US-12622746-B2 - Apparatus and methods for reducing microbubbles formation during cardiac ablation

Abstract

Various aspects of the present disclosure are directed towards apparatuses, systems, and methods for electroporation ablation. The electroporation ablation catheter may include an electrode assembly comprising one or more electrodes configured to generate electric fields in target tissue in response to a plurality of electrical pulse sequences delivered in a plurality of therapy sections, and an ultrasound transducer configured to generate a first set of ultrasound signals during a first electrical pulse sequence of the plurality of electrical pulse sequences and generate a second set of ultrasound signals after an end of the first electrical pulse sequence and before a beginning of a second electrical pulse sequence, the second electrical pulse sequence being an electrical pulse sequence subsequent to the first electrical pulse sequence.

Inventors

• El Yacine Alex Smail

Assignees

• BOSTON SCIENTIFIC SCIMED INC.

Dates

Publication Date

20260512

Application Date

20220518

Claims (18)

1. 1 . An electroporation ablation catheter, comprising: an electrode assembly comprising: one or more electrodes configured to generate electric fields in target tissue in response to a plurality of electrical pulse sequences delivered in a plurality of therapy sections to effect electroporation of the target tissue; and an ultrasound transducer configured to generate a first set of ultrasound signals concurrently with a first electrical pulse sequence of the plurality of electrical pulse sequences and generate a second set of ultrasound signals after an end of the first electrical pulse sequence and before a beginning of a second electrical pulse sequence, the second electrical pulse sequence being an electrical pulse sequence subsequent to the first electrical pulse sequence; wherein the first set of ultrasound signals has a first average magnitude; wherein the second set of ultrasound signals has a second average magnitude; and wherein the first average magnitude is different from the second average magnitude.
2. 2 . The electroporation ablation catheter of claim 1 , wherein the first average magnitude is lower than the second average magnitude.
3. 3 . The electroporation ablation catheter of claim 1 , wherein the electrode assembly further comprises an internal component disposed at an interior cavity of the electrode assembly; and wherein the ultrasound transducer is disposed on the internal component.
4. 4 . The electroporation ablation catheter of claim 1 , further comprising one or more wirings to power up the ablation catheter and to control at least one of a magnitude and frequency of the first set and the second set of ultrasound signals.
5. 5 . The electroporation ablation catheter of claim 1 , wherein the electrode assembly further comprises a plurality of splines; wherein the ultrasound transducer comprises one ultrasound transducer disposed on one of the plurality of splines.
6. 6 . The electroporation ablation catheter of claim 1 , wherein the first set of ultrasound signals has a first average frequency, wherein the second set of ultrasound signals has a second average frequency, wherein the first average frequency is different from the second average frequency.
7. 7 . An electroporation ablation catheter, comprising: an elongated shaft having a distal end; and an electrode assembly coupled to the distal end, the electrode assembly comprising: one or more electrodes configured to generate electric fields to effect electroporation in target tissue in response to a plurality of electrical pulse sequences delivered in a plurality of therapy sections, the electrode assembly configurable in an expanded configuration to define an interior cavity; an ultrasound transducer configured to generate a first set of ultrasound signals during a first electrical pulse sequence of the plurality of electrical pulse sequences and generate a second set of ultrasound signals after an end of the first electrical pulse sequence and before a beginning of a second electrical pulse sequence, the second electrical pulse sequence being an electrical pulse sequence subsequent to the first electrical pulse sequence; and an internal component extending from the distal end of the shaft and disposed in the interior cavity of the electrode assembly; and wherein the ultrasound transducer is disposed on the internal component.
8. 8 . The electroporation ablation catheter of claim 7 , wherein the first set of ultrasound signals has a first average magnitude, the second set of ultrasound signals has a second average magnitude; and wherein the first average magnitude is different from the second average magnitude.
9. 9 . The electroporation ablation catheter of claim 8 , wherein the first average magnitude is lower than the second average magnitude.
10. 10 . The electroporation ablation catheter of claim 7 , wherein the internal component comprises a deployment shaft.
11. 11 . The electroporation ablation catheter of claim 10 , further comprising: a catheter shaft having a proximal end and a distal end; wherein the electrode assembly extends from the distal end of the catheter shaft; and wherein the deployment shaft extends from the distal end of the catheter shaft.
12. 12 . The electroporation ablation catheter of claim 7 , wherein the electrode assembly further comprises a plurality of splines; wherein the ultrasound transducer comprises one ultrasound transducer disposed on one of the plurality of splines.
13. 13 . The electroporation ablation catheter of claim 12 , wherein at least a part of the plurality of splines form an interior cavity.
14. 14 . The electroporation ablation catheter of claim 7 , wherein the first set of ultrasound signals has a first average frequency, wherein the second set of ultrasound signals has a second average frequency, wherein the first average frequency is different from the second average frequency.
15. 15 . A method of reducing microbubbles formation during cardiac ablation, comprising: disposing an electroporation catheter proximate to target tissue, the electroporation catheter comprising one or more electrodes and an ultrasound transducer; generating an electric field, by the one or more electrodes, proximate to the target tissue in response to a plurality of electrical pulse sequences delivered in a plurality of therapy sections, the electric field having electric field strength sufficient to ablate the target tissue via irreversible electroporation; generating, by the ultrasound transducer, a set of ultrasound signals, wherein the set of ultrasound signals comprises a first set of ultrasound signals and a second set of ultrasound signals.
16. 16 . The method of claim 15 , wherein the first set of ultrasound signals is generated during a first electrical pulse sequence of the plurality of electrical pulse sequences.
17. 17 . The method of claim 15 , wherein the second set of ultrasound signals is generated after an end of the first electrical pulse sequence and before a beginning of a second electrical pulse sequence.
18. 18 . The method of of claim 15 , wherein the first set of ultrasound signals has a first average magnitude; wherein the second set of ultrasound signals has a second average magnitude; and wherein the first average magnitude is different from the second average magnitude.

