Mapping and ablation catheter with multiple loop segments

Abstract

A mapping and ablation catheter (1) is presented. The mapping and ablation catheter comprises an elongated catheter shaft (10) and an ablation portion (11) arranged at a distal end (10-1) of the catheter shaft (10), wherein: the ablation portion (11) comprises a plurality of ring segments (111, 112, 113, 114); at least one first ring segment (111) of the plurality of ring segments (111, 112, 113, 114) has one or more ablation electrodes (110) configured to deliver energy to vascular tissue; the ring segments (111, 112, 113, 114) together form a three-dimensional helix; and the respective diameters of the ring segments (111, 112, 113, 114) are such that when the three-dimensional helix is ​​compressed, each ring segment (111, 112, 113, 114) rests on an adjacent ring segment (111, 112, 113, 114). The plurality of ring segments (111, 112, 113, 114) includes a stabilizer ring segment (114) which does not have any electrodes, wherein the stabilizer ring segment (114) is the most proximal ring segment of the plurality of ring segments (111, 112, 113, 114).

Description

Technical Field

[0001] The present invention relates to embodiments of mapping and ablation catheters. In particular, the present invention relates to embodiments of mapping and ablation catheters that can be used for pulmonary vein isolation (PVI), such as multi-electrode irrigated radio frequency (RF) ablation catheters. Background Art

[0002] As is well known, in the treatment of patients with atrial fibrillation (AF), ablation catheters are used for PVI procedures. In this procedure, the pulmonary veins (PVs) are electrically isolated from the left atrium by creating contiguous annular ablation lesions around the pulmonary vein orifices (PVOs). Thus, irregular atrial contractions can be avoided by preventing unwanted interfering electrical signals generated within the PVs from propagating into the left atrium.

[0003] There are several types of AF ablation catheters available, including single point tip electrode catheters, circular multi-electrode ring catheters, and balloon-based ablation catheters using different energy sources. Examples include cryoballoon catheters as described in documents US 6,666,853 B2 and US 7,101,368 B2; laser balloon catheters as described in documents US 8,540,704 B2 and US 9,861,437 B2; RF balloon catheters as described in US 9,352,134 B2, electrode array catheters as described in document US 8,641,704 B2; and irrigated multi-electrode catheters as described in US 9,717,559 B2.

[0004] EP 3 023 069 A1 relates to a multi-electrode perfused lumen catheter with a soft distal tip for mapping and ablating tubular regions. Particularly disclosed is a catheter tip with a soft distal ring and a more rigid proximal ring, the proximal ring having ablation ring electrodes and the distal ring having ring electrodes for sensing electrical potentials.

[0005] US 2001007070 and WO 02 / 089687 A1 each describe a catheter with a helical distal portion and an ablation portion formed along the helix.

[0006] Known ablation catheters have several disadvantages.

[0007] For example, if a single irrigating tip is used to perform point-by-point ablation, this method is slow and tedious and requires a skilled electrophysiologist (EP) physician. In addition, in the case of using a single irrigating tip, the ablation lesion spacing is quite problematic and may require a redo operation.

[0008] Disposable balloon catheters can be quite inflexible and can sometimes slip out of the PVO. In addition, such catheters require a relatively large French-sized delivery sheath.

[0009] Multiple electrodes on a single ring structure can present tissue contact challenges because a single ring cannot accommodate a variety of PVO shapes and sizes due to inherent variability in human anatomy between individuals. Summary of the invention

[0010] It is an object of the present invention to provide an improved ablation catheter for PVI.

[0011] This is achieved by a catheter, in particular an ablation catheter, comprising an elongated catheter shaft and an ablation portion arranged at the distal end of the catheter shaft, wherein: the ablation portion comprises a plurality of ring segments (i.e., at least two ring segments); at least one first ring segment of the plurality of ring segments has one or more ablation electrodes, the one or more ablation electrodes being configured to deliver energy to vascular tissue; the ring segments together form a three-dimensional helix; and the respective diameters of the ring segments are such that when the three-dimensional helix is ​​compressed, each ring segment rests on an adjacent ring segment. In particular, it can be arranged that when the three-dimensional helix is ​​compressed, each ring segment can rest on an adjacent ring segment along its entire circumference.

