METHOD AND DEVICE FOR TREATING MYOCARDIAL ISCHEMIA

• US 20080119904A1
• Filed: 11/17/2006
• Published: 05/22/2008
• Est. Priority Date: 11/17/2006
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Baynham, Tamara Colette, Shuros, Allan C., Salo, Rodney W.
• Granted Patent: US 7,941,216 B2
• Time in Patent Office: Days
• US Class Current: 607/19
• 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 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/36843 Bi-ventricular stimulation

Abstract

A method and device for treating myocardial ischemia are described in which the stress experienced by a myocardial region identified as vulnerable to becoming ischemic is varied with pre-excitation pacing. In an unloading mode, pacing is applied in proximity to the vulnerable region to reduce stress and the metabolic demand of the region. In a loading mode, pacing is applied to a region remote from the vulnerable region in order to produce a conditioning effect.

Claims

1. A method, comprising:

identifying a vulnerable ventricular region in a patient that is predisposed to becoming ischemic;

implanting a cardiac pacing device having first and second electrodes;

implanting the first electrode near the ventricular region vulnerable to ischemia so that a pacing pulse from the first electrode unloads the vulnerable region during systole as compared with an intrinsic beat;

implanting the second electrode near a ventricular region remote from the vulnerable region so that a pacing pulse from the second electrode loads the vulnerable region during systole as compared with an intrinsic beat;

configuring the device to operate in a vulnerable region unloading mode that delivers pacing pulses through a pacing channel configured with the first electrode; and

,

configuring the device to intermittently operate in a vulnerable region loading mode that delivers pacing pulses through a pacing channel configured with the second electrode.

2. The method of claim 1 further comprising:

configuring the device to sense a variable that can be correlated with the occurrence of myocardial ischemia and to detect the presence or absence of myocardial ischemia in accordance with the sensed variable;

configuring the device to intermittently switch to the vulnerable region loading mode according to a defined schedule but to switch to the vulnerable region loading mode only if the sensed variable indicates the absence of myocardial ischemia.

3. The method of claim 1 further comprising:

configuring the device to sense a variable related to the patient'"'"'s exertion level;

configuring the device to intermittently switch to the vulnerable region loading mode but to switch to the vulnerable region loading mode only if the sensed variable is within a specified range.

4. The method of claim 1 further comprising

configuring the device to sense a variable that can be correlated with the occurrence of myocardial ischemia and to detect the presence or absence of myocardial ischemia in accordance with the sensed variable;

and,

configuring the device to switch from a normal mode to the vulnerable region unloading mode if the sensed variable indicates the presence of myocardial ischemia, wherein the normal mode may or may not deliver pacing therapy.

5. The method of claim 1 further comprising:

measuring the patient'"'"'s intrinsic AV interval;

configuring the device to deliver pacing pulses in accordance with an atrial tracking or AV sequential pacing mode with a specified AV delay interval in the vulnerable region unloading and vulnerable region loading modes; and

,

setting the AV delay interval to be shorter than the measured intrinsic AV interval.

6. The method of claim 5 further comprising setting the AV delay interval to be between 30 and 80% of the measured intrinsic AV interval.

7. The method of claim 1 further comprising:

configuring the device to sense a variable related to the patient'"'"'s exertion level;

configuring the device to deliver pacing pulses in accordance with an atrial tracking or AV sequential pacing mode with a specified AV delay interval in the vulnerable region unloading mode; and

,

configuring the device to dynamically adjust the AV delay interval in accordance with the sensed variable.

8. The method of claim 1 further comprising:

configuring the device to sense a variable related to the patient'"'"'s exertion level;

configuring the device to deliver pacing pulses in accordance with an atrial tracking or AV sequential pacing mode with a specified AV delay interval in the vulnerable region loading mode; and

,

configuring the device to dynamically adjust the AV delay interval in accordance with the sensed variable.

9. The method of claim 1 further comprising providing the patient with a means for switching the device to the vulnerable region loading mode.

10. The method of claim 1 further comprising providing the patient with a means for switching the device to the vulnerable region unloading mode upon experiencing symptoms of myocardial ischemia.

11. A cardiac device, comprising:

an implantable housing for containing electronic circuitry;

a sensor for sensing a variable that can be correlated with the occurrence of myocardial ischemia in a patient;

a first electrode adapted for disposition near a ventricular region vulnerable to ischemia;

a second electrode adapted for disposition near a ventricular region remote from the vulnerable region;

a pulse generator for outputting pacing pulses;

a controller programmed to deliver pacing pulses through a pacing channel in accordance with a programmed pacing mode;

wherein the controller is programmed to detect the presence or absence of myocardial ischemia in accordance with the sensed variable;

wherein the controller is programmed to operate in a vulnerable region unloading mode that delivers pacing pulses through a pacing channel configured with the first electrode or a vulnerable region loading mode that delivers pacing pulses through a pacing channel configured with the second electrode; and

,

wherein the controller is programmed to operate in the vulnerable region unloading mode if the sensed variable indicates the presence of myocardial ischemia and operate in the vulnerable region loading mode if the sensed variable indicates the absence of myocardial ischemia.

12. The device of claim 11 wherein the sensor is a cardiac sensing channel for sensing cardiac electrical activity, the sensed variable is an electrogram and wherein the controller is programmed to detect the presence of myocardial ischemia if a current of injury is found in the electrogram.

13. The device of claim 11 wherein the sensor is a cardiac sensing channel for sensing cardiac electrical activity and the sensed variable is heart rate.

14. The device of claim 11 wherein the sensor is an accelerometer for measuring the patient'"'"'s activity level.

15. The device of claim 11 wherein the sensor is a minute ventilation sensor.

16. The device of claim 11 wherein the controller is programmed to:

switch to the vulnerable region unloading mode whenever the sensed variable indicates the presence of myocardial ischemia; and

,

switch to the vulnerable region loading mode whenever the sensed variable indicates the absence of myocardial ischemia.

17. The device of claim 11 wherein the controller is programmed to intermittently switch to the vulnerable region loading mode if the sensed variable indicates the absence of myocardial ischemia.

18. The device of claim 11 further comprising:

a third electrode adapted for disposition near a ventricular region apart from the locations of the first and second electrodes;

wherein the controller is programmed to operate in a normal mode that delivers pacing pulses through a pacing channel configured with the third electrode; and

,

wherein the controller is programmed to;

switch to the vulnerable region unloading mode whenever the sensed variable indicates the presence of myocardial ischemia; and

,

operate intermittently in either the vulnerable region loading mode or the normal mode whenever the sensed variable indicates the absence of myocardial ischemia.

19. The device of claim 11 wherein the controller is programmed to operate in the vulnerable region loading mode according to a defined schedule where operation in the vulnerable region loading mode is permitted only if the sensed variable indicates the absence of myocardial ischemia.

20. The device of claim 11 further comprising a patient-actuated switch and wherein the controller is programmed to switch to the vulnerable region unloading mode if the patient-actuated switch is actuated.