WO2005007228A1

WO2005007228A1 - Ultrasonically marked delivery system for left heart pacing lead

Info

Publication number: WO2005007228A1
Application number: PCT/HR2004/000018
Authority: WO
Inventors: Branko Breyer; Ivo Cikes
Original assignee: Branko Breyer; Ivo Cikes
Priority date: 2003-07-18
Filing date: 2004-07-05
Publication date: 2005-01-27
Also published as: HRP20030588A2

Abstract

A method of ultrasonic guidance of the aiming and steering of the pacing lead into the coronary vein via the coronary sinus (CS) is disclosed. The aim is to place a pacing electrode into the left coronary vein enabling left heart pacing with or without concurrent right heart pacing. The placement may be done via the coronary sinus. The procedure must include visualization of the coronary sinus, preferably by ultrasound scanning, localization of the pacing catheter tip, directing - steering the tip along the CS axis and thus its placement into the coronary sinus. A marking piezoelectric transducer is mounted at or near the tip of the steerable delivery catheter that we want to localize in the vicinity of the coronary sinus. When this piezoelectric transducer comes within the scanning plane of an ultrasonic scanner, the pulses transmitted by it hit the said marker transducer. Such signals can in different ways be used for generation of visible guiding marks on the scanner screen. A representative method of such application is the use of a transponder connected to the said ultrasonic transducer. Additionally an ultrasonically marked wire, comprising an ultrasonic transducer at its tip may be implanted into the left ventricular venous system through said catheter. The wire is used to guide the pacing electrode, which is slid over the wire into the coronary vein. In this case a second transponder is used to ultrasonically control the placement of the guide wire into the left coronary vein system.

Description

Ultrasonically marked delivery system for left heart pacing lead

Technical field

This invention relates to cardiac therapy, particularly to the guiding apparatus for systems for biventricular pacing and resynchronization. More particularly, the invention pertains to the system for guiding procedures performed with biventricular pacemaker systems.

Summary of the invention

Ultrasonic guidance of indwelling of the pacing lead into left coronary vein via the coronary sinus (CS) is solved. The ultrasonic guidance essentially simplifies positioning of electrodes for biventricular pacing for the purpose of resynchronization of the heart. The system and the method consist of a specific ultrasonically marked application catheter set, ultrasound transponders and an echographic ultrasound scanner. In the first embodiment the procedure includes steering of an ultrasonically marked steerable catheter to the ostium of the coronary sinus, positioning of a delivery catheter at the ostium of the CS, positioning of a guide wire into the CS and further into left coronary vein and finally positioning of a pacing lead into the left coronary vein over the said guide wire. The tip of the steerable catheter is ultrasonically marked and visualized on the ultrasound scanner screen with the help of a transponder. The same ultrasound scanner is used for visualization of the coronary sinus and directing - steering the said ultrasonically marked tip into CS ostium. A delivery catheter is slipped over the said steering catheter and pushed all the way to the ostium of the CS up until the ultrasonic mark disappears from the scanner screen, which indicates that the marker transducer is masked by the delivery catheter pulled over it. Once the delivery catheter is in place, the steerable catheter is extracted and a guide wire is pushed through it into the CS and further into left coronary veins. A pacing lead is advanced over the guide wire into the left coronary vein and the delivery catheter and the guide wire are retracted. In the second embodiment the procedure includes steering of an ultrasonically marked steerable catheter to the ostium of the coronary sinus, positioning of a delivery catheter at the ostium of the CS, positioning of an ultrasonically marked guide wire into the CS and further into left coronary vein and finally positioning of a pacing lead into the left coronary vein over the said guide wire. The tip of the steerable catheter is ultrasonically marked and visualized on the ultrasound scanner screen with the help of a first transponder. The same ultrasound scanner is used for visualization of the coronary sinus and directing - steering the said ultrasonically marked tip into QS ostium. A delivery catheter is slipped over the said steering catheter and pushed all the way to the ostium of the CS up until the ultrasonic mark disappears from the scanner screen, which indicates that the marker transducer is masked by the delivery catheter pulled over it. Once the delivery catheter is in place, the steerable catheter is extracted and an ultrasonically marked guide wire is pushed through it into the CS and further into left coronary veins. The ultrasonically marked guide wire is connected to a second transponder, which makes possible positive localization of its tip within the left coronary vein system when imaged with the said ultrasound scanner. A pacing lead is advanced over the guide wire into the left coronary vein and the delivery catheter and the guide wire are retracted. The present device and procedure greatly simplifies and makes safer the cannulation of the ostium of the coronary sinus and all subsequent procedures for positioning of a pacing lead into the left coronary venous system.

