Devices and methods for steering electrical stimulation in cardiac rhythm management

• US 8,326,423 B2
• Filed: 06/26/2008
• Issued: 12/04/2012
• Est. Priority Date: 12/20/2004
• Status: Active Grant

• Current Assignee: Newstim, Inc.
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Zhu, Qingsheng, Ortega, Daniel Felipe
• Primary Examiner(s): DIETRICH, JOSEPH M
• Application Number:
  US12/147,317
• Publication Number:
  US 20080319499A1
• Time in Patent Office: 1,622 Days
• Field of Search: 607/15, 607/27, 607/122, 607/126, 607/127, 607/128
• US Class Current: 607/27
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/37 Monitoring; Protecting

Abstract

Tools and methods are particularly suited for certain cardiac conditions involving use of a catheter for pacing of the right and left ventricles from a lead in the right ventricle, e.g., to facilitate mechanically and/or electrically synchronous contractions for resynchronization. Certain aspects involve pacing and/or mapping by delivering pulses to a cardiac site useful for improving heart function as measured, e.g., by QRS width, fractionation, late LV activation timing, mechanical synchronicity of free wall and septal wall, effective throughput/pressure, or a combination thereof. In one embodiment, a catheter arrangement includes a fixation mechanism to attach the catheter arrangement to heart tissue, individually-addressable electrodes for providing pacing signals to the heart tissue, and an elongated structure that supports the fixation mechanism and the electrodes. The elongated structure is used to direct an end thereof to the target region in the right ventricle, and deliver an electrical pacing signal to different portions within the target region of the heart when the fixation mechanism is operative to attach to heart tissue and also when the fixation mechanism is not attaching the catheter arrangement to heart tissue.

Claims

1. An apparatus comprising:

a catheter arrangement configured for use in capturing myocardium of a heart, the catheter arrangement comprising;

a fixation mechanism to attach the catheter arrangement to heart tissue at a target region in a right ventricle of the heart at or near the His bundle and distal from an apex of the right ventricle;

individually-addressable electrodes for providing pacing signals to different portions within the target region of the heart tissue; and

an elongated structure to

support the fixation mechanism and the individually-addressable electrodes, and

direct an end of the elongated structure to the target region in the right ventricle; and

a pulse generation circuit electrically coupled to the individually-addressable electrodes and configured to generate pacing signals for delivery to the heart via the individually-addressable electrodes, the pacing signals comprising at least partially overlapping opposite polarity signals, and wherein the pulse generation circuit is configured to change the pacing signals from a first mode to a second mode responsive to the fixation mechanism being attached to the heart tissue.

2. The catheter arrangement of claim 1, wherein the pulse generation circuit is configured to generate pacing signals in the second mode when the electrodes are arranged to physically contact the heart tissue.

3. The apparatus of claim 1, wherein the elongated structure comprises an inner and an outer sheath movable with respect to each other, wherein the individually addressable electrodes are located on the inner sheath.

4. The apparatus of claim 3, wherein the elongated structure includes a pacing lead movable with respect to the inner and outer sheath, the pacing lead comprising an electrode configured for delivery of pacing signals after the inner and outer sheaths have been removed.

5. The apparatus of claim 1, wherein the second pacing mode includes an AV delay of approximately half an intrinsic AV delay.

6. A method for treating an asynchronous condition of a heart, the method comprising:

placing at least a first electrode at a location on a septal wall at or near a His bundle in a right ventricle of the heart and distal from an apex of the right ventricle;

pacing, using at least partially overlapping opposite polarity pulses, the right ventricle and a left ventricle of the heart for synchronous contraction of the right and left ventricles using at least the first electrode at the location in the right ventricle;

determining that a pacing threshold voltage has increased; and

responsive to determining that the pacing voltage threshold has increased, adjusting an overlap duration of the pacing pulses;

wherein the placement of the at least a first electrode is defined by one of improving, relative to intrinsic activity, a QRS width of the patient, a fractionation of the patient, and a timing of electrical stimulation of a late activation site of the left ventricle relative to the QRS.

7. The method of claim 6, wherein placing the first electrode comprises affixing a pacing lead to heart tissue.

8. The method of claim 7, wherein placing at least a first electrode comprises removing an outer sheath.

9. The method of claim 8, wherein removing the outer sheath comprises using a guide wire to maintain the position of the pacing lead as the outer sheath is removed.

10. The method of claim 6, wherein the pacing pulses are changed from a first mode to a second mode responsive to the fixation mechanism being attached to the heart tissue.

11. The method of claim 10, wherein the second mode includes generating pacing signals including an AV delay of approximately half an intrinsic AV delay.

12. A method for determining a pacing location using a catheter arranged to provide pacing in a right ventricle of a heart, the method comprising:

assessing a pacing location by delivering a pacing signal to a location in the right ventricle at a location on a septum at or near a His bundle and distal from an apex of the right ventricle, the pacing signal including at least partially overlapping opposite polarity pulses;

assessing the effectiveness of the delivered pacing signal as a function of at least one of a QRS width, fractionation, and a timing of electrical stimulation of a late activation site of a left ventricle relative to the QRS;

adjusting the catheter to change the pacing location;

repeating, for the changed pacing location, the assessing the pacing location and assessing the effectiveness;

fixing the location of the pacing location in response to a result of the step of assessing the effectiveness;

providing chronic pacing at the location;

determining that a pacing threshold voltage has increased; and

responsive to determining that the pacing voltage threshold has increased, adjusting an overlap duration of the pacing signal.

13. The method of claim 12, wherein the delivered pacing signal is delivered from an electrode affixed to an inner sheath of a catheter;

and

wherein fixing the location of the pacing location in response to a result of assessing the effectiveness comprises;

removing the inner sheath and fixing a pacing lead to the location; and

providing the chronic pacing utilizing the pacing lead.

14. The method of claim 13, wherein fixing the location of the pacing location comprises removing an outer sheath.

15. The method of claim 14, wherein removing the outer sheath comprises using a guide wire to maintain the position of the pacing lead as the outer sheath is removed.

16. The method of claim 13, comprising connecting the inner sheath to an external pacing circuit for delivering the pacing signal used for assessing the pacing location.

17. The method of claim 12, wherein the pacing signals are changed from a first mode to a second mode responsive to a fixation mechanism being attached to the heart tissue.

18. The method of claim 17, wherein the second pacing mode includes delivering pacing signals including an AV delay of approximately half an intrinsic AV delay.