Inflatable Balloon-type Pacing Probe

Abstract

A catheter device having a tubular assembly with a forward probe portion including spaced proximal and distal members having electrodes secured thereto and being provided with inflatable means comprising a balloon member interconnecting said members; and fluid receiving means in communication with the probe portion for dilating said balloon member upon exposure to fluid introduced under pressure through the fluid-receiving means.

Description

This invention relates generally to insertion probes and/or catheters and, more specifically, to an inflatable balloon-type pacing probe capable of being moved within body cavities and/or blood vessels of persons and animals.

The medical professions have enjoyed considerable success over the years using devices such as catheters and probes, which are introduced or inserted into body channels and blood vessels. Catheters are most frequently employed within the urinary tract to withdraw urine from the bladder, for example, by passing the catheter through the urethra or passage through which urine is normally discharged. Probes, on the other hand, which are not provided with openings to receive body fluids, must also be capable of insertion into and movement within relatively small body cavities, such as blood vessels, without injuring vessel and organ tissues or causing discomfort to the patient or animal being treated.

While the present invention is principally directed to probes for use in pacing or regulating the heartbeats of a person or animal, it is contemplated and within the scope of this invention to provide medical personnel with insertion apparatus such as probes and the like equipped with structural safety features which minimize or eliminate tissue damage and discomfort.

Balloon-type insertion devices are well known to the art. In many instances a bag or balloon formed of rubber other stretchable material is provided on catheters, for example, to retain the catheter within a body channel by inflating the balloon once the device is properly located. The expanded bag or balloon contacts the tissue walls defining the body channel and further movement into or out of the channel is prevented. Such insertion devices known to the art, however, often cause considerable tissue damage and patient discomfort both when being inserted as well as when being inflated. Although such devices are fabricated of relatively flexible and resilient material, most of these flexibility and resilience characteristics are exhibited in transverse directions with respect to the relatively longitudinal axes of these normally elongated tubes. Thus, while the tube of a catheter will easily bend to conform to the contour of a body channel, there yet will be an uncushioned relatively longitudinal transfer of forces to the forward tip or end of this tube which are required to advance it upon insertion.

Another problem associated with conventional balloon-type insertion devices concerns itself with the inflation of the balloon. Here again, since conventional devices already described are formed with a balloon extending annularly around a continuous portion of the tubing near or adjacent its forward tip, the presence of a continuous length of tubing prevents substantial elongation or shortening of this tube when body tissue is contacted by either the forward tip of this tubing or the expanded balloon. Forces are thus transmitted directly to the tissue without being cushioned and, as is sometimes the case, tissue walls are damaged or even punctured or torn.

Accordingly, it is an object of the present invention to provide a balloon-type, flow-directed insertion device equipped with safety cushioning means for preventing tissue damage.

Another object of the present invention is to provide a novel balloon-type pacing probe for use in stimulating the heart's muscles.

Yet another object of this invention is to provide a segmented insertion device for use within elongated cavities wherein the segments are joined by an inflatable balloon adapted to isolate forces from being transmitted between segments.

A further object of my invention is to provide a segmented balloon-type pacing probe for use within body blood vessels, and which is of a predetermined relatively small diameter with respect to the diameter of said blood vessels, such that the normal flow of blood is not restricted during its use.

Yet another object of the present invention is to provide a flow directed, balloon-type pacing probe for use in indicating and/or evaluating heart block Adams-Stokes seizures, marked bradycardia, ventricular tachy-arrhythmias and digitalis induced arrhythmias.