Background and Prior Art

Technological problem to be solved is ultrasonic guidance of the positioning of the pacing lead into the coronary blood vessel via the coronary sinus (CS) in order to facilitate biventricular pacing for the purpose of resynchronization of the heart. The procedure consists of placing a pacing electrode into one of the coronary veins enabling left heart pacing with or without concurrent right heart pacing. The endovenous placement must be done via the coronary sinus. The procedure must include visualization of the coronary sinus, localization of the pacing catheter tip, directing - steering the tip enabling its placement into the coronary sinus. The procedure as done today includes bringing a catheter with its tip leaning against the CS, positioning of a delivery introducer sheath onto the CS over the said steerable catheter, withdrawal of the said catheter, positioning of a guide wire into the cardiac vein via the introducer and through CS, indwelling of the pacing lead over the guide wire into one of the left coronary veins and finally removal of the guide wire and of the introducer sheath. The procedure is sometimes done only utilizing the preshaped delivery introducer without the steerable catheter. The procedure is sometimes done utilizing the steerable catheter. This procedure is at the present done with X-ray guidance with considerable difficulty. This leaves the operator with the problems of three-dimensional real-time visualization of the coronary sinus and of the radiological hazard of such a procedure. The possibility of using non-invasive ultrasound is the object of this invention. At the present, however, the procedure is normally controlled by means of the radiographic imaging. Serious investigations confirmed that X-ray radiation exposure is significant and may be hazardous (H. Calkins et al.: "Radiation Exposure During Radio frequency Catheter Ablation of Accessory Atrioventricular Connections." Circulation 1991 ;84:2376-2382.). Disadvantage of X-ray methods is poor imaging of soft tissues, i.e. papillary muscle, interventricular septa, and so forth. As an alternative, ultrasonic imaging is well suited for imaging of soft tissues, but has the disadvantage of imaging in one plane tomographically. The ultrasonically marked catheters and cardiac pacing leads have been described in the U.S. Patents to Breyer et al. Nos. 4,697,595 and 4,706,681 respectively. The method of use of the said devices is explained in the papers by B. Breyer and I.Cikes: Ultrasonically marked catheter - a method for positive catheter position identification, Med. Biol. Eng. & Comput., 1984: 12: 268 and by B.Breyer and B.Ferek-Petric: Possibilities of ultrasound catheters, Int. J. of Cardiac Imaging, 1991 : 6: 277. Such systems enable the echocardiographic guidance of the procedure as well as the exact localization of the lead tip. If the catheter tip is marked by an ultrasonic transducer, the exact position of the catheter tip can be identified. Other methods of positioning electrotherapy, particularly ablation catheters to desired places have been attempted as well as in U.S. Patent Nos. :4, 660, 571 to Hess and Kovacs, 4,979,948 to Geddes et al., 4,522,212 to Gelinas et al., 4,628,937 to Hess and Tarjan, 4,940,064 to Desai, and in particular U.S. Patent No. :4, 699, 147 to Chilson and Smith where multiple basket electrode holders arrange the electrodes throughout the inner heart chamber surface. There exist trials to solve the problem using optical guiding as in U.S. Patent No. 4,928,695 to Goldman et al. As another attempt to solve the guiding problem is to refrain totally from imaging and rely on electrical recording as in U.S. Patent ns.:4,974,162 to Siegel et al. and U.S. Patent No.:4,641 ,649 to Walinsky et al., or magnetic mapping as in U.S. Patent No. :5, 056, 517 to Fenici. These approaches have the disadvantage of not directly relating to the anatomical position, but may be very successful in conjunction with some other means of anatomical localization. As far as it is known to the inventors, none of the available systems enables the continuous monitoring of the contact between the electrode and the cardiac tissue although there exists a proposed solution to the problem by way of fixation disclosed in U.S. Patent No.:4,832,048 to Cohen. Attempts to ultrasonically monitor the damage inflicted to arteriosclerotic plaques via a laser therapy catheter have been disclosed in U.S. Patent Nos.:4,576,177 to Webster and 5,010,886 to Passafaro et al. where in the latter there is a complete intracavitary ultrasound imaging system combined within the catheter. A particular example of this approach is one by Yock in U.S. Patent No. 5,000,185 where the advance of the intracardiac ablation is monitored by an intracardiac imaging system. The disadvantage of the two latter methods is the very restricted fields of view of high frequency (15 - 30 MHz) imaging systems, as well as their problematic imaging capability for metaloplastic structures of actual ablation catheters. Another possibility with ultrasound systems has been disclosed in U.S. Patent No 4,936,281 to Stazs and comprises a combined angioplasty catheter combining RF electrodes and an ultrasound transducer at the tip, which is designed to be used for A mode imaging or Doppler measurements. From the standpoint of localization this system is equivalent to the said disclosures by Yock, Webster and Passafaro, i.e. the localization and orientation problem remains to be solved. A pacing lead that is useful for transvenous pacing of the left ventricle is described in US Pat.No. 6,714,823. The delivery system includes a J-tipped guide wire insertable into the right atrium or right ventricle from a cephalic or subclavian vein, a sheath with preformed curve, and a dilator, wherein the sheath, with the dilator positioned therein, can be moved over the guide wire placed into the right ventricle, the guide wire and dilator thereafter removable to cannulate the ostium of the coronary sinus or a distal cardiac vein, and provide guidance for a pacing lead that can be moved through the sheath into the coronary sinus. A lead claimed by US Pat.No. 5,476,498 includes a preformed section having a resiliently coiled configuration. The coiled section is a left-handed turned coiled section, which provides superior positive fixation of the lead as compared to, right- handed turned coiled sections for use in the coronary sinus and great cardiac vein. Side access "over the wire" pacing lead is disclosed in US Pat. No. 5,803,928. Another lead for pacing and/or sensing the heart from within the coronary veins is described in U.S.Pat.App.No. 20030195603A1. Coronary sinus catheter introducer system such as disclosed in U.S. Pat.No. 5488960 may be used to implant such leads. A bend near the distal end of the introducer enables placement of the end of the introducer into the coronary sinus opening and within the coronary sinus. Another coronary sinus guiding introducer utilized to introduce medical devices is disclosed in U.S.Pat.No. 6,656,166. Still another guiding catheter for delivery of intravascular devices to a patient's coronary sinus is disclosed in U.S.Pat.No. 6,021 ,340. However, significant difficulties have been experienced with this guiding procedure. Every patient has individual coronary sinus anatomy and X-ray imaging does not yield complete visualization of this anatomy. Therefore coronary sinus cannulation with this system may be a very long lasting procedure that does not always ensure the successful coronary sinus cannulation. The precise localization of the coronary sinus ostium is necessary to facilitate the coronary sinus cannulation and left heart lead implantation. In this scope U.S.Pat.No. 6,697,667 discloses one solution utilizing laser Doppler velocimetry detecting the characteristic coronary sinus blood flow pattern. An invasive, fluid velocity measuring wire guide particularly adapted for sub selective placement in the coronary arterial tree, which includes a Doppler mechanism for determining the blood flow velocity in the region of the distal end of the wire guide is disclosed in U.S.Pat.No. 4,920,967. Much more accurate system for localization of the coronary sinus may be achieved utilizing the ultrasonic catheter disclosed in U.S.Pat.No. 5,876,345. An ultrasonic catheter having at least two ultrasonic arrays is provided which has good near and far field resolution and provides an outline of the heart chamber, which assists in understanding and interpreting the images obtained, by the catheter. The major disadvantage of this system is the high price of a catheter. We propose a device and method of coronary sinus cannulation and left heart lead implantation that have not been disclosed in cited prior art. We solved the visualization problem for the implant tools, make use of easy soft tissue imaging and avoid the radiological hazard whereby keeping the system price low.