[0012] The ablation catheter may be configured primarily for ablation in PVO as well as other atrial regions of the human heart.

[0013] The three-dimensional spiral formed by a plurality of ring segments can be a graduation of a spiral with a varying radius, wherein the ablation electrode can be arranged circumferentially on a first ring segment. Thus, for example, the ablation portion can have a substantially tornado-shaped tip formed by ring segments, which will also be referred to hereinafter as a spiral ring segment.

[0014] Compared to a single ring type ablation catheter, due to the tornado-shaped or spiral structure and the flexibility of the ring segments, the ablation portion can better conform to different shapes of the PVO. Therefore, better tissue contact can be achieved, which can lead to more targeted energy delivery and potentially shorter ablation times to generate adjacent lesions. In other words, the proposed ablation catheter may be particularly suitable for high-power / short-duration ablation approaches, which have become generally very attractive to EP physicians in recent years.

[0015] Furthermore, the plurality of ring segments may include a stabilizer ring segment, which does not have any electrodes, wherein the stabilizer ring segment is the most proximal ring segment of the plurality of ring segments. The stabilizer ring segment may also be referred to as a rear ring segment.

[0016] The posterior ring segment can be configured to add lateral stability and structural support to the distal ring assembly when engaged in the pulmonary vein so that the ablation electrode can act on the PVO or other atrial regions of the heart during the course of an ablation procedure. Since the stabilizer ring segment does not have an ablation electrode, its shape and arrangement can be optimized for stabilization function, particularly during a PVI procedure when the ablation portion is engaged with the PV near the PVO.

[0017] For example, in one embodiment, the diameter of the stabilizer ring segment is smaller than the diameter of the adjacent ring segment, ie the diameter of the adjacent ring segment arranged away from the stabilizer ring segment. As a result, the ablation portion as a whole (including the stabilizer ring segment) can have a barrel-shaped profile or at least a semi-barrel-shaped profile.

[0018] In one embodiment, the second ring segment of the plurality of ring segments further comprises a plurality of ablation electrodes. For example, the second ring segment and the first ring segment, each comprising a plurality of ablation electrodes, may be adjacent ring segments. In particular, the ablation electrodes of the second ring segment may be arranged in a staggered manner relative to the ablation electrodes of the first ring segment.

[0019] Where current PVI procedures are more targeted at the PV antrum and some non-PV AF trigger points in the atrium, two spiral ablation ring segments, each with an ablation electrode, allow for a wider or broader ablation zone, somewhat comparable to the effectiveness of a balloon ablation catheter.

[0020] To achieve this without adding too many additional ablation electrodes (which may make it more difficult to create adjacent lesions), it may be advantageous to use relatively long ablation electrodes. For example, the length of the ablation electrodes may be equal to or greater than 4.0 mm.

[0021] In a preferred variant, the ablation electrode may be sleeve-shaped or tubular. For example, the diameter of such a sleeve-shaped or tubular ablation electrode may be equal to or greater than 2.0 mm. Further, as described above, the length of the sleeve-shaped or tubular ablation electrode may be equal to or greater than 4.0 mm.

[0022] As a suitable material, the ablation electrode may include, for example, at least one of gold and a platinum / iridium alloy.

[0023] According to one embodiment, the ablation catheter is configured to deliver electrical RF signals to vascular tissue via ablation electrodes. In other words, the ablation catheter can be configured to perform RF ablation. Currently, RF is still a more preferred energy than other energies due to its long history of use in PVI.

[0024] For example, an ablation catheter may be configured for connection to a multi-channel RF generator configured to deliver RF energy and transmit electrographic signals for PVI procedures in AF patients.