The present invention fulfills the aforementioned objects and overcomes limitations and disadvantages of prior art solutions to problems associated with this art. According to one aspect of the invention, an elongated, relatively flexible tubular assembly is formed with a hollow resilient insertion tube extending between forward and rearward ends thereof. The assembly is preferrably provided at its forward end with a multi-electrode or multi-polar pacing probe capable of regulating the frequency of heartbeats in response to signals generated outside the body. This probe is introduced, for example, into the right shoulder region of the patient via a 14 gauge cannula or cut-down. The hollow insertion tube is formed in two spaced segments of different lengths which are mechanically interconnected by an inflatable balloon which, in turn, extends annularly about the space between said segments. The longer or proximal tube segment carries a proximal electrode to which an electrical conductor is secured. The shorter or distal tube segment carries a distal electrode to which another electrical conductor is soldered and which is electrically insulated from the proximal electrode and its respective conductor. Both the proximal and distal electrodes serve to stimulate the heart in response to impulses carried to them from remote signal-generating apparatus via said conductors.

The invention will be more clearly understood from the following description of a specific embodiment of the invention, together with the accompanying drawings, wherein similar reference characters denote similar elements throughout the several views, and in which:

FIG. 1 is a fragmentary view of the entire probe assembly according to one embodiment of the invention;

FIG. 2 is an enlarged fragmentary view of the insertion balloon-type tip or probe portion of the invention shown in FIG. 1;

FIG. 3 is a cross-sectional elevational view of the insertion tip or probe portion of FIG. 2, illustrating the balloon in its inflated condition; and

FIG. 4 is an enlarged cross-sectional elevational view looking along line 4--4 of FIG. 3.

Referring now in more detail to the drawing, in FIG. 1 a balloon-type bi-polar pacing insertion assembly, generally designated numeral 10, is shown to include elongated hollow tubing 12 which extends between a valved adaptor assembly 14 and a probe assembly 16.

Tubing 12, is a preferred embodiment of the invention, consists of a chemically and organically non-porous material such as Corolan which is manufactured by the Electro-Catheter Corporation of Rahway, New Jersey, and which is capable of being sterilized by heat or chemical action, and which further has a substantially smooth, low-friction surface so as to be capable of easy insertion into and through a body cavity, such as a vein. Other suitable materials may be substituted for tubing 12 and are contemplated by this invention, including, without limitation, radio opaque vinyl-type tubing which is visible by X-ray. Tubing 12 is relatively flexible to permit its passage through irregular body channels such as the veins leading to the heart.

Valved adaptor assembly 14, as shown in FIG. 1, consists of a Y-shaped plastic or rubber housing 18 formed with a leg or end 20 which receives and is secured air-tightly to the rearward end of tubing 12, such as by potting or cementing. Another leg or end 22 of housing 18 holds two insulated electrical wires or conductors 24 and 26, which extend from housing end 22 at their most rearward ends to male electrical connector pins 28 and 30, respectively. Connector pins 28 and 30 are of a conventional type which will matingly engage electrical sockets (not shown) of remote apparatus, described in more detail below. Housing legs or ends 20 and 22 serve as strain-reliefs in receiving tubing 12 and conductors 24 and 26 such that the possibility of breakage or fracture is minimized. Legs or ends 20 and 22 further serve as air-tight junctions, thereby preventing the undesirable flow of air between the interior of adaptor assembly housing 18 and the environment.

Larger leg or end 32 of housing 18 is formed with a tapered opening 34 which is adapted to receive the forward end of a vented-type syringe, or air duct, designated reference numeral 34 in FIG. 1. Thus, air or another pre-selected fluid may be introduced under pressure through opening 34, such as by moving the plunger of a vented syringe 36 forward within its barrel, and thereafter through hollow tubing 12 toward probe assembly 16. Vented syringe 36 is preferably a 21/2 cubic centimeter (cc) syringe formed with a hole through its barrel at a location corresponding to 11/2 cc, thereby preventing the possibility of bursting balloon 70, described below. No more than 11/2 cc of fluid is thus introduced. Adaptor assembly 14 is preferable equipped with a valve of a type known to the art, for preventing undesirable fluid or air flow through the housing 18, as well as to enable personnel to control the fluid pressure within tubing 12.