Disclosure of the Invention It is the principal object of this invention to provide a system for guiding the procedure for implantation of the cardiac pacing lead for ventricular resynchronization into the cardiac veins via the coronary sinus using ultrasonically marked catheter means for positive localization.

In accordance with the first aspect of the invention, the implant tools comprise an ultrasonic marking transducer having directional or omni directional ultrasonic sensitivity characteristics and mounted fixed in the vicinity of the tip of a catheter or an introducer being preshaped optimally for entering the coronary sinus,. The visualization of the tip is essential for ultrasonic guidance of said procedures with the either the catheter or introducer. The method for positive ultrasonic localization of a point on an indwelled device, e.g. the said introducer or the said catheter, consists of ultrasonic marking of the catheter and the use of a transponder to generate a visible mark on the ultrasound scanner screen. This means that the present method includes an imaging ultrasound scanner and the herewith described ultrasonically marked lead delivery catheter. One or more miniature piezoelectric marker transducers are mounted at the tip of the lead delivery catheter. The catheter may be preshaped in the way to make an easy implantation into the coronary sinus ostium. The catheter may also be a steerable in order to make the coronary sinus cannulation easier. The marker transducer's electrodes (fired-on silver or similar) are connected to the electrical conductors, which connect it along the catheter to an outside electrical connector at the proximal end of the lead delivery catheter. When the transducer on the catheter tip is in the scanning plane, it is energized by ultrasound beams from the transducer of the echoscope used for imaging of the procedure. Thus, generated high frequency pulses are conducted via built-in electrical conductors along the delivery introducer or the delivery catheter to the localization electronic circuit. The most straightforward electronic circuitry for the purpose of the localization is a transponder. The transponder localization system is a pulse train generator triggered by signal from the said marker transducer, whenever the marked part of the catheter is within the ultrasonic scanning plane. When an ultrasonic pulse reaches the marker transducer, the electrical pulse thus induced in it triggers a pulse generator whose output is taken back to the same marker transducer. The marker transducer now becomes an ultrasound transmitter producing a visible signal - mark, marking its position in the echographic image on the screen. Because the coronary sinus can be visualized by ultrasound echography in various cross sections, the said mark essentially facilitates the guiding of the procedure for positioning of the electrotherapy electrode into the left heart coronary tree.

Brief description of the drawings

Figure 1 discloses the flexible lead delivery catheter slid over the steerable ultrasonically marked catheter.

Figure 2 discloses another possible embodiment comprising ultrasonically marked delivery catheter with the bipolar pacing lead led through the said catheter. In the case that said lead is so called "over-the-wire" type, an optional ultrasonically marked guide wire is disclosed within lead's stylet channel.

Figure 3 illustrates the complete system used for ultrasonically marked procedure, comprising echocardiographic scanner with transthoracic scanning probe and a transponder.

Figure 4 illustrates the complete system used for ultrasonically marked procedure, comprising echocardiographic scanner with transesophageal scanning probe and a transponder.

