Method and apparatus for optimizing cardiac pumping performance

• US 20040019365A1
• Filed: 07/26/2002
• Published: 01/29/2004
• Est. Priority Date: 07/26/2002
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Yu, Yinghong, Zhu, Qingsheng, Ding, Jiang
• Granted Patent: US 7,206,634 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay
• 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 cardiac rhythm and function management device configured to automatically adjust stimulation parameters used in delivering cardiac resynchronization therapy. Mechanical contraction intervals are measured using appropriately placed accelerometers and compared with optimum values. The stimulation parameters can then be adjusted accordingly in a manner that moves the mechanical contraction intervals toward their optimum values.

Claims

1. A cardiac device, comprising:

a first stimulation channel configurable for stimulating the right or left ventricle;

a controller for controlling the delivery of stimulus pulses through the stimulation channels in accordance with a programmed mode;

right and left ventricular accelerometers configurable for sensing mechanical contraction of the right ventricular septal wall and left ventricular free wall, respectively; and

wherein the controller is programmed to measure the time interval between contractions of the right ventricular septal wall and left ventricular free wall as sensed by the accelerometers during a cardiac cycle.

2. The device of claim 1 further comprising right and left ventricular sensing channels configurable for sensing electrical activity in the right and left ventricles, respectively, and wherein the controller is programmed to stimulate one ventricle at a biventricular offset interval with respect to a sense from the contralateral ventricle, and further wherein controller is programmed to adjust the biventricular offset interval until the measured interval between contractions of the right ventricular septal wall and left ventricular free wall approximately equals a specified value T2.

3. The device of claim 2 further comprising a second stimulation channel configurable for stimulating the right or left ventricle and wherein the controller is programmed to stimulate one ventricle at the biventricular offset interval with respect to either a sense or stimulation of the contralateral ventricle, and further wherein controller is programmed to adjust the biventricular offset interval until the measured interval between contractions of the right ventricular septal wall and left ventricular free wall approximately equals a specified value T2.

4. The device of claim 3 wherein the specified value T2 is approximately zero, representing simultaneous contraction of the right ventricular septal wall and left ventricular free wall.

5. The device of claim 3 wherein the biventricular offset interval may be positive, negative, or zero.

6. The device of claim 3 further comprising:

an atrial sensing channel configurable for sensing electrical activity in an atrium;

a left atrial accelerometer configurable for sensing mechanical contraction of the left atrium; and

,

wherein the controller is programmed to measure the time interval between contractions of the left atrium and the left ventricle as sensed by the accelerometers during a cardiac cycle.

7. The device of claim 6 wherein the controller is programmed to stimulate the right or left ventricle in an atrial tracking mode with a specified atrio-ventricular interval between an atrial sense and a ventricular stimulus and wherein the controller is further programmed to adjust the atrio-ventricular interval until the measured time interval between contractions of the left atrium and left ventricle approximately equals a specified value T1.

8. The device of claim 7 wherein the controller is programmed to stimulate the right or left ventricle at a biventricular offset interval with respect to the stimulation of the contralateral ventricle, and further wherein the controller is programmed to adjust the biventricular offset interval until the measured interval between contractions of the right ventricular septal wall and left ventricular free wall approximately equals a specified value T2.

9. The device of claim 7 further comprising an atrial stimulation channel and wherein the controller is programmed to pace an atrium such that an atrial stimulus and a ventricular stimulus are separated by the specified atrio-ventricular interval.

10. A method for operating a cardiac device, comprising:

delivering stimulus pulses to the right or left ventricle in accordance with a programmed mode;

sensing mechanical contraction of the right ventricular septal wall and left ventricular free wall; and

measuring the time interval between contractions of the right ventricular septal wall and left ventricular free wall during a cardiac cycle.

11. The method of claim 10 further comprising:

sensing electrical activity in the right and left ventricles;

stimulating one ventricle at a biventricular offset interval with respect to a sense from the contralateral ventricle; and

,

adjusting the biventricular offset interval until the measured interval between contractions of the right ventricular septal wall and left ventricular free wall approximately equals a specified value T2.

12. The method of claim 11 further comprising stimulating both ventricles, wherein one ventricle is stimulated at the biventricular offset interval with respect to either a sense or stimulation of the contralateral ventricle.

13. The method of claim 11 wherein the specified value T2 is approximately zero, representing simultaneous contraction of the right and left ventricles.

14. The method of claim 12 wherein the biventricular offset interval may be positive, negative, or zero.

15. The method of claim 12 further comprising:

sensing electrical activity in an atrium;

sensing mechanical contraction of the left atrium; and

,

measuring the time interval between contractions of the left atrium and the left ventricle as sensed by the accelerometers during a cardiac cycle.

16. The method of claim 15 further comprising:

stimulating the right or left ventricle in an atrial tracking mode with a specified atrio-ventricular interval between an atrial sense and a ventricular stimulus; and

,

adjusting the atrio-ventricular interval until the measured time interval between contractions of the left atrium and left ventricle approximately equals a specified value T1.

17. The method of claim 16 further comprising:

stimulating the right or left ventricle at a biventricular offset interval with respect to the stimulation of the contralateral ventricle; and

,

adjusting the biventricular offset interval until the measured interval between contractions of the right ventricular septal wall and left ventricular free wall approximately equals a specified value T2.

18. The method of claim 16 further comprising pacing an atrium such that an atrial stimulus and a ventricular stimulus are separated by the specified atrio-ventricular interval.