METHOD, DEVICE, IMPLANTABLE STIMULATOR AND DUAL CHAMBER CARDIAC THERAPY SYSTEM

• US 20100305640A1
• Filed: 10/31/2006
• Published: 12/02/2010
• Est. Priority Date: 10/31/2006
• Status: Active Grant

• Current Assignee: St. Jude Medical AB (Abbott Laboratories)
• Original Assignee: St. Jude Medical AB (Abbott Laboratories)
• Inventors: Björling, Anders
• Granted Patent: US 8,103,344 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3624 occurring in the atrium, i.e. atrial tachycardia
• CPC Class Codes: A61N 1/36578 controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone
• CPC Class Codes: A61N 1/3688 configured for switching the pacing mode, e.g. from AAI to DDD

Abstract

In a device and method in a dual chamber pacing system operating in an atrial synchronized mode, the cardiac stimulator is connectable to a lead arrangement arranged for sensing atrial electrical and mechanical activity. Upon detection of an atrial arrhythmia based on either of sensed atrial mechanical activity, atrial electrical activity, or a combination thereof, a mode switch from an atrial synchronized ventricle stimulating mode to a non-atrial synchronized mode is triggered.

Claims

1. A device for a dual chamber cardiac stimulator for controlling the delivery of stimulation pulses to a human heart, wherein the stimulator is connectable to a lead arrangement arranged for sensing atrial electrical activity and atrial mechanical activity, the device comprising processing circuitry configured to:

receive a first signal representative of atrial electrical activity, and a second signal representative of atrial mechanical activity;

determine if said electrical activity indicates atrial tachyarrhythmia, if said mechanical activity indicates atrial tachyarrhythmia, and if a combination of said electrical and mechanical activity indicates atrial tachyarrhythmia; and

effectuate a mode switch, as soon as either of said electrical, mechanical, or combination of electrical and mechanical activity indicates atrial tachyarrhythmia, from a first mode where delivery of ventricular stimulation pulses is synchronized to detected atrial events, to a second mode where delivery of ventricular stimulation pulses is unsynchronized to detected atrial events.

2. The device as claimed in claim 1, wherein said first signal is an atrial electrogram.

3. The device as claimed in claim 1 or 2, wherein said processing circuitry is configured to calculate from said first signal the frequency of atrial electrical activity, and compare said calculated electrical frequency with a threshold value for determining if atrial tachyarrhythmia is indicated.

4. The device as claimed in claim 1, wherein said atrial mechanical activity is representative of atrial mechanical contractions.

5. The device as claimed in claim 4, wherein said processing circuitry is configured to calculate from said second signal the frequency of mechanical activity, and compare said calculated mechanical frequency with a threshold value for determining if atrial tachyarrhythmia is indicated.

6. The device as claimed in claim 5, wherein said processing circuitry is configured to:

compare said calculated mechanical frequency with an upper threshold value, with a lower threshold value, or both, and

determine that atrial tachyarrhythmia is indicated if the calculated mechanical frequency is higher than said upper threshold value, or lower than said lower threshold value.

7. The device as claimed in claim 1, wherein the processing circuitry is configured to:

detect from said first signal atrial depolarization,

detect from said second signal atrial contraction, and

determine that atrial tachyarrhythmia is indicated if detected atrial depolarization is not followed by a resulting mechanical contraction.

8. The device as claimed in claim 1, wherein said processing circuitry is configured to:

calculate from said first signal the frequency of atrial electrical activity,

calculate from said second signal the frequency of atrial mechanical activity,

calculate a quotient between said electrical frequency and said mechanical frequency,

compare said quotient to a threshold range, and

determine that atrial tachyarrhythmia is indicated if the quotient falls outside said threshold range.

9. The device as claimed in claim 1, wherein said processing circuitry is configured to:

obtain the morphology or selected indicative features of said second signal, and evaluate said morphology or selected indicative features for determining if atrial tachyarrhythmia may be indicated.

10. The device as claimed in claim 9, wherein said processing circuitry is configured to:

evaluate, if said morphology or selected indicative features indicates that atrial tachyarrhythmia may be indicated, said first signal for determining if atrial tachyarrhythmia is indicated.