Figure 5 illustrates the complete system used for ultrasonically marked procedure, comprising echocardiographic scanner with transthoracic scanning probe and two transponders, whereby ultrasonically marked guide wire is used.

Figure 6 illustrates a flow chart of the implanting procedure that utilizes the system disclosed in figure 1.

Figure 7 illustrates a flow chart of the implanting procedure that utilizes the system disclosed in figure 2.

Detailed Description of the Preferred Embodiments

Figure 1 discloses the left heart pacing lead delivery set that consists of a flexible delivery catheter 10 comprising a haemostatic valve 11 attached at its proximal end. Another, steering catheter 12 is inserted into the delivery catheter 10. Accordingly, delivery catheter 10 may be bended by steering catheter 12 thereby adjusting the shape of the catheter 10. The steering catheter may have shape and can be pre-formed in the way that it enables easy cannulation of the coronary sinus ostium. However, it also may be the steerable catheter comprising the mechanism (not shown) for it's bending in various directions. Such a steerable catheter is disclosed in this figure whereby proximal part of the steering mechanism is visible, being the steering handle 13 designed as it was disclosed in numerous prior art documents. The steering catheter comprises an ultrasonic transducer assembly 14 mounted fixed at its tip. It also comprises the electrical connection wires aimed for connection of the said transducer 14 with the external electronic circuits. Only proximal part of these two wires 15 and 16 are visible in this perspective drawing figure. In practice, the steering will change the orientation of the ultrasonic transducer 14 and consequently its sensitivity characteristics. Due to the fact that transducer 14 has omnidirectional radiation characteristics, the system is not very sensitive to the catheter movements and steering. An operator may easily track the catheter tip and the mark will not disappear due to bending. The goal of the procedure is placing a cardiac pacing lead into the coronary vein thereby positioning its active electrode in such a way as to enable left ventricular pacing. One of the standard procedures includes bringing a steering catheter, inserted through the lead delivery catheter, with its tip leaning against the ostium of the coronary sinus. Steering catheter may be pre-formed optimally for cannulation of the coronary sinus or may be a steerable catheter comprising the mechanism for bending in various shapes and directions. A delivery catheter is then introduced sliding over the said steering catheter's body and positioned within the coronary sinus. The said steering catheter is withdrawn, whereby leaving the delivery catheter in situ. Optionally, a venogram utilizing the balloon catheter and the x-ray diascopy may be done at this phase of implantation procedure. Expanded balloon prevents the coronary sinus flow and therefore X-ray contrast regimen may be injected into the coronary sinus in order to visualize the coronary veins on the X-ray equipment's screen. After the balloon catheter is withdrawn out of the delivery catheter, a cardiac pacing lead may be advanced through the delivery catheter and implanted into the selected coronary vein. There are different types of leads utilizing the guide wire for easier advancement into a distal segment of the coronary vein, such as "over-the-wire" or "side-wire." For implantation of such a lead, a guide wire may be inserted through the introducer into one of the selected left heart coronary veins. The pacing lead is introduced over the guide wire through the lead delivery catheter into the right atrium and further into the coronary sinus over the said guide wire and finally into the coronary vein. Once the pacing lead is in position, the introducer is withdrawn and the pacing lead stays within the left coronary vein. The guide wire is withdrawn too. The procedure must include visualization of the coronary sinus, localization of the pacing catheter tip, directing - steering the tip enabling its placement into the coronary sinus. This procedure is at the present done with X-ray guidance with considerable difficulty to cannulate the ostium of the coronary sinus. This leaves the operator with the problems of three dimensional real-time visualization of the coronary sinus and of the radiological hazard of such a procedure. The coronary sinus can well be visualized with ultrasound scanners, particularly using transesophageal probe. The steering catheter must be brought into the position at the coronary sinus ostium and than steered in such a way as to enter the coronary sinus along its axis. Thus one must have the possibility to guide its movement. A particular problem in ultrasonic imaging of flexible catheters indwelled into human body is the fact that these devices are not always entirely within the scanning plane, so that without special solution one can not know which part of the catheter is seen. This is a particularly hard problem if the catheter is within the heart so that it moves and thus only occasionally enters the scanning plane. This problem is particularly complicated if the angle at which one images the catheter is essentially different from 90° to the catheter axis in which case even the three dimensional imaging cannot help. The use of ultrasonically marked catheter overcomes this problem. In order to make the steering catheter tip visible within the 2-D echocardiographic image, the catheter wires 15 and 16 must be connected to the external transponder circuit. However, our procedure can visualize only the coronary sinus and cannot visualize the coronary veins. In the case when either a lead or a guide wire cannot advance from coronary sinus into the coronary vein, X-ray imaging will be still required, because a venogram would be mandatory to visualize the veins. It may be done by implantation of the balloon catheter whereby inflated balloon temporarily stops the blood outflow from the coronary sinus. Administration of a radiographic contrast into the coronary sinus when balloon is inflated, makes the distal left ventricular coronary veins visible within the x-ray image. Nevertheless, if the balloon catheter were ultrasonically marked, the radiographic imaging would be reduced only to the short period of an exposure during the contrast administration and the venogram image storage. Moreover, monitoring of the balloon inflation is easier utilizing the ultrasonic imaging. Nevertheless, the guide wire for over-the-wire lead insertion may also be ultrasonically marked. Though echocardiography cannot visualize coronary veins, position of the ultrasonically marked guide wire tip would be accurately displayed within the echocardiographic scanner's image. Further possible embodiment of our invention is disclosed in figure 2. In this system, the delivery catheter 20 also comprises a haemostatic valve 21 attached at its proximal end. Delivery catheter 20 is ultrasonically marked and therefore it comprises an ultrasonic transducer assembly 22 mounted fixed at its tip. Protruding out of its proximal part, catheter 20 comprises wires 23 and 24 that are electrically connected with the transducer 22. Left heart pacing lead 25 is disclosed to be inserted through the haemostatic valve 21 and delivery catheter 20. The lead 25 is bipolar and therefore it has an active electrode 26 at its tip and an indifferent electrode 27 proximally from the tip. Connector assembly is on its proximal end, as it is usual in the art, comprising central pin 28 connected with the electrode 26 and coaxial pin 29 connected with the electrode 27. Optionally, an ultrasonically marked guide wire 30 may