SYSTEM AND METHOD FOR USING TISSUE CONTACT INFORMATION IN AN AUTOMATED MAPPING OF CARDIAC CHAMBERS EMPLOYING MAGNETICLY SHAPED FIELDS

• US 20100305429A1
• Filed: 02/17/2010
• Published: 12/02/2010
• Est. Priority Date: 05/29/2009
• Status: Active Grant

• Current Assignee: Neuro-Kinesis Corporation
• Original Assignee: Magnetecs Incorporated
• Inventors: Gang, Eli, Shachar, Yehoshua, Farkas, Laszlo, Farkas, Leslie, Marx, Bruce
• Granted Patent: US 8,986,214 B2
• Time in Patent Office: Days
• US Class Current: 600/424
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61B 5/1075 for measuring dimensions by non-invasive methods, e.g. for determining thickness of tissue layer A61B8/0858 takes precedence
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/6851 Guide wires
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 5/6885 Monitoring or controlling sensor contact pressure

Abstract

The invention relates to a method for using tissue contact technology to optimize automated cardiac chamber mapping algorithms to both speed up the mapping process and guarantee the definition of the actual chamber limits. The invention further comprises a method for conveying tissue type information to such automatic mapping algorithms so as to allow them to adapt their point collection density within areas of particular interest. The method is enhanced by the use of a magnetic chamber that employs electromagnetic coils configured as a waveguide that radiate magnetic fields by shaping the necessary flux density axis on and around the catheter distal tip so as to push, pull and rotate the tip on demand and as defined by such automatic mapping algorithms.

Claims

1. A method for automatically mapping the interior surface of a coronary chamber comprising:

inserting a catheter with an array of electrodes disposed on its surface into the coronary chamber;

generating a shaped magnetic field around the catheter and coronary chamber;

receiving a plurality of signals from the electrode array disposed on the catheter;

calculating the actual position of the catheter within the coronary chamber from the plurality of received signals;

determining the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber from the plurality of received signals;

optimizing a mapping pattern of the catheter based on the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber;

obtaining a plurality of measurements from the surface of the coronary chamber when continuous contact has been established; and

generating a map of the coronary chamber based on the obtained continuous contact measurements.

2. The method of claim 1 where receiving a plurality of signals from the electrode array disposed on the catheter comprises collecting a plurality of impedance measurements obtained from the coronary chamber and where determining the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber comprises determining the presence of continuous or intermittent contact based on the impedance measurements obtained by the electrode array.

3. The method of claim 1 where optimizing the mapping pattern of the catheter based on the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber comprises:

guiding the catheter towards the surface of the coronary chamber until continuous contact between the coronary chamber and the catheter is determined;

maintaining surface contact between the coronary chamber and the distal tip of the catheter over several systole/diastole cycles; and

retracting the catheter from the surface of the coronary chamber until intermittent contact between the coronary chamber and the catheter is determined.

4. The method of claim 3 wherein the steps of guiding the catheter towards the coronary chamber surface and retracting the catheter away from the coronary chamber surface comprises altering the shape of the generated magnetic field and adjusting the field strength of the generated magnetic field.

5. The method of claim 3 where retracting the catheter away from the coronary chamber surface comprises retracting the catheter to a predetermined distance away from the surface of the coronary chamber.

6. The method of claim 3 further comprising repeating the steps of guiding, maintaining, and retracting the catheter for a plurality of different desired contact points along the surface of the coronary chamber.

7. The method of claim 1 where optimizing a mapping pattern of the catheter based on the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber comprises:

guiding the catheter from its actual position to the first of a series of predetermined desired positions along the surface of the coronary chamber;

obtaining a plurality of measurements from the first of a series of desired positions when continuous contact has been achieved;

retracting the catheter from the first of a series of desired positions; and

automatically guiding the catheter to the next predetermined desired position within the series until measurements have been obtained from every desired position within the predetermined series.

8. The method of claim 7 further comprising differentiating between at least two different types of tissue within the coronary chamber based on the measurements obtained at each of the desired positions.

9. The method of claim 8 further comprising adding the results of the tissue differentiation to the generated map of the coronary chamber.

10. A method for automatically mapping the interior surface of a coronary chamber using a shaped magnetic field comprising:

inserting a catheter with an array of electrodes disposed on its surface into the coronary chamber;

altering the shape and/or strength of the shaped magnetic field to guide the catheter to a series of desired positions along the surface of the coronary chamber, wherein the catheter achieves continuous surface contact with each desired position;

obtaining a plurality of measurements from the surface of the coronary chamber at each desired position when continuous contact has been established;

altering the shape and/or strength of the shaped magnetic field to retract the catheter from each desired position on the surface of the coronary chamber to a predetermined distance away from each desired position;

repeatedly and automatically altering the shape and/or strength of the shaped magnetic field to guide the catheter to the next desired position within the series on the surface of the coronary chamber until measurements have obtained from every desired position within the series; and

generating a map of the coronary chamber based on the continuous contact measurements obtained at each of the desired positions.

11. The method of claim 10 where obtaining a plurality of measurements from the surface of the coronary chamber at each desired position when continuous contact has been established comprises obtaining the impedance value at each desired position.

12. The method of claim 11 further comprising differentiating between at least two different types of tissue within the coronary chamber using the impedance value obtained at each desired position.

13. The method of claim 12 further comprising adding the results of the tissue differentiation to the generated map of the coronary chamber.

14. An apparatus for automatically mapping the interior surface of a coronary chamber comprising:

a catheter capable of entering the coronary chamber;

means for generating a shaped magnetic field around the catheter and coronary chamber;

means for determining the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber;

means for determining the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber;

means for optimizing a mapping pattern of the catheter based on the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber;

means for obtaining a plurality of measurements from the surface of the coronary chamber when continuous contact has been established; and

a display for displaying a map of the coronary chamber generated by the obtained continuous contact measurements.

15. The apparatus of claim 14 where the means for generating a shaped magnetic field around the catheter and coronary chamber comprises a plurality of electromagnetic coils disposed substantially symmetrically about the coronary chamber and catheter.

16. The apparatus of claim 14 where the means for determining the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber comprises a plurality of impedance sensing electrodes disposed on the surface of the catheter.

17. The apparatus of claim 14 where the means for optimizing a mapping pattern of the catheter based on the presence of continuous or intermittent contact between the catheter and the surface of the coronary chamber comprises means for the catheter to be guided to and retracted from the surface of the coronary chamber via the shaped magnetic field.

18. The apparatus of claim 14 where the means for obtaining a plurality of measurements from the surface of the coronary chamber when continuous contact has been established comprises means for differentiating between at least two different types of tissue within the coronary chamber.

19. The method of claim 18 further comprising means for adding the results of the tissue differentiation to the display of the map of the coronary chamber.

20. The apparatus of claim 14 further comprising means for preventing the catheter from exceeding a predetermined threshold distance from the surface of the coronary chamber.