Looking now at probe assembly 16 in FIGS. 2 and 3, it is seen that assembly 16 comprises two forward segments of tubing 12 which, for convenience, are designated proximal tubing segment 38 and distal tubing segment 40 in FIG. 3. The adjectives proximal and distal are hereinafter used merely to denote locations with respect to valved adaptor assembly 14. Distal segment 40 is substantially shorter than proximal segment 38 and is preferable formed by severing a predetermined length of tubing from the forward end of tubing 12.

Proximal tubing segment 38 terminates at a forward end 42 which defines an opening 44. Distal tubing segment 40 extends between its rearward end 46 and a forward end 48, both ends defining openings 50 and 52, respectively. Forward end 42 and rearward end 46 are spaced from one another a predetermined distance which, in a preferred embodiment of the invention, is three (3) millimeters. It is within the scope of this invention for this distance to vary, preferably between two (2) and five (5) millimeters, although my invention contemplates a spacing of from one (1) to ten (10 ) millimeters.

Probe assembly 16 further includes an annular proximal electrode 54 which is bonded to tubing segment 38 a small distance from forward end 42. Proximal electrode 54 is formed of an electrically conductive metal, preferably platinum. Similarly, a cup-shaped distal electrode 56 is bonded to distal tubing segment 40 such that the interior of distal electrode 56 annularly surrounds and encloses forward end 48 of segment 40. Distal electrode 56 is preferably made of platinum or other suitable electrically conductive material, and is formed with a hollow nose portion 58 which constitutes the forwardmost tip of insertion assembly 10. The outer surfaces of nose portion 58 are smooth and frictionless, and are rounded to provide a blunt convex surface designed not to irritate, puncture or damage body tissue.

A predetermined quantity of solder 60 located within the hollow nose portion 58 of distal electrode 56 firmly, both mechanically and electrically, secures distal electrode 56 to a central cabe assembly 62 which, in turn, extends relatively longitudinally through the confines of tubing from adaptor assembly 14 to segments 38 and 40 and thereafter to solder 60. It is important here to emphasize the importance of the strong mechanical locking of distal electrode 56 to the remainder of the insertion assembly 10 since, as it should be apparent, separation of the distal electrode and/or tubing segment 40 within the circulatory system of a patient could result in substantial injury, or possibly death. The firm bonding of distal electrode 56 to tubing segment 40, coupled with the firm soldered bond of distal electrode 56 to cable assembly 62 effectively precludes this danger. The presence of an inflatable bag or balloon 70, shown in FIGS. 2 and 3 are described in more detail below, serves to yet further eliminate this danger of separation.

Cable assembly 62 preferably comprises a Teflon coated, brass plated electrical conductor 64, such as copper (Teflon is a registered trademark of the E. I. duPont de Nemours, Inc. of Wilmington, Delaware). Assembly 62 is relatively flexible and easily bends such that forces applied directly to the nose portion 58 of distal electrode 56 will result in a lessening of the distance between tubing segment ends 42 and 46. A conductive wire 68 extends through proximal tubing segment 38 of elongated tubing 12 to and through an aperture 66 formed through the wall of proximal tubing segment 38, and thereafter to and in mechanical and electrical contact with proximal electrode 54, such as by soldering or brazing. Conductor 64 and wire 68 are electrically insulated from one another by virtue of the presence of the Teflon coating around the length of conductor 64. Conductor 64 and wire 68 are mechanically and electrically connected within adaptor assembly 14 to conductors 24 and 26, respectively, and thus, also to connector pins 28 and 30, respectively. It is contemplated by and within the scope of the present invention to substitute a single conductor or wire in the place of conductors 64 and 24; and similarly, to substitute a single conductor or wire in the place of wire 68 and conductor 26.

An inflatable bag or balloon 70 is shown relaxed in FIG. 2 and inflated in FIGS. 3 and 4. Balloon 70, in a preferred embodiment of this invention, comprises a latex tube which extends annularly over and in firm air-tight, bonded contact with the outer surfaces of both forward end 42 of tubing segment 38 and rearward end 46 of tubing segment 40. Bonding of the inner extremities of balloon 70 to tubing segments 38 and 40 may be accomplished by cementing, heat-induced welding or fusion, or other suitable conventional means. Balloon 70 may be fabricated from suitable stretchable materials other than latex, which are inert and which are capable of being sterilized by heat or chemical action.