Description

CROSS REFERENCE TO RELATED APPLICATION This application claims priority to Provisional Application No. 63/191,134, filed May 20, 2021, which is herein incorporated by reference in its entirety. TECHNICAL FIELD The present disclosure relates to medical apparatus, systems, and methods for reducing or preventing microbubbles during cardiac ablation by irreversible electroporation. BACKGROUND Ablation procedures are used to treat many different conditions in patients. Ablation may be used to treat cardiac arrhythmias, benign tumors, cancerous tumors, and to control bleeding during surgery. Usually, ablation is accomplished through thermal ablation techniques including radio-frequency (RF) ablation and cryoablation. In RF ablation, a probe is inserted into the patient and radio frequency waves are transmitted through the probe to the surrounding tissue. The radio frequency waves generate heat, which destroys surrounding tissue and cauterizes blood vessels. In cryoablation, a hollow needle or cryoprobe is inserted into the patient and cold, thermally conductive fluid is circulated through the probe to freeze and kill the surrounding tissue. RF ablation and cryoablation techniques indiscriminately kill tissue through cell necrosis, which may damage or kill otherwise healthy tissue, such as tissue in the esophagus, phrenic nerve cells, and tissue in the coronary arteries. Another ablation technique uses electroporation. In electroporation, or electro-permeabilization, an electric field is applied to cells to increase the permeability of the cell membrane. The electroporation may be reversible or irreversible, depending on the strength of the electric field. If the electroporation is reversible, the increased permeability of the cell membrane may be used to introduce chemicals, drugs, and/or deoxyribonucleic acid (DNA) into the cell, prior to the cell healing and recovering. If the electroporation is irreversible, the affected cells are killed through apoptosis. Irreversible electroporation (IRE) may be used as a nonthermal ablation technique. In IRE, trains of short, high voltage pulses are used to generate electric fields that are strong enough to kill cells through apoptosis. In ablation of cardiac tissue, IRE may be a safe and effective alternative to the indiscriminate killing of thermal ablation techniques, such as RF ablation and cryoablation. IRE may be used to kill target tissue, such as myocardium tissue, by using an electric field strength and duration that kills the target tissue but does not permanently damage other cells or tissue, such as non-targeted myocardium tissue, red blood cells, vascular smooth muscle tissue, endothelium tissue, and nerve cells. In some IRE procedures, there is a possibility of microbubble forming during the treatment of the patient. The formation of microbubbles can cause tissue damage and increase risk for treatment of the patient. A way to prevent the formation of microbubbles during IRE procedures is needed. SUMMARY In Example 1, an electroporation ablation catheter comprises an electrode assembly. The electrode assembly comprises one or more electrodes configured to generate electric fields in target tissue in response to a plurality of electrical pulse sequences delivered in a plurality of therapy sections, and an ultrasound transducer configured to generate a first set of ultrasound signals during a first electrical pulse sequence of the plurality of electrical pulse sequences and generate a second set of ultrasound signals after an end of the first electrical pulse sequence and before a beginning of a second electrical pulse sequence, the second electrical pulse sequence being an electrical pulse sequence subsequent to the first electrical pulse sequence, wherein the first set of ultrasound signals has a first average magnitude, the second set of ultrasound signals has a second average magnitude, and the first average magnitude is different from the second average magnitude. In Example 2, the electroporation ablation catheter of Example 1, wherein the first average magnitude is lower than the second average magnitude. In Example 3, the electroporation ablation catheter of Example 1 or 2, wherein the electrode assembly further comprises an internal component disposed at an interior cavity of the electrode assembly, and the ultrasound transducer is disposed on the internal component. In Example 4, the electroporation ablation catheter of any of Examples 1-3, further comprising one or more wirings to power up the ablation catheter and to control at least one of a magnitude and frequency of the first set and the second set of ultrasound signals. In Example 5, the electroporation ablation catheter of any of Examples 1-4, wherein the electrode assembly further comprises a plurality of splines, and wherein the ultrasound transducer comprises one ultrasound transducer disposed on one of the plurality of splines. In Example 6, the electroporation ablation catheter of any of Exa