also be used during the implant procedure. Assuming that the lead 25 is so called "over-the-wire" type, the guide wire 30 may be inserted through the stylet channel (not visible) of the lead 25. Guide wire 30 comprises an ultrasonic transducer assembly 31 at its tip and two wires 32 and 33 electrically connected to said transducer 31 protruding out of the proximal termination of the guide wire 30. The catheter 20 may have a mechanism (not shown) foe bending of its body in order to adapt its shape for easier cannulation of the coronary sinus. In practice, the bending will change the orientation of the ultrasonic transducer 22 and consequently its sensitivity characteristics. Due to the fact that transducer 22 has an omnidirectional characteristics, the system is not very sensitive to catheter movements and it's bending. An operator may easily track the catheter tip and the mark will not disappear due to the bending. The system for using implant tools from previous two figures, disclosed in figure 3, consists of an ultrasound scanner 41 that scans the body 100 interior with its probe 40. An area 42 is thus imaged on the scanner screen. The aim is to guide an implant tool 43 directly to the coronary sinus 44. The implant tool 43 can be a either a steerable catheter such as disclosed in figure 1 or a delivery catheter such as disclosed in figure 2. The implant tool 43 is electrically connected to a transponder 200. The transponder 200 is a pulse generator on demand. This pulse generator is triggered by the signal incoming from ultrasound transducer assembly 45 (actually either 14 of figure 1 , or 22 of figure 2). Ultrasound pulses incoming from the scanner probe 40 generate this signal at times when the said transducer assembly 45 is within the scanning area 42. The, thus triggered, pulse generator within transponder 200, generates a characteristic series of pulses - the signature, which is taken back to the said ultrasound transducer assembly. These pulses cause ultrasonic vibrations of the said transducer 45 so that it transmits a series of ultrasound pulses. This series of ultrasound pulses is seen in the image 101 of the organ of interest within the scanner image 52 as a visible and distinctive mark 201 that positively localizes the current position of the transducer assembly 45 in the vicinity of the coronary sinus 44 within the heart 102, within the patient's body 100. The ultrasound scanner 41 can operate with a transthoracic probe 40 as disclosed in figure 3 or with a transoesophageal probe 46 with an appropriate holder 47 as disclosed in figure 4. In both cases, it is essential to have the imaging area 42 covering the part of the heart were the coronary sinus 44 is located so that an image 111 of the coronary sinus, is seen in the ultrasound image 101 of the heart 102 in the image 52 on ultrasound scanner's screen 50. The implant tool proper can, in practice, not ideally and entirely be imaged and appears in the image as a moving interrupted structure 112 within the image 101 of the heart. The tip is therefore hard and often impossible to positively make out. However, when a transponder 200 is connected to the implant tool 43, the visible localization mark 201 appears on the scanner screen 50 irrespective of whether the implant tool 43 proper is seen on the screen or not. This mark 201 appears even if the implant tool 43 comes at right angle to the imaging plane 42 in which case it would appear as a single dot on the screen 50. Once the implant tool tip is positioned directly at the coronary sinus, the transponder 200 can be disconnected from the connecting device 210 and the implant tool 43 can then be used for its initial purpose, that is, as a step in implantation of resynchronization pacing lead into the blood vessels of the left heart. Operating frequency spectrum of the scanner probe 40 and the marker transducer assembly 45 must significantly overlap, that is, they must be able to transmit and receive ultrasound generated by each other. The sensitivity of the electronic circuitry 41 and 200 must be adapted to this ultrasonic communication between the two transducer assemblies 45 and 40. Figure 5 illustrates the system for procedure when using the ultrasonically marked guide wire such as 30 of figure 2. The switchbox 210 is used to connect the wires of the ultrasonic assemblies of both, delivery tool and guide wire. One transducer is connected to the first transponder 200 and another transducer is connected to the second transponder. The guide wire cannot be visualized on the echocardiographic screen. However, if it were implanted with its tip 31 within the coronary vein, an additional mark 202 would appear on the 2-D echocardiographic image pointing to the guide wire tip. Illustrated case may only appear if the scanning plane 42 intersects both ultrasonic transducers - the one of the delivery tool and the one of the guide wire. Figure 6 is a flowchart that describes a method of use of our invention utilizing delivery system such as disclosed in figure 1. Echocardiographic examination of the patient may be done in order to adjust the scanner to obtain the best imaging of the patient. The transponder may be prepared at the same time (600) and optionally even checked with an non-sterile catheter in an ultrasonic phantom. Subclavian vein must be punctured in order to introduce the subclavian introducer within the vein (601) in order to allow the implantation 602 of the steerable catheter 12. The steerable catheter 12 is designed to have several degrees of freedom to be bent having different curves, as it is known in the art. It comprises a delivery catheter 10 slid over its body. The steerable catheter is ultrasonically marked by an ultrasonic transducer 14 mounted fixed at its tip. After the steerable catheter 12 comprising a delivery catheter 10 has been inserted within the subclavian vein, the subclavian introducer may be extracted (603) and disposed. The image of the right atrium of the patient has to be shown (604) within the image of the echocardiographic scanner. Connector assembly (15 & 16) at the proximal end of the ultrasonically marked steerable catheter 12 has to be connected (605) to the transponder by a sterile patient cable in order to connect the ultrasonic transducer 14 to the transponder. By spatial adjustment of the echocardiographic probe, scanning plane's angle is varied until a visible mark appears on the echocardiographic scanner image 52. By imaging both, coronary sinus ostium and the steerable catheter's tip, the steerable catheter may be introduced within the coronary sinus ostium (606). The steerable catheter may be advanced (607) within the coronary sinus. The advancement has to be echocardiographically monitored whereby coronary sinus and tip of the catheter may be visualized (608) within the scanner image. When satisfactory position of catheter's tip has been reached within the coronary sinus, the implanting physician may decide to stop (609) further advancement of the catheter. Delivery catheter may be slid (610) distally over the delivery catheter deeply into the coronary sinus. As the delivery catheter is slid over the ultrasonic marker transducer, the mark disappears (611) from the echocardiographic image. Delivery catheter may now be advanced (612) to its final position and the steerable ultrasonically marked catheter may be extracted (613). Standard procedure of contrast X-ray imaging (614) utilizing a balloon catheter may be done in order to visualize distal coronary veins. The pacing lead may now be inserted (615) through delivery catheter into the coronary sinus and with its tip implanted (616) within a coronary vein. Delivery catheter may be extracted (617) at this step.