[0025] In other embodiments, the proposed helical shape structure of the ablation portion can be applied to ablation catheters that utilize energy sources other than RF, such as electroporation, pulsed field ablation, or cryoablation.

[0026] Preferably, the ablation electrode is an irrigated ablation electrode, such as a saline irrigated ablation electrode. To this end, the ablation electrode may have an outlet and / or a plurality of micropores or pores, and to assist the delivery of the irrigated liquid.

[0027] Thus, the ablation electrode is cooled by the irrigation liquid during operation.In addition, the electrically conductive irrigation liquid can support the delivery of electrical energy (eg RF signals) to the vascular tissue, thereby allowing the targeted creation of adjacent lesions.

[0028] For example, when the ablation electrodes are sleeve-shaped or tubular, the tubular wall of each ablation electrode may include a spiral irrigation opening or cutout. Thus, the flux of irrigation can be evenly distributed along the length of the ablation electrode, particularly for improved cooling. An additional advantage of electrodes with longer lengths (4.0 mm or longer) having a spiral outlet or cutout is that the electrode becomes more flexible than a solid ring electrode and is therefore more compliant with tissue contact at the PVO.

[0029] For example, the lumens provided in the ring segments for saline irrigation delivery may have various durometers and cross-sectional shapes to evenly deliver saline irrigation to all ablation electrodes.

[0030] Additionally, some or all ablation electrodes may include one or more temperature sensors to monitor electrode temperature and provide feedback to, for example, a multi-channel RF generator for controlling ablation parameters such as power and irrigation flow.

[0031] It is also within the scope of the present invention that the ablation portion may include multiple mapping electrodes configured to receive electrical signals from vascular tissue. This may enable mapping and ablation for PVI with a single ablation catheter, as well as ablation of some non-PV triggers for AF patients.

[0032] For example, in one embodiment, a third ring segment of the plurality of ring segments may have a plurality of mapping electrodes. Additionally or alternatively, in addition to the ablation electrodes, the mapping electrodes may also be arranged in the first ring segment and / or, where applicable, on the second ring segment described above. The plurality of mapping electrodes may also be integrated at the distal end of the plurality of ablation electrodes, or in the middle of two ablation electrodes. In addition, the third ring segment may include ablation electrodes as an addition or alternative to the mapping electrodes.

[0033] In an advantageous embodiment, the ablation portion, and in particular the ring segment, comprises a shape memory material. Preferably, the shape memory material is a superelastic material (e.g. a superelastic alloy), which means that the material is elastic and has shape memory properties. For example, Nitinol is a biocompatible superelastic alloy suitable for this purpose.

[0034] In a variation, the ablation portion, and in particular the ring segment, may include an internal support element, such as an internal support wire, having such shape memory or superelastic properties. For example, the internal support wire may be a nitinol wire. The shape memory support wire may have various stiffnesses and cross-sectional shapes.

[0035] In one embodiment, the ablation catheter further comprises a steerable delivery sheath. Therefore, in operation, the position of the ablation portion can be easily adjusted at the target vascular tissue until the contact of each ablation electrode is satisfied.

[0036] Advantageously, in some embodiments, the proposed helical shape configuration of the ablation portion may require a smaller sized transseptal sheath than those used with existing balloon ablation catheters.

[0037] In another embodiment, the catheter, particularly an ablation catheter, further includes at least one or two pull wires that come from a handle in the proximal end of the catheter and are attached to the distal end segment of the main shaft to enable the distal ring segment to be deflected unidirectionally or bidirectionally. Additional pull wires may be included to compress or adjust the diameter of the ring segment. These catheter features allow further adjustment capabilities to improve the alignment of the ring segment within the PVO.

[0038] The catheters disclosed herein with multiple ablation electrode configurations, particularly ablation catheters, address the above-mentioned drawbacks of available approaches. In addition, the helical structure of the ablation portion, preferably in combination with an irrigated flexible ablation electrode, addresses the challenge of tissue contact.

