US-12622756-B2 - Distal end assembly guidance

US12622756B2US 12622756 B2US12622756 B2US 12622756B2US-12622756-B2

Abstract

In one embodiment, a catheter alignment system includes a catheter to be inserted into a body part, and including catheter electrodes to contact tissue at respective locations within the body part, a display, and processing circuitry to receive signals provided by the catheter, assess respective levels of contact of ones of the catheter electrodes with the tissue of the body part responsively to the received signals, find a direction in which the catheter should be moved to improve at least one of the respective levels of contact of at least one of the catheter electrodes responsively to the respective levels of contact of the ones of the catheter electrodes, and render to the display a representation of the catheter responsively to the received signals, and a direction indicator indicating the direction in which the catheter should be moved responsively to the found direction.

Inventors

Avigdor Rosenberg

Assignees

BIOSENSE WEBSTER (ISRAEL) LTD.

Dates

Publication Date: 20260512
Application Date: 20231130

Claims (20)

1 . A catheter protection system, comprising: a sheath having a distal end, and configured to be inserted into a body part of a living subject; a catheter including a shaft having a distal portion, an expandable distal end assembly disposed distally to the distal portion, the catheter being configured to be inserted through the sheath with the distal portion and the expandable distal end assembly protruding from the sheath into the body part, the catheter including a pusher disposed in the shaft and coupled to the expandable distal end assembly such that adjusting the pusher longitudinally with respect to the shaft selectively elongates and shortens the distal end assembly; a position tracking sub-system configured to: track a relative position of the distal portion of the shaft and the distal end of the sheath; and find when the distal portion of the shaft enters the distal end of the sheath responsively to the tracked relative position; and a pusher actuator configured to automatically actuate the pusher to elongate the expandable distal end assembly responsibly to the distal portion of the shaft entering the distal end of the sheath.
2 . The catheter protection system according to claim 1 , further comprising a sound outputting device configured to provide an audible alert responsively to the distal portion of the shaft entering the distal end of the sheath.
3 . The catheter protection system according to claim 1 , wherein: the position tracking sub-system is configured to find when the distal portion of the shaft exits the distal end of the sheath responsively to the tracked relative position; and the pusher actuator is configured to automatically actuate the pusher to shorten the expandable distal end assembly responsibly to the distal portion of the shaft exiting the distal end of the sheath.
4 . The catheter protection system according to claim 3 , further comprising a sound outputting device configured to provide an audible alert responsively to the distal portion of the shaft exiting the distal end of the sheath.
5 . The catheter protection system according to claim 1 , wherein the position tracking sub-system comprises: generator coils configured to generate magnetic fields having different frequencies in the body part; a first magnetic coil sensor disposed proximally to the expandable distal end assembly at the distal portion of the shaft; and a second magnetic coil sensor disposed at the distal end of the sheath, the first and second magnetic coil sensors being configured to output respective electrical signals responsively to detecting the magnetic fields, the position tracking sub-system being configured to track the relative position of the distal portion of the shaft and the distal end of the sheath responsively to the output electrical signals.
6 . The catheter protection system according to claim 1 , wherein the expandable distal end assembly comprises an inflatable balloon.
7 . The catheter protection system according to claim 1 , wherein the expandable distal end assembly comprises a plurality of electrodes disposed thereon.
8 . The catheter protection system according to claim 7 , wherein the plurality of electrodes are configured to deliver ablative energy to tissue.
9 . The catheter protection system according to claim 1 , further comprising a force sensor configured to detect a force applied to the expandable distal end assembly.
10 . A catheter protection system, comprising: a sheath having a distal end, and configured to be inserted into a body part of a living subject; a catheter including a shaft having a distal portion, an expandable distal end assembly disposed distally to the distal portion, the catheter being configured to be inserted through the sheath with the distal portion and the expandable distal end assembly protruding from the sheath into the body part, the catheter including a pusher disposed in the shaft and coupled to the distal end assembly such that adjusting the pusher longitudinally with respect to the shaft selectively elongates and shortens the distal end assembly; a position tracking sub-system configured to: track a relative position of the distal portion of the shaft and the distal end of the sheath; and find when the distal portion of the shaft enters the distal end of the sheath responsively to the tracked relative position; and a sound outputting device configured to provide an audible alert responsibly to the distal portion of the shaft entering the distal end of the sheath.
