Sheath visualization method by means of impedance localization and magnetic information

Patent metadata

Field	Value
Publication number	US-10398347-B2
Application number	US-201514974878-A
Country	US
Kind code	B2
Filing date	Dec 18, 2015
Priority date	Dec 18, 2015
Publication date	Sep 3, 2019
Grant date	Sep 3, 2019

Abstract

Catheterization is carried out by inserting a sheath into a human patient and moving a catheter having an electrode through the sheath lumen. A variation between a first threshold value and a second threshold value in electrical current through the electrode is identified. Responsively to the variation, it is reported that a portion of the catheter has transitioned between an in-sheath condition and an out-of-sheath condition. The sheath is defined and identified by the historical data of the readings of the magnetic sensor during its movements.

First claim

The invention claimed is:

1. A method, comprising the steps of:
inserting a sheath into a human patient, the sheath having a lumen, an outer wall having a perforation formed therethrough and a distal end;
moving a catheter through the lumen of the sheath, the catheter having a distal portion and at least one electrode disposed on the distal portion, the electrode being connected to current-measuring circuitry;
measuring electrical current through the electrode with the current-measuring circuitry;
identifying a variation in the electrical current between a first threshold value and a second threshold value while the electrode is passing by the perforation; and
responsively to the variation, reporting that a portion of the catheter has transitioned between an in-sheath condition and an out-of-sheath condition.

2. The method according to claim 1 , wherein the electrode and the current-measuring circuitry is a component of an impedance measuring system and wherein measuring electrical current comprises measuring an impedance of a heart with the electrode.

3. The method according to claim 1 , wherein the at least one electrode comprises a plurality of electrodes:
while performing the step of moving the catheter, concurrently measuring electrical current in the plurality of electrodes, respectively, wherein identifying a variation comprises recognizing a transient decrease in current flow in one of the electrodes that does not fall below a lower threshold; and
concluding that a position of the one electrode opposes the perforation during the transient decrease.

4. The method according to claim 3 , further comprising: responsively to identifying a variation determining a location of the distal end of the catheter relative to the perforation.

5. The method according to claim 1 , wherein the portion of the catheter is the distal end of the catheter.

6. The method according to claim 1 , wherein the portion of the catheter is another electrode.

7. The method according to claim 1 , wherein a magnetic sensor is disposed in the catheter at a predetermined distance from the distal end, and reporting comprises reading the magnetic sensor, and reporting a location of the distal end of the catheter from the reading using the predetermined distance.

Assignees

• Biosense Webster Israel Ltd

Inventors

• Pressman Assaf
• Raz Shaul Haim
• Rosenberg Avigdor
• Berman Dror

Classifications

• A61B5/746

  Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms · CPC title

• A61B5/6885

  Monitoring or controlling sensor contact pressure · CPC title

• A61B5/6852

  Catheters · CPC title

• A61B18/12

  by passing a current through the tissue to be heated, e.g. high-frequency current · CPC title

• A61B2018/00589

  Coagulation · CPC title