[0039] Unless explicitly stated otherwise, all aspects and features of the embodiments described above and below may be combined with one another. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The various features and advantages of the present invention may be more readily understood with reference to the following detailed description and the embodiments illustrated in the accompanying drawings.

[0041] Figure 1 Schematically and exemplarily illustrates a distal portion of an ablation catheter according to one or more embodiments;

[0042] Figure 2 The delivery path of an ablation catheter to the pulmonary vein ostium of a human heart is schematically and exemplarily shown;

[0043] Figure 3 The distal end portion of the ablation catheter located on the ostium of the pulmonary vein is schematically and exemplarily shown;

[0044] Figure 4 Schematically and exemplarily illustrates a distal portion of an ablation catheter including an irrigated ablation electrode according to one or more embodiments;

[0045] Figure 5 It shows that Figure 3 and Figure 4 a cross-sectional view of the distal portion shown; and

[0046] Figure 6 A sleeve-shaped ablation electrode of an ablation catheter according to one or more embodiments is schematically and exemplarily shown. DETAILED DESCRIPTION

[0047] Figure 1 The distal portion of an ablation catheter 1 according to one or more embodiments is schematically and exemplarily shown. The catheter 1 has an elongated circular catheter shaft 10 which may include a handle (not shown) at the proximal end to manipulate the deflection of the shown distal end 10-1 of the catheter shaft.

[0048] The ablation portion 11 is disposed at the illustrated distal end 10 - 1 of the catheter shaft 10 , and the ablation portion 11 includes a plurality of compressible ring segments 111 , 112 , 113 , 114 .

[0049] Each of the first ring segment 111 and the adjacent second ring segment 112 has a plurality of ablation electrodes 110, which are configured to deliver energy to the vascular tissue. In particular, the ablation catheter 1 can be configured to deliver electrical RF signals to the vascular tissue via the ablation electrodes 110. For example, the ablation electrodes 110 can be composed of or include gold and / or a platinum / iridium alloy.

[0050] exist Figure 1 In the exemplary embodiment shown, the ablation electrodes 110 of the second ring segment 112 are arranged in a staggered manner relative to the ablation electrodes 110 of the first ring segment 111 .

[0051] In addition, a third ring segment 113 is provided, wherein the third ring segment 113 is the most distal ring segment 113 among the plurality of ring segments 111, 112, 113, 114. According to the present exemplary embodiment, the third ring segment 113 can also be referred to as the front ring segment 113. The third ring segment has a plurality of mapping electrodes 115, which are configured to receive electrical signals from vascular tissue.

[0052] Furthermore, the plurality of ring segments 111 , 112 , 113 , 114 include a stabilizer ring segment 114 , which does not have any electrodes. The stabilizer ring segment 114 is the most proximal ring segment of the plurality of ring segments 111 , 112 , 113 , 114 and may therefore also be referred to as a rear ring segment 114 .

[0053] The ring segments 111, 112, 113, 114 together form a (compressible) three-dimensional spiral characterized by a tornado-shaped tip portion. It should be noted that the diameter of each ring segment 111, 112, 113, 114 is such that when the three-dimensional spiral is compressed, each ring segment 111, 112, 113, 114 rests on the adjacent ring segment 111, 112, 113, 114 along its entire circumference. This Figure 3 is more clearly shown in Figure 3 is further explained in the following description.

[0054] like Figure 1 and Figure 3 As can be seen in the figures, the diameter of the stabilizer ring segment 114 is smaller than the diameter of the adjacent first ring segment 111. Combined with the cyclone-shaped arrangement of the first, second and third rings 111, 112, 113 (which have decreasing diameters in the proximal to distal direction), this results in the ablation portion having a substantially barrel-shaped profile.

[0055] The ring segments 111, 112, 113, 114 may include a shape memory material, for example, in the form of an internal structural support wire (not shown) having shape memory properties. For example, a nitinol wire may be provided as the internal structural support wire. In particular, the ring segments 111, 112, 113, 114 may have superelastic properties.