Figure 7 is a flowchart that describes a further method of use of our invention utilizing delivery system such as disclosed in figure 2. Echocardiographic examination of the patient may be done in order to adjust the scanner to obtain the best imaging of the patient. The first transponder may be prepared at the same time (700) and optionally even checked with an non-sterile catheter in an ultrasonic phantom. Subclavian vein must be punctured in order to introduce the subclavian introducer within the vein (701) in order to allow the insertion 702 of the delivery catheter. The delivery catheter is bent to have an optimal curve for cannulation of the coronary sinus ostium. It is ultrasonically marked by an ultrasonic transducer mounted fixed at its tip. After the delivery catheter has been inserted (702) into the right atrium, the subclavian introducer may be extracted (703) and disposed. The image of the right atrium of the patient has to be shown (704) on display of the echocardiographic scanner. Connector assembly at the proximal end of the ultrasonically marked delivery catheter has to be connected (705) to the first transponder by a sterile patient cable in order to connect the catheter's ultrasonic transducer to the first transponder. By spatial adjustment of the echocardiographic probe, scanning plane's angle is changed until a visible mark appears on the echocardiographic scanner image. By imaging both, coronary sinus ostium and the catheter's tip, the ultrasonically marked delivery catheter may be introduced within the coronary sinus ostium (706). The delivery catheter may be advanced (707) within the coronary sinus. The advancement has to be echocardiographically monitored whereby coronary sinus and tip of the catheter may be visualized (708) within the scanner image. Standard procedure of contrast X-ray imaging utilizing a balloon catheter may be done (not shown in the flow chart) in order to visualize distal coronary veins. The second transponder may be switched on (709) and the connector assembly at the proximal end of an ultrasonically marked wire may be now connected (710) in order to connect the wire's ultrasonic transducer to the transponder. The ultrasonically marked wire may now be inserted (711) through delivery catheter into the coronary sinus. The pacing lead may now be inserted 712 over the wire through delivery catheter into the coronary sinus. The wire tip position is continuously monitored (714) by visualizing the ultrasonic marker generated by the second transponder while advancing the wire into the coronary vein. When satisfactory position of wire's tip has been reached within the coronary vein, the implanting physician may decide to stop (715) further advancement of the wire. The pacing lead may now be advanced (716) over the wire into the coronary vein. As the pacing lead is slid over the ultrasonic marker transducer of the wire, the mark generated by second transponder disappears from the echocardiographic image, which may be the sign to stop (717) advancing the lead. Wire may be extracted (718) at this step and delivery catheter may be extracted (719) after that.

