular member 256 to be there retained by
the spring action of the sleeve. The other end of the con-
nector 264 may be formed into two split sleeves 266 and 268
of different dimaeters to facilitate the insertion of banana
plugs of different sizes.
A holder for a chest piece such as that described in
connection with Figure 13 is illustrated in Figure 18. With
reference to Figure 18, the chest piece 269 may include strip
end members 270, formed with buckle catches 272 for insertion
into their respective buckle members 274 to thereby engage the
ends of the chest piece 269 with the holder 268. The holder 68
may include a first belt 76 threaded in a first direction
through a base member 78, and a second belt 80 threaded in
the opposite direction through the base member 78.
Ad~antageously, the buckle members 274 and belts 280
and 282 may be attached to the base member 278 in the manner
depicted in Figure 19, where one end 284 of the belt may be
anchored to the base member 278. The belt may then be disposed
about a roller 286 within the buckle member 274 and be threaded
through an elongated channel 288 in the base member. In order
to tighten the chest piece 269, the end 282 of the belt may be
pulled to draw the buckle member 274 toward the anchored belt
end 284 to be maintained in position vis-a-vis the belt by
-14-
'$
frictional engagement between the buckle member, the belt,
and the roller 286.
Referring now to Figures 21 and 22, the holder 300 may
include a first belt 302 threaded through a channel in base
member 304. One end of the belt 302 may be provided with a
snap coupling 306 adapted for releasably engaging the strip
end piece 308 of the chest piece 310. A second strip end piece
312 of the chest piece 310 may be formed with a buckle catch
314. The buckle catch may be releasably engaged by the buckle
member 316 carried by a second belt 318. The second belt may
engage a roller 320 which redirects the second belt 318 so
that a portion thereof is nearly parallel to a portion of the
first belt 302. The ends of the first and second belts may be
joined to facilitate stretching of the chest piece across the
chest of the patient.
In operation, the h~lder 300 may be disposed behind the
patient prior to electrocardiograph monitoring. The strip end
member 308 may be engaged to the snap fastener 306 of the belt
302. The chest piece 310 may be placed about the chest of the
patient and loosely secured in position by buckling the buckle
catch 314 with the buckle member 316. The electrodes may be
positioned and maintained in contact with the precordial
anatomic positions on the chest by pulling on the joined ends
of the belts 302 and 318 in the direction of the arrow 324.
A quick release seat belt type locking mechanism 326 may be
provided to permit movement of the belts 302 and 318 only in
the approximate direction of the arrow 324. However, the belts
may be quickly released.
A third embodiment of an electrode is illustrated in
Figure 23 where the body of the electrode is provided with a
single generally circular flange 350 radially outwardly
extending from a tubular upper portion 352. A cup shaped
-15-
lower portion 354 cooperates with the flange 350 to prevent
the slippa~e of the electrode fro~ the stretchable strip 22.
The body of the electrode may be of non-conducting
material which is desirably resilient to a minor degree. The
upper portion is also provided with one or more lateral bores
356 having a portion common with the axial bore 358 as is
illustrated more clearly in Figures 24-26.
As shown in Figure 23 and Figure 25, a sleeve 360 of
electrically conductive material may be inserted into the bore
358 of-the non-conductive body of the electrode, the sleeve
360 extending from a point along the uppermost lateral bore
to a point just above the bottom of the cup shaped portion of
the electrode.
As is illustrated in Figure 25, a lead of an ECG machine
may terminate in an electrically conductive pin 362 adapted for
insertion into the lateral bore 356 to be removably held in
pressural engagement with the sleeve 360 by the physical
configuration of the bores 356 and 358 and/or the resiliency
of the material of the electrode body.
A fourth embodiment of an electrode is illustrated in
Figures 27 and 28, where the body 370 is desirably molded out
of a plastic material into a generally tubular configuration.
As shown in the figures, an electrically conductive thin-
walled tube 372 extends substantially the length of the body
370 and may terminate in a bell shaped portion in contact with
the skin. The lower end of the body is generally in the shape
of a truncated cone to form a cavity 374 for electrolyte
introduced into the upper end of the tube 372.
The sides of the body 370 are desirably formed to provide
notches 376 and 378 at different heights from the bottom of the
body. When the present invention is utilized on women with
large breasts, greater extension of the electrodes beneath the
-16-
belt it required for good electrical contact in the V2 and V6
positions. Notch 378 is desirably used in such circumstances.
As also shown in the drawings, two lateral apertures
380 and 382 are provided into which the tube 372 extends.
These apertures 380 and 382 are desirably o~ different sizes
to accommodate bayonet or banana plugs of differing sizes.
The body 370 of the electrode is desirably split into the
apertures 380 and 382 to provide a resilient spring action in
holding the plug from the electrocardiograph machine into
pressural engagement and thus good electrical contact with
the tube 372.
It is important to note that the tube 372 may extend
upwardly from the top of the body 370 so that a suction cup
(not shown) of a conventional type may be attached for use in
creating a suctional attachment of the electrode to the patient.
- Figure 29 is a pictorial view of an electrocardiograph
electrode assembly including means for applying a downward
force to ends of an elastic chest piece such as that described
in connection with Figure 13. The chest piece 330 of Figure 29
may be stretched to place the electrodes in contact with the
proper precordial anatomic positions on the chest of a reclin-
ing patient by placing the chest piece 330 on the chest of the
patient and disposing weights 332 on either side of the patient
to exert a downward force on ends 334 of the chest piece.
The weights may take any desired form but it has been
found advantageous for comfort and safety to use a "bean bag"
weight such as illustrated in Figure 30. With reference to
Figure 30, the weight may include a fabric bag 336 of particu- ;
late material such as dried beans or the like connected by any
suitable conventional means such as the illustrated fastener
338 to a rigid retainer 139 to which the free ends of the
chest piece might be buckled.
The embodiment of Figure 29 is particularly desirable
where movement of the patient to place some retaining means
behind his chest may result in injury or discomfort. Another
embodiment not requiring movement of the patient is illus-
trated in Figure 31 where the buckle 340 includes arcuate
members 342 for bridging the chest of the patient. A surface
344 may be provided on either side of the chest of the patient
for receiving weights sufficient to stretch the chest piece
346. The chest piece 346 may be releasably engaged to the
retainer 340 by snap fasteners 348.
The electrodes of the present invention may be configured
with notches on two of four sides and be smooth on the other
two sides to facilitate retaining of the electrodes in a canted
position by an aperture in the belt. This may be particularly
desirable for the Vl, V2 and V6 positions on certain type
chests.
In lieu of a liquid or paste electrolyte, gel pads may
be used. These may be held to the electrodes by suction prior
to placing the belt on the chest after which a new suction may
be drawn through the gel pad to the chest.
From the foregoing description, it will be apparent that
the present invention provides a number of features which
increase the ease and speed with which electrocardiograms can
be made and at the same time decrease the chance of errors
and reduce the cost. The stretchable chest piece provides
a means for rapidly and repeatedly locating the precordial
electrodes at the correct anatomic position on a patient's
chest. The described embodiments are to be considered in all
respects illustrative and not restrictive, the scope of the
invention being indicated by the appended claims rather than
by the foregoing description, and all changes which come
within the meaning and range of equivalency of the claims
are therefore intended to be embraced therein.
.