[0056] Thus, the ablation portion 11 may be configured from an offset configuration (e.g., Figure 1 The ablation portion 11 may be constrained to a substantially elongated shape for the purpose of being delivered to a target area in a human body by a (fixed or steerable) delivery sheath 12 (also referred to as a guide sheath 12). At the target location, upon leaving the distal end of the guide sheath 12, the ablation portion 11 may then be re-curled to its original (biased) shape.

[0057] Figure 2The delivery path of an ablation catheter 1 leading to a pulmonary vein ostium PVO in a human heart is schematically and exemplarily shown. For the sake of introduction, the inferior vena cava IVC, right atrium RA, right ventricle RV, left atrium LA, left ventricle LV and pulmonary veins PV are shown, each with a pulmonary vein ostium PVO. The large white arrows indicate the delivery path through the inferior vena cava IVC, right atrium RA, through the septum wall SW, and left atrium LA, ultimately leading to the region of the pulmonary vein ostium PVO.

[0058] Figure 3 The distal portion of the ablation catheter 1 located on the pulmonary vein ostium PVO is schematically and exemplarily shown. As shown, the spiral-shaped ablation portion 11 can be placed in the sinus portion of the pulmonary vein PV to achieve pulmonary vein isolation PVI ablation. The distal end 10-1 of the catheter shaft 10 and / or the steerable sheath 12 can be deflected to ensure that the ablation portion 11 is correctly aligned with the opening angle of the pulmonary vein ostium PVO. For example, the positioning of the ablation portion 11 can be adjusted until contact with each ablation electrode 110 and / or mapping electrode 115 is met. If necessary, the steerable sheath 12 can be used to gently push the ablation portion 11 to maintain stability.

[0059] Figure 3 The ablation portion 11 is shown in a compressed state, wherein each ring segment 111, 112, 113, 114 rests on an adjacent ring segment 111, 112, 113, 114 along its entire circumference. In particular, the rear ring segment 114 provides lateral stability and structural support to the distal ring assembly 111, 112, 113, 114.

[0060] Once the ablation portion is in place, ablation can be performed by the ablation electrodes 110 in a monopolar manner or in a bipolar mode, either simultaneously, sequentially, or individually within the same ring 111, 112 or across the rings 111, 112 between adjacent ablation electrodes 110. During ablation, the physician can observe a decrease in PV potential with the mapping electrodes 115 and / or the ablation electrodes 110.

[0061] Figure 4 The distal end portion of the ablation catheter 1 including the irrigated ablation electrode 110 according to one or more embodiments is schematically and exemplarily shown; in particular, Figure 4 Irrigation of an irrigation fluid, such as a saline irrigation fluid, through an irrigation outlet and / or a plurality of micropores or apertures provided in the ablation electrode 110 is shown.

[0062] Figure 5 Shows Figure 3 A cross-sectional view of the distal end portion is shown, wherein in particular an overlap of 10-70% of the tube or French diameter from one ring to an adjacent ring is shown. Figure 3As shown, each ring segment 111, 112, 113, 114 rests on an adjacent ring along its entire circumference, with ring segment 114 (referred to as the rear ring segment) overlapping the adjacent tube diameter of ring 111 by 10-70%. Ring segment 114 has a ring diameter that is smaller than the ring diameter of ring segment 111. The same can be said of ring segment 112, which has a smaller ring diameter than the adjacent ring segment 111. Likewise, ring segment 113 is smaller in size than ring segment 112.

[0063] Figure 6 The ablation electrode 110 of the ablation catheter 1 according to one or more embodiments is schematically and exemplarily shown. The ablation electrode 110 is substantially sleeve-shaped or tubular.

[0064] The diameter D of the sleeve-shaped or tubular ablation electrode 110 may be equal to or greater than 2.0 mm. The length L of the sleeve-shaped or tubular ablation electrode 110 may be equal to or greater than 4.0 mm.