Claims

1. A left heart pacing lead delivery system, comprising an echocardiographic scanner, an ultrasonically marked pacing lead delivery means and transponder electronic circuits, whereby said delivery means is suitable to make the tip visible within the echocardiographic image of the right atrium and coronary sinus whenever connected to said transponder circuits and the scanning plane of said echocardiographic scanner intersects the tip of said delivery means.

2. A left heart pacing lead delivery system of claim 1 , wherein said delivery means is an elongated flexible catheter comprising an ultrasonic transducer means mounted fixed at its tip whereby its said tip is adapted to be made visible as a mark within the echocardiographic image of the right atrium and coronary sinus whenever said transducer means is connected to said transponder circuits and the scanning plane of said echocardiographic scanner intersects said transducer means.

3. A left heart pacing lead delivery system of claim 1 , wherein said delivery means is an elongated flexible catheter having a steering catheter inserted within its hollow body, said steering catheter comprising an ultrasonic transducer means mounted fixed at its tip whereby said tip of said steering catheter is adapted to being made visible as a mark within the echocardiographic image of the right atrium and coronary sinus whenever is said transducer means connected to said transponder circuits and the scanning plane of said echocardiographic scanner intersects said transducer means and said tip of the steering catheter protrudes out of the body of said delivery catheter.

4. A left heart lead delivery system of claim 1 , wherein said delivery means includes a guiding wire comprising an ultrasonic transducer means mounted fixed at its tip whereby said pacing lead comprises a hollow channel and may be inserted within the coronary sinus and great cardiac vein over said guiding wire while said wire tip is adapted to be made visible as a mark within the echocardiographic image whenever said transducer means is connected to said transponder circuits and the scanning plane of said echocardiographic scanner intersects said transducer means and said tip of guiding wire protrudes out of the body of said pacing lead.

5. A left heart lead delivery system of claims 2 and 3 wherein said catheter comprises mechanism for bending of its body thereby adapting the shape to enter the ostium of coronary sinus whereby said bending changes the spatial orientation of said transducer thereby changing spatial orientation of the directivity characteristics of said transducer.

6. A left heart lead delivery system of claims 2 and 4, wherein said transponder electronic circuits comprise two transponders whereby said ultrasonic transducer means mounted on the said catheter is connected to the first of said transponders and said ultrasonic transducer means mounted on the said wire is connected to the second of said transponders.

7. A left heart lead delivery system of claims 3 and 4, wherein said transponder electronic circuits comprise two transponders whereby said ultrasonic transducer means mounted on the said steering catheter is connected to the first of said transponders and said ultrasonic transducer means mounted on the said wire is connected to the second of said transponders.

8. A left heart lead delivery system of claim 6, comprising means for making said first transducer of said catheter means and said second transducer of said wire being visible within the image of said echographic scanner means as two separate marks whenever said wire protrudes out of the body of said pacing lead and whenever the scanning plane area of said echographic scanner means intersects both said ultrasonic transducers.

9. A left heart lead delivery system of claim 7, comprising means for making said first transducer of said steering catheter means and said second transducer of said wire being visible within the image of said echographic scanner means as two separate marks whenever said wire protrudes out of the body of said pacing lead and said steering catheter protrudes out of the body of said delivery catheter, and whenever the scanning plane area of said echographic scanner means intersects both said ultrasonic transducers.

10. A method of implanting an intravenous cardiac pacing lead within a cardiac vein via the coronary sinus of the human heart, said method comprising the steps of: -providing an echocardiographic scanner, an ultrasonically marked delivery catheter, a transponder electronic circuits and a cardiac pacing lead adapted to be implanted into a coronary vein; -introducing the said delivery catheter into the coronary sinus under echocardiographic guidance whereby tip of said delivery catheter is visible as a mark within the echocardiographic image; -inserting the said lead into the lumen of said delivery catheter; -implanting the lead into the coronary vein; -extracting the said delivery catheter.

11. The method of claim 10 wherein providing step includes providing an elongated flexible delivery catheter comprising a first ultrasonic transducer means mounted fixed at its tip whereby said tip is visible as a mark within the echocardiographic image of the right atrium and coronary sinus whenever said first transducer means is connected to said transponder circuits and the scanning plane of said echocardiographic scanner intersects said first transducer means.

12. The method of claims 10 wherein said introducing step includes connection of said first transducer to the said transponder adapted to generating a series of electrical pulses when triggered by a signal from the said first transducer means its output being connected to the said first transducer.

13. The method of claim 12, wherein said introducing step includes that operator shows the image of the coronary sinus on the echocardiographic scanner's screen and by manipulating the probe of said echocardiographic scanner and by moving the said delivery catheter produces the mark within the said image pointing to the position of the said first ultrasonic transducer means mounted on said delivery catheter thereby guiding the implantation of said delivery catheter through the ostium and within the cavity of the said coronary sinus.

14. The method of claim 10, wherein said inserting step includes insertion of the said pacing lead into the lumen of said delivery catheter, whereby position of the delivery catheter may be monitored by means of observing the said mark within the echocardiographic image.