11. The device as claimed in claim 10, wherein said processing circuitry is configured to:

calculate from said first signal the frequency of atrial electrical activity, and

evaluate said first signal and determining that atrial tachyarrhythmia is present if

the frequency of atrial electrical activity exceeds a threshold value, or

the frequency of atrial electrical activity is irregular.

12. The device as claimed in claim 1, wherein said atrial mechanical activity is atrial pressure changes detected by a pressure sensor, said pressure changes being representative of atrial contraction.

13. The device as claimed on claim 12, wherein the processing circuitry is configured to determine that atrial tachyarrhythmia is indicated if the amplitude of said detected pressure changes falls below a threshold value.

14. The device as claimed in claim 1, wherein said atrial mechanical activity is atrial wall movements detected by an accelerometer, said atrial wall movements being representative of atrial contraction.

15. The device as claimed in claim 1, wherein said processing circuitry is configured to:

effectuate a mode switch from said second mode to said first mode if none of said mechanical, electrical and combination of mechanical and electrical activity indicates atrial tachyarrhythmia.

16. An implantable dual chamber cardiac stimulator for delivering dual chamber stimulation pulses to a human heart, comprising:

a pulse generator for generating said stimulation pulses;

said stimulator being connectable to a cardiac lead arrangement for conduction of stimulation pulses to the heart and sensed cardiac electrical activity from the heart, said lead arrangement further being arranged for sensing atrial electrical activity and atrial mechanical activity; and

control circuitry configured to receive a first signal representative of atrial electrical activity, and a second signal representative of atrial mechanical activity, determine if said electrical activity indicates atrial tachyarrhythmia, if said mechanical activity indicates atrial tachyarrhythmia, and if a combination of said electrical and mechanical activity indicates atrial tachyarrhythmia, and effectuate a mode switch, as soon as either of said electrical, mechanical, or combination of electrical and mechanical activity indicates atrial tachyarrhythmia, from a first mode where delivery of ventricular stimulation pulses is synchronized to detected atrial events, to a second mode where delivery of ventricular stimulation pulses is unsynchronized to detected atrial events.

17. A dual chamber cardiac therapy system for delivering stimulation pulses to a human heart, comprising:

a pulse generator for generating said stimulation pulses;

control circuitry configured to receive a first signal representative of atrial electrical activity, and a second signal representative of atrial mechanical activity, determine if said electrical activity indicates atrial tachyarrhythmia, if said mechanical activity indicates atrial tachyarrhythmia, and if a combination of said electrical and mechanical activity indicates atrial tachyarrhythmia, and effectuate a mode switch, as soon as either of said electrical, mechanical, or combination of electrical and mechanical activity indicates atrial tachyarrhythmia, from a first mode where delivery of ventricular stimulation pulses is synchronized to detected atrial events, to a second mode where delivery of ventricular stimulation pulses is unsynchronized to detected atrial events; and

a cardiac lead arrangement for conducting said stimulation pulses to the heart, and for conducting electrical signals from the heart to the control circuitry, said lead arrangement comprising an implantable lead arranged for sensing atrial electrical activity and atrial mechanical activity.

18. The system as claimed in claim 17, wherein the lead arrangement comprises a mechanical sensor for sensing said atrial mechanical activity.

19. The system as claimed in claim 18, wherein said mechanical sensor is a pressure sensor arranged for positioning in or at an atrium of the heart.

20. The system as claimed in claim 19, wherein said mechanical sensor is an accelerometer.

21. A method for detecting an atrial arrhythmia for activating a pacing mode switch in a dual chamber cardiac stimulator, comprising the steps of:

receiving a first signal representative of atrial electrical activity, and a second signal representative of atrial mechanical activity;

determining if said electrical activity indicates atrial tachyarrhythmia;

if said mechanical activity indicates atrial tachyarrhythmia, and if a combination of said electrical and mechanical activity indicates atrial tachyarrhythmia; and

effectuating a mode switch, as soon as either of said electrical, mechanical, or combination of electrical and mechanical activity indicates atrial tachyarrhythmia, from a first mode where delivery of ventricular stimulation pulses is synchronized to detected atrial events, to a second mode where delivery of ventricular stimulation pulses is unsynchronized to detected atrial events.