11 . The catheter protection system according to claim 10 , wherein the position tracking sub-system comprises: a proximal electrode disposed proximally to the expandable distal end assembly on the distal portion of the shaft; and body surface electrodes configured to be attached to a skin surface of the living subject, the position tracking sub-system being configured to track the relative position of the distal portion of the shaft and the distal end of the sheath responsively to a measured electrical impedance between the proximal electrode and the body surface electrodes.
12 . The catheter protection system according to claim 10 , wherein: the position tracking sub-system is configured to find when the distal portion of the shaft exits the distal end of the sheath responsively to the tracked relative position; and the sound outputting device is configured to provide another audible alert responsibly to the distal portion of the shaft exiting the distal end of the sheath.
13 . The catheter protection system according to claim 10 , wherein the position tracking sub-system comprises: a proximal electrode disposed proximally to the expandable distal end assembly on the distal portion of the shaft; and body surface electrodes configured to be attached to a skin surface of the living subject, the position tracking sub-system being configured to track the relative position of the distal portion of the shaft and the distal end of the sheath responsively to a measured electrical impedance between the proximal electrode and the body surface electrodes.
14 . The catheter protection system according to claim 10 , wherein the position tracking sub-system comprises: generator coils configured to generate magnetic fields having different frequencies in the body part; a first magnetic coil sensor disposed proximally to the expandable distal end assembly at the distal portion of the shaft; and a second magnetic coil sensor disposed at the distal end of the sheath, the first and second magnetic coil sensors being configured to output respective electrical signals responsively to detecting the magnetic fields, the position tracking sub-system being configured to track the relative position of the distal portion of the shaft and the distal end of the sheath responsively to the output electrical signals.
15 . A catheter protection method, comprising: inserting a sheath into a body part of a living subject; inserting a catheter through the sheath with a distal portion of a shaft of the catheter and an expandable distal end assembly of the catheter protruding from the sheath into the body part; adjusting a pusher disposed in the shaft, and coupled to the expandable distal end assembly, longitudinally with respect to the shaft to selectively elongate and shorten the expandable distal end assembly; tracking a relative position of the distal portion of the shaft and the distal end of the sheath; finding when the distal portion of the shaft enters the distal end of the sheath responsively to the tracked relative position; and automatically actuating the pusher to elongate the expandable distal end assembly responsibly to the distal portion of the shaft entering the distal end of the sheath.
16 . The catheter protection method according to claim 15 , further comprising providing an audible alert responsively to the distal portion of the shaft entering the distal end of the sheath.
17 . The catheter protection method according to claim 15 , further comprising: finding when the distal portion of the shaft exits the distal end of the sheath responsively to the tracked relative position; and automatically actuating the pusher to shorten the expandable distal end assembly responsibly to the distal portion of the shaft exiting the distal end of the sheath.
18 . The catheter protection method according to claim 17 , further comprising provide an audible alert responsively to the distal portion of the shaft exiting the distal end of the sheath.
19 . The catheter protection method according to claim 15 , wherein the tracking comprises tracking the relative position of the distal portion of the shaft and the distal end of the sheath responsively to a measured electrical impedance between a proximal electrode disposed proximally to the expandable distal end assembly on the distal portion of the shaft and body surface electrodes attached to a skin surface of the living subject.
20 . The catheter protection method according to claim 15 , further comprising: generating magnetic fields having different frequencies in the body part; and outputting respective electrical signals by a first magnetic coil sensor disposed proximally to the expandable distal end assembly at the distal portion of the shaft and a second magnetic coil sensor disposed at the distal end of the sheath responsively to detecting the magnetic fields, wherein the tracking comprises tracking the relative position of the distal portion of the shaft and the distal end of the sheath responsively to the output electrical signals.