It should now be apparent that fluid, preferably air, introduced under predetermined pressures into elongated tubing 12 by syringe 36, for example, will cause balloon 70 to gradually stretch or expand both radially outwardly to a diameter approximately one-quarter to one-half the diameter of the blood vessel within which it is situated, as well as longitudinally from the relaxed position shown in FIG. 2 to that shown in FIG. 3. The longitudinal expansion of balloon 70, in turn, causes distal electrode 56 to be biased away from proximal electrode 54, such that the spacing or distance between ends 42 and 46 of tubing segments 38 and 40 is increased. Upon deflation of balloon 70, segment 40 will once again return to its original spacing from segment 38.

In use, the probe assembly 16 of insertion assembly 10 is caused to enter a blood vessel through a placement or percutaneous needle inserted through an incision made in the skin of a patient, and probe assembly 16 together with portions of tubing 12 are manipulated through the blood vessel toward the heart. This is accomplished with the balloon 70 completely relaxed and without the presence of pressures greater than atmospheric pressure within tubing 12. Either by noting the length of tubing 12 inserted, or by monitoring of the location of probe assembly 16 in a conventional manner known to the medical arts, a relatively precise positioning of the proximal and distal electrodes is accomplished. Once positioned within the superior vena cava balloon 70 is inflated in the manner heretofore described and the inflated probe assembly is advanced to the right ventricle of the heart, whereupon the balloon is deflated and the probe assembly is stabilized in the apex of the ventricle. The position of the probe can be verified by X-ray of the patient's chest, or fluoroscopy.

Connector pins 28 and 30 can be mechanically and electrically connected to an electrocardiograph apparatus, so that monitoring of the position of the distal electrode has been enabled, and thereafter connected to an impulse generator, such as a Pacemaker, a registered trademark of the Electro-Catheter Corporation of Rahway, New Jersey. Electrical impulses generated by the Pacemaker are carried to proximal and distal electrodes 54 and 56, thereby stimulating the rhythmic contractions within the heart commonly known as heartbeats.

During the insertion of the probe, nose portion 58 may come into contact with body tissue on its journey towards the heart, due to the irregular path defined by the blood vessel. This contact with body tissue will impede the progress of the probe and will both result in displacement of the tissue, and will create forces on the probe tip or nose. The result will be movement of distal tubing segment 40 and proximal tubing segment 38 towards one another. This safety feature of relative movement as between these segments prevents the puncturing of body tissue and is facilitated by both the presence of the space between the segments, as well as the resilient compressibility of the relaxed balloon 70.

Thus, forces existing in proximal tubing segment 38 necessary to advance the probe will not be transmitted directly to body tissue, but will be absorbed by the cushioning effect of the collapsible balloon 70.

Yet another novel safety feature of this invention resides in the characteristics exhibited by probe assembly 16 once it has been properly positioned and it is desired to inflate balloon 70. Upon inflation of balloon 70 in the manner described, should the outer walls of the balloon gradually contact and come to bear against the inner body tissue walls defining the cavity within which the probe assembly has been positioned, increases in pressure within tubing 12 will result in corresponding increases in bearing forces against this wall tissue as a result of the balloon's attempts to expand under this pressure. The present invention prevents these bearing forces from becoming dangerously excessive by permitting elongation of balloon 70 when restrained by body tissue from expanding outwardly or transversely from the axis of tubing 12, and by permitting a separation of tubing segments 38 and 40 from one another by virtue of their resilient interconnection with balloon 70. It is also significant that once balloon 70 has been inflated, movement of either of segments 38 or 40 will not be carried directly to the body tissue, but will result in a flexing of the resilient pressurized balloon.