22. The method as claimed in claim 21 wherein said first signal is an atrial electrogram.

23. The method as claimed in claim 21, further comprising the steps of

calculating from said first signal the frequency of atrial electrical activity, and

comparing said calculated electrical frequency with a threshold value for determining if atrial tachyarrhythmia is indicated.

24. The method as claimed in claim 21, wherein said atrial mechanical activity is representative of atrial mechanical contractions.

25. The method as claimed in claim 24, further comprising the steps of

calculating from said second signal the frequency of mechanical activity, and

comparing said calculated mechanical frequency with a threshold value for determining if atrial tachyarrhythmia is indicated.

26. The method as claimed in claim 25, further comprising the steps of

comparing said calculated mechanical frequency with an upper threshold value, with a lower threshold value, or both, and

determining that atrial tachyarrhythmia is indicated if the calculated mechanical frequency is higher than said upper threshold value, or lower than said lower threshold value.

27. The method as claimed in claim 21, further comprising the steps of

detecting from said first signal atrial depolarization,

detecting from said second signal atrial contraction, and

determining that atrial tachyarrhythmia is indicated if detected atrial depolarization is not followed by a resulting mechanical contraction.

28. The method as claimed in claim 21, further comprising the steps of

calculating from said first signal the frequency of atrial electrical activity,

calculating from said second signal the frequency of atrial mechanical activity,

calculating a quotient between said electrical frequency and said mechanical frequency,

comparing said quotient to a threshold range, and

determining that atrial tachyarrhythmia is indicated if the quotient falls outside said threshold range.

29. The method as claimed in claim 21, further comprising the steps of

obtaining the morphology or selected indicative features of said second signal, and

evaluating said morphology or selected indicative features for determining if atrial tachyarrhythmia may be indicated.

30. The method as claimed in claim 29, further comprising the step of evaluating, if said morphology or selected indicative features indicates that atrial tachyarrhythmia may be indicated, said first signal for determining if atrial tachyarrhythmia is indicated.

31. The method as claimed in claim 30, further comprising the steps of

calculating from said first signal the frequency of atrial electrical activity, and

evaluating said first signal and determining that atrial tachyarrhythmia is present if

the frequency of atrial electrical activity exceeds a threshold value, or

the frequency of atrial electrical activity is irregular.

32. The method as claimed in claim 21, wherein said atrial mechanical activity is atrial pressure changes detected by a pressure sensor, said pressure changes being representative of atrial contraction.

33. The method as claimed in claim 32, comprising the step of determining that atrial tachyarrhythmia is indicated if the amplitude of said detected pressure changes falls below a threshold value.

34. The method as claimed in claim 21, wherein said atrial mechanical activity is atrial wall movements detected by an accelerometer, said atrial wall movements being representative of atrial contraction.

35. The method as claimed in claim 21, further comprising the step of

effectuating a mode switch from said second mode to said first mode if none of said mechanical, electrical and combination of mechanical and electrical activity indicates atrial tachyarrhythmia.

36. (canceled)

37. a compute-readable medium encoded with programming instructions loadable into an internal memory of a dual chamber cardiac stimulator for operating a processor in control circuitry of the stimulator to control delivery of stimulation pulses to a human heart, the stimulator being connectable to a lead arrangement and arranged for sensing atrial electrical activity and atrial mechanical activity, said programming instructions causing said processor to operate said control circuitry to:

receive a first signal representative of atrial electrical activity, and a second signal representative of atrial mechanical activity;

determine if said electrical activity indicates atrial tachyarrhythmia, if said mechanical activity indicates atrial tachyarrhythmia, and if a combination of said electrical and mechanical activity indicates atrial tachyarrhythmia; and

effectuate a mode switch, as soon as either of said electrical, mechanical, or combination of electrical and mechanical activity indicates atrial tachyarrhythmia, from a first mode where delivery of ventricular stimulation pulses is synchronized to detected atrial events, to a second mode where delivery of ventricular stimulation pulses is unsynchronized to detected atrial events.