Description

RELATED APPLICATION INFORMATION This application is a divisional of prior filed U.S. patent application Ser. No. 17/168,123 filed on Feb. 4, 2021, which claims benefit of U.S. Provisional Patent Application No. 63/129,475 filed on Dec. 22, 2020, which prior application is hereby incorporated by reference as if set forth in full into this application. FIELD OF THE INVENTION The present invention relates to medical systems, and in particular, but not exclusively to, catheters with expandable distal end assemblies. BACKGROUND A wide range of medical procedures involve placing probes, such as catheters, within a patient's body. Location sensing systems have been developed for tracking such probes. Magnetic location sensing is one of the methods known in the art. In magnetic location sensing, magnetic field generators are typically placed at known locations external to the patient. A magnetic field sensor within the distal end of the probe generates electrical signals in response to these magnetic fields, which are processed to determine the coordinate locations of the distal end of the probe. These methods and systems are described in U.S. Pat. Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612 and 6,332,089, in PCT International Publication No. WO 1996/005768, and in U.S. Patent Application Publications Nos. 2002/0065455 and 2003/0120150 and 2004/0068178, whose disclosures are all incorporated herein by reference (see also the Appendix of prior filed Provisional Patent Application Ser. 63/129,475 filed on Dec. 22, 2020). Locations may also be tracked using impedance or current based systems. One medical procedure in which these types of probes or catheters have proved extremely useful is in the treatment of cardiac arrhythmias Cardiac arrhythmias and atrial fibrillation in particular, persist as common and dangerous medical ailments, especially in the aging population. Diagnosis and treatment of cardiac arrhythmias include mapping the electrical properties of heart tissue, especially the endocardium and the heart volume, and selectively ablating cardiac tissue by application of energy. Such ablation can cease or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions. Various energy delivery modalities have been disclosed for forming lesions, and include use of microwave, laser and more commonly, radiofrequency energies to create conduction blocks along the cardiac tissue wall. In a two-step procedure, mapping followed by ablation, electrical activity at points within the heart is typically sensed and measured by advancing a catheter containing one or more electrical sensors into the heart, and acquiring data at a multiplicity of points. These data are then utilized to select the endocardial target areas at which the ablation is to be performed. Electrode catheters have been in common use in medical practice for many years. They are used to stimulate and map electrical activity in the heart and to ablate sites of aberrant electrical activity. In use, the electrode catheter is inserted into a major vein or artery, e.g., femoral artery, and then guided into the chamber of the heart of concern. A typical ablation procedure involves the insertion of a catheter having a one or more electrodes at its distal end into a heart chamber. A reference electrode may be provided, generally taped to the skin of the patient or by means of a second catheter that is positioned in or near the heart. RF (radio frequency) current is applied to the tip electrode(s) of the ablating catheter, and current flows through the media that surrounds it, i.e., blood and tissue, toward the reference electrode. The distribution of current depends on the amount of electrode surface in contact with the tissue as compared to blood, which has a higher conductivity than the tissue. Heating of the tissue occurs due to its electrical resistance. The tissue is heated sufficiently to cause cellular destruction in the cardiac tissue resulting in formation of a lesion within the cardiac tissue which is electrically non-conductive. Therefore, when placing an ablation or other catheter within the body, particularly near the endocardial tissue, it is desirable to have the distal tip of the catheter in direct contact with the tissue. The contact can be verified, for example, by measuring the contact between the distal tip and the body tissue. U.S. Patent Application Publication Nos. 2007/0100332, 2009/0093806 and 2009/0138007, whose disclosures are incorporated herein by reference (see also the Appendix of priority Provisional Patent Application Ser. No. 63/129,475 filed on Dec. 22, 2020) describe methods of sensing contact pressure between the distal tip of a catheter and tissue in a body cavity using a force sensor embedded in the catheter. A number of references have reported methods to determine electrode-ti