Apparatus and method for detecting contact pressure

• US 5,396,887 A
• Filed: 09/23/1993
• Issued: 03/14/1995
• Est. Priority Date: 09/23/1993
• Status: Expired due to Fees

• Current Assignee: Cardiac Pathways Corp. (Boston Scientific Corporation)
• Original Assignee: Cardiac Pathways Corp. (Boston Scientific Corporation)
• Inventors: Imran, Mir A.
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US08/126,045
• Time in Patent Office: 537 Days
• Field of Search: 128/774, 128/642, 606/40, 606/46, 607/119, 607/122, 607/154
• US Class Current: 600/374
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/00601 Cutting
• CPC Class Codes: A61B 2034/2063 Acoustic tracking systems, e.g. using ultrasound
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/6858 with a distal basket, e.g. expandable basket
• CPC Class Codes: A61B 5/6885 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for

Abstract

An apparatus for performing an operation inside a body in the vicinity of a wall therein which includes a flexible elongate member having proximal and distal extremities. The distal extremity is adapted to be inserted into the body for performing the operation therein and the proximal extremity is adapted to be disposed outside the body. A pressure sensor is carried by the distal extremity of the flexible elongate tubular member for sensing the force being applied to the distal extremity in bringing it into engagement with the wall so that the force being applied to the distal extremity can be controlled.

Claims

1. In an apparatus for performing a procedure in a chamber defined by a wall of a heart in a body in the vicinity of the wall, a flexible elongate member having proximal and distal extremities, the distal extremity being adapted to be inserted into the heart for performing the procedure therein and the flexible elongate member having a length so that the proximal extremity is disposed outside the body when the distal extremity is in the heart, the flexible elongate member having a column strength so that a force provided to the proximal extremity causes the distal extremity to engage the wall of the chamber, a pressure sensor carried by the distal extremity of the flexible elongate member and generating an electrical signal, electrical conductive means connected to the pressure sensor and extending to the proximal extremity, the pressure sensor included within means for sensing the pressure being applied by the distal extremity against the wall to ensure that a pressure sufficient to puncture the wall is not exerted on the distal extremity during the procedure.

2. The apparatus of claim 1 together with an ablation electrode carried by the distal extremity distal of the pressure sensor.

3. The apparatus of claim 2 wherein the ablation electrode is carried by the pressure sensor.

4. The apparatus of claim 1 wherein the pressure sensor means includes electrical means for adjusting an electrical signal to reflect the force being applied to the distal extremity.

5. The apparatus of claim 4 wherein the electrical means includes a layer of insulating material having a surface with first and second interspaced conductive elements carried thereby and a layer of carbon particles overlying the conductive elements.

6. A method for use with an apparatus having a flexible elongate member with proximal and distal extremities to dispose the distal extremity in a chamber defined by a wall of a heart in a body for performing a procedure in the vicinity of the wall comprising the steps of introducing the distal extremity of the flexible elongate member via a lumen into the chamber, applying a force to the proximal extremity of the flexible elongate member so that the distal extremity engages the wall, sensing the contact pressure of the distal extremity against the wall to obtain information regarding the magnitude of the contact pressure and utilizing the information to ensure that a force is not applied to the proximal extremity which is sufficient to cause the distal extremity to puncture the wall during the procedure.

7. The method of claim 6 together with the step of sensing electrical impulses from the wall.

8. The method of claim 6 together with the step of performing ablations in the wall.

9. In an apparatus for use for ablation in a wall of a heart in a body of a patient, a flexible elongate member having proximal and distal extremities, the distal extremity being adapted to be inserted into the body and the flexible elongate member having a length so that the proximal extremity is disposed outside the body when the distal extremity is in the heart, an ablation electrode formed of a conductive material adapted to engage the wall mounted on the distal extremity of the flexible elongate member, conductive means connected to the ablation electrode and extending to the proximal extremity, pressure sensing means mounted in the distal extremity of the flexible elongate member and sensing the pressure being applied by the ablation electrode to the wall whereby it can be ascertained whether the ablation electrode is in intimate contact with the wall of the heart and also ascertained that the pressure exerted on the wall of the heart is insufficient to puncture the surface of the wall of the heart, the pressure sensing means creating an electrical output and electrical conductive means connected to the pressure sensing means and extending to the proximal extremity.

10. The apparatus of claim 9 wherein the pressure sensing means includes electrical means for adjusting the electrical output to reflect the pressure force being applied by the ablation electrode to the wall.

11. The apparatus of claim 10 wherein the electrical means includes a layer of insulating material having a surface with first and second interspaced conductive elements carried thereby and a layer of carbon particles overlying the conductive elements.

12. The apparatus of claim 9 wherein the conductive material of the ablation electrode extends around the distal extremity.