Both in the case just described where balloon 70 is relaxed, as well as in the case where the balloon is being inflated, probe assembly 16 and its elements exhibit a greater flexibility and resilience than heretofore made possible in the art. Greater angular displacements of distal electrode 56 from its normal longitudinal axis are possible with this electrode than are possible with known, more rigid continuous tubings. Furthermore, FIG. 3 clearly illustrates the fact that less angular and shear stresses will be present at the points of securement of balloon 70 to tubing segments 38 and 40 than in prior art-type balloon devices, due to the break or gap between these segments. The ability of segments 38 and 40 to move away from one another greatly relieves any stress concentrations at the points at which the annular balloon joins these segments.

While the invention has been described for a single pole or bi-polar pacing probe for use in persons, it is contemplated that the safety features of the invention have considerable advantageous use in veterinary medicine. A single pole device may be employed wherein a second electrode is positioned on the patient's skin. It is also contemplated and within the scope of this invention that a balloon-type probe strucure of the type described may be used in non-pacing medical applications, such as the curing of an embolemia within a person or animal, by utilizing the inflatable balloon 70 to remove a clot from the circulatory system.

The embodiment of the invention particularly disclosed is presented merely as an example of the invention. Other embodiments, forms and modifications of the invention coming within the proper scope of the appended claims will, of course, readily suggest themselves to those skilled in the art.

Claims

What is claimed is:

1. A pacing and sensing catheter device for use within body cavities, comprising: an elongated tubular assembly formed at a forward end thereof with a probe portion adapted to be inserted into and moved within said body cavities, said tubular assembly being further formed at a rearward end thereof with means communicative with said forward end for receiving a fluid; said probe portion including spaced proximal and distal members and proximal and distal electrodes secured to said proximal and distal members, respectively; a first conductor electrically connected to said proximal electrode, a second conductor electrically connected to said distal electrode, and said first and second conductors being electrically insulated from each other; inflatable means formed of an elastic material secured to and interconnecting each of said spaced proximal and distal members; and said inflatable means, comprising a balloon member adapted to be inflated upon fluid introduced under pressure through said fluid receiving means, whereby the forward end of said probe portion is resiliently mounted for inhibiting the transfer of forces between said proximal and distal members.

2. The device according to claim 1, wherein said first and second electrical conductors are elongated and extend in spaced relationship within said tubular assembly.

3. The device according to claim 2 for use with remote heartbeat pacing apparatus, further comprising first and second electrical connectors secured to said first and second conductors, respectively, for electrically interconnecting said proximal and distal electrodes with said remote apparatus.

4. The device according to claim 3, wherein said proximal and distal members comprise spaced segments of said elongated tubular assembly, said proximal member being substantially longer than said distal member and being formed with a forward end which defines an opening communicative with interior walls of said balloon member, said distal member extending between forward and rearward ends thereof which define foward and rearward openings, respectively, the forward end of said proximal member and the rearward end of said distal member being disposed in variably juxtaposed relationship with respect to one another.

5. The device according to claim 4, wherein said balloon member is secured to and extends between outer annular surfaces of said proximal and distal members adjacent the juxtaposed ends thereof.

6. The device according to claim 5, wherein said proximal electrode comprises an annular platinum sleeve secured to the outer surface of said proximal member, said proximal member being formed with an aperture through which said first electrical conductor extends to said proximal electrode, said distal electrode comprising a cup-shaped platinum member surrounding the forward end of said distal member and being secured to the outer annular surface of said distal member, said second electrical conductor extending from within said proximal member through the rearward and forward ends of said distal member, and being electrically connected to said cup-shaped distal electrode by a soldered deposit disposed within and in electrical contact with the inner portion of said cup-shaped distal electrode.

7. The device according to claim 1, wherein said fluid receiving means comprises an adaptor formed with an opening which is adapted to matingly accept an end of a fluid bearing conduit.

8. The device according to claim 7, further including a vented syringe adapted to be sealingly connected to said fluid bearing conduit for pressurizing said balloon member to a pre-determined value.