[0065] The tubular wall of the ablation electrode 110 includes a spiral irrigating outlet or cutout 1101. Thus, the flux of irrigation is evenly distributed along the length L of the ablation electrode 110, with the plurality of micro-protrusion cutouts 1102 acting as outlet spacers.

[0066] Reference numerals list

[0067] 1 Ablation catheter

[0068] 10 Catheter shaft

[0069] 10-1 Distal end of the catheter shaft

[0070] 11 Ablation Section

[0071] 110 Ablation Electrode

[0072] 1101 Infusion outlet

[0073] 111 First Ring Section

[0074] 112 Second Ring

[0075] 113 Third Ring

[0076] 114 Stabilizer ring segment

[0077] 115 Mapping Electrode

[0078] 12 Delivery sheath

[0079] D Diameter of the ablation electrode

[0080] IVC inferior vena cava

[0081] L is the length of the ablation electrode.

[0082] LA left atrium

[0083] LV Left ventricle

[0084] PV Pulmonary vein

[0085] PVO Pulmonary vein orifice

[0086] RA Right atrium

[0087] RV Right ventricle

[0088] SW next door.

Claims

1. An ablation catheter (1), comprising an elongated catheter shaft (10) and an ablation portion (11) arranged at a distal end (10-1) of the catheter shaft (10), wherein: - the ablation portion (11) comprises a plurality of ring segments (111, 112, 113, 114); - at least one first ring segment (111) of the plurality of ring segments (111, 112, 113, 114) has one or more ablation electrodes (110), wherein the one or more ablation electrodes (110) are configured to deliver energy to vascular tissue; - the ring segments (111, 112, 113, 114) together form a three-dimensional helix; - the respective diameters of the ring segments (111, 112, 113, 114) are such that each ring segment (111, 112, 113, 114) rests on an adjacent ring segment (111, 112, 113, 114) when the three-dimensional helix is ​​compressed in the axial direction of the three-dimensional helix, It is characterized in that The plurality of ring segments (111, 112, 113, 114) include a stabilizer ring segment (114) which does not have any electrodes, wherein the stabilizer ring segment (114) is the closest ring segment among the plurality of ring segments (111, 112, 113, 114), wherein a diameter of the stabilizer ring segment (114) is smaller than a diameter of an adjacent ring segment (111).

2. The catheter (1) according to claim 1, characterized in that The ablation portion (11) includes a plurality of mapping electrodes (115), and the mapping electrodes (115) are configured to receive electrical signals from vascular tissue.

3. The catheter (1) according to claim 1 or 2, characterized in that The second ring segment (112) of the plurality of ring segments (111, 112, 113, 114) includes a plurality of ablation electrodes (110) and / or a plurality of mapping electrodes (115).

4. The catheter (1) according to claim 3, characterized in that The ablation electrodes (110) of the second ring segment (112) are arranged in a staggered manner relative to the ablation electrodes (110) of the first ring segment (111).

5. The catheter (1) according to claim 2, characterized in that The third ring segment (113) of the plurality of ring segments (111, 112, 113, 114) has the plurality of mapping electrodes (115).

6. The catheter (1) according to claim 1 or 2, characterized in that The ablation catheter (1) is configured to deliver energy to vascular tissue via the ablation electrode (110).

7. The catheter (1) according to claim 1 or 2, characterized in that The ablation electrode (110) is an irrigated ablation electrode (110).

8. The catheter (1) according to claim 1 or 2, characterized in that The ablation electrode (110) is sleeve-shaped.

9. The catheter (1) according to claim 1 or 2, characterized in that The material of the ablation electrode (110) includes at least one of gold and platinum / iridium alloy.

10. The catheter (1) according to claim 1 or 2, characterized in that The ablation portion (11) comprises a shape memory material.

11. The catheter (1) according to claim 10, characterized in that The ablation portion (11) comprises an inner support element having shape memory properties.

12. The catheter (1) according to claim 1 or 2, characterized in that The ablation catheter (1) comprises a steerable delivery sheath (12).

Images