15. The method of claim 10, wherein said implanting step includes advancing the lead through said delivery catheter in order to position its tip within a cardiac vein for left ventricular pacing whereby position of the delivery catheter may be monitored by means of observing the said mark within the echocardiographic image.

16. The method of claim 10, wherein said extracting step includes extraction of said delivery catheter while leaving the said pacing lead in situ and whereby position of the delivery catheter may be monitored by means of observing the said mark within the echocardiographic image.

17. A method of implanting an intravenous cardiac pacing lead within a cardiac vein via the coronary sinus of the human heart, said method comprising the steps of: -providing an echocardiographic scanner, an ultrasonically marked steering catheter, a lead delivery catheter, a transponder electronic circuits and a cardiac pacing lead adapted to be implanted into a coronary vein; -introducing the said steering catheter together with said delivery catheter into the coronary sinus under echocardiographic guidance whereby tip of steering catheter is visible as a mark within the echocardiographic image; -inserting the said lead into the lumen of said delivery system; -implanting the lead into the coronary vein; -extracting the said delivery catheter.

18. The method of claim 17 wherein providing step includes providing an elongated flexible delivery catheter having a steering catheter inserted within its hollow body, said steering catheter comprising a second ultrasonic transducer means mounted fixed at its tip whereby said tip of said steering catheter is adapted to be made visible as a mark within the echocardiographic image of the right atrium and coronary sinus whenever is said second transducer means connected to said transponder circuits and the scanning plane of said echocardiographic scanner intersects said second transducer means and said tip of the steering catheter protrudes out of the body of said delivery catheter.

19. The method of claim 17 wherein said introducing step includes connection of said second transducer to the said transponder adapted to generating a series of electrical pulses when triggered by a signal from the said second transducer means its output being connected to the said second transducer.

20. The method of claim 17, wherein said introducing step includes that operator shows the image of the coronary sinus on the echocardiographic scanner's image and by manipulating the probe of said echocardiographic scanner and by steering of the said steering catheter produces the mark within the said image pointing to the position of the said second ultrasonic transducer means mounted on said steering catheter thereby monitoring the implantation of said steering catheter together with said delivery catheter through the ostium and within the cavity of said coronary sinus.

21. The method of claim 20, whereby said introducing step includes sliding the said delivery catheter over the body of said steering catheter and advancing of said delivery catheter into the said coronary sinus whereby said mark pointing to the second transducer's position disappears when said delivery catheter is slid over the said second transducer.

22. The method of claim 17, whereby said inserting step includes extraction of said steering catheter out of the lumen of said delivery catheter whereby position of the steering catheter may be monitored by means of observing the said mark within the echocardiographic image, and insertion of said cardiac pacing lead into the lumen of said delivery catheter.

23. The method of claim 17, whereby said implanting step includes advancing the lead through said delivery catheter in order to position its tip within a cardiac vein for left ventricular pacing.

24. The method of claim 17, wherein said extracting step includes extraction of said delivery catheter while leaving the said pacing lead in situ.

25. A method of implanting an intravenous cardiac pacing lead within a cardiac vein via the coronary sinus of the human heart, said method comprising the steps of: -providing an echocardiographic scanner, an ultrasonically marked delivery catheter, an ultrasonically marked guiding wire, a transponder electronic circuits and a cardiac pacing lead adapted to be implanted into a coronary vein and adapted to be implanted over the said guiding wire, -introducing the said delivery catheter into the coronary sinus under echocardiographic guidance whereby tip of said delivery catheter is visible as a mark within the echocardiographic image; -inserting the said lead together with said guiding wire into the lumen of said delivery catheter whereby tip of said guiding wire is visible as a mark within the echocardiographic image; -implanting the lead into the coronary vein; -extracting the said delivery catheter.

26. The method of claim 25 wherein providing step includes providing a guiding wire adapted to be inserted within a coronary vein and comprising a third ultrasonic transducer means mounted fixed at its tip whereby said pacing lead comprises a hollow channel and may be inserted within the coronary sinus and great cardiac vein over said guiding wire while said wire tip is adapted to be made visible as a mark within the echocardiographic image whenever said third transducer means is connected to said transponder circuits and the scanning plane of said echocardiographic scanner intersects said third transducer means and said tip of guiding wire protrudes out of the body of said pacing lead.

27. The method of claim 25 wherein said introducing step includes connection of said third transducer to said transponder circuits adapted to generating a series of electrical pulses when triggered by a signal from the said third transducer means its output being connected to the said third transducer.

28. The method of claim 25, wherein implanting step includes insertion of the said guide wire under control of echocardiographic imaging into the coronary vein whereby tip of the said wire is visible as a mark within the echocardiographic image.

29. The method of claim 28, whereby implanting step includes implantation of said cardiac pacing lead over the said wire and whereby said mark disappears when lead is advanced and slid over said ultrasonic transducer.

30. The method of claim 29, whereby implanting step includes extraction of said guiding wire under control of echocardiographic imaging.

31. The method of claim 25, wherein said extracting step includes extraction of said delivery catheter while leaving the said pacing lead in situ and whereby position of the delivery catheter may be monitored by means of observing the said mark within the echocardiographic image.