Implantable stimulation device and method for determining atrial autocapture using PVC response

• US 6,584,354 B1
• Filed: 07/17/2001
• Issued: 06/24/2003
• Est. Priority Date: 05/14/1996
• Status: Expired due to Fees

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Endaya, Melinda, Levine, Paul A., Mann, Brian M.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US09/906,505
• Time in Patent Office: 707 Days
• Field of Search: 607/28, 607/30, 607/32
• US Class Current: 607/28
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold
• CPC Class Codes: A61N 1/3714 Atrial capture
• CPC Class Codes: A61N 1/37247 User interfaces, e.g. input or presentation means

Abstract

A pacemaker programmer and diagnostic system retrieves information stored within a pacemaker and analyzes the retrieved data in real time. The stored information can be retrieved by means of a telemetry communication link. The pacemaker automatically lengthens a post-ventricular atrial refractory period (PVARP). The pacemaker determines atrial capture threshold by generating atrial stimulation pulses while maintaining the ventricular stimulation pulse amplitude at a level known to ensure ventricular capture, and by detecting loss of atrial capture. In response to loss of atrial capture, a processor automatically triggers a premature ventricular contraction (PVC) response to prevent a retrograde P-wave from initiating a pacemaker-mediated tachycardia. Also in response to loss of atrial capture, the processor sets the atrial stimulation pulse amplitude to a value above the atrial capture threshold in a subsequent cardiac cycle, and restores the PVARP to its pre-test value.

Claims

1. A method of determining atrial capture threshold utilizing a programmer in telemetric communication with a dual chamber cardiac stimulation device, the programmer adapted to interrogate and provide operational commands to the stimulation device and retrieving and analyzing diagnostic data therefrom, the method comprising the steps of:

interrogating the cardiac stimulation device to obtain an initial value for an atrial stimulation pulse amplitude;

providing a command to cause the stimulation device to adjust the atrial stimulation pulse amplitude to said initial value;

lengthening the post ventricular refractory period (PVARP) from an initial value to a first value;

delivering an atrial stimulation pulse;

detecting loss of capture and in the event of capture, decreasing the atrial stimulation pulse amplitude and repeating the detecting step until loss of capture occurs; and

recording the atrial capture threshold as being the atrial pulse amplitude below which capture is lost.

2. The method of claim 1 further comprising the step of restoring PVARP to its initial value.

3. The method of claim 1 further comprising the steps of:

retrieving historical diagnostic data from the stimulation device;

estimating an atrial stimulation pulse amplitude, from the historical data, at which loss of capture would occur; and

determining an initial atrial stimulation pulse amplitude based upon the estimated atrial pulse amplitude.

4. The method of claim 3 further comprising the step of:

adjusting the initial amplitude of the atrial stimulation pulse to a predetermined level above the estimated atrial stimulation pulse amplitude.

5. The method of claim 4 further comprising the step of:

adjusting the initial amplitude of the atrial stimulation pulse to an amplitude step immediately above the estimated atrial stimulation pulse amplitude.

6. The method of claim 1 further comprising the step of:

shortening the AV-delay to reduce the possibility of a retrograde P-wave initiating a pacemaker mediated tachycardia.

7. The method of claim 1 further comprising the step of:

subsequent to the loss of capture, restoring the atrial stimulation pulse amplitude to an initial value.

8. The method of claim 7 wherein the restoring step comprises restoring the atrial stimulation pulse to a value above the atrial capture threshold.

9. The method of claim 7 wherein the restoring step comprises restoring the atrial stimulation pulse to a value within a safety margin from the atrial capture threshold.

10. The method of claim 7, 8 or 9 further comprising the step of:

delivering an atrial stimulation pulse at a restored value.

11. The method of claim 10 further comprising the step of:

initiating a premature ventricular contraction (PVC) response to prevent a retrograde P-wave from starting a pacemaker mediated tachycardia.

12. The method of claim 1 further comprising the step of:

maintaining ventricular pulses at a level known to ensure capture in the ventricle.

13. The method of claim 1, wherein responsive to the loss of capture, the further step of delivering an atrial backup stimulation pulse concurrently with a ventricular stimulation pulse to minimize the possibility of a retrograde P-wave initiating a pacemaker mediated tachycardia.

14. The method of claim 13 further comprising the step of:

restoring PVARP and the AV-delay to respective initial values.

15. The method of claim 1 wherein the step of detecting further comprises the steps of:

providing ECG signals to the programmer, generating marker channels indicative of cardiac activity; and

comparing the ECG signals and marker channels to detect atrial capture.

16. A programmer adapted for telemetric communication with a dual chamber cardiac stimulation device, the stimulation device adapted for delivering atrial and ventricular stimulation pulses to a heart, the programmer comprising:

means for interrogating the stimulation device for obtaining and analyzing diagnostic data therefrom;

means for displaying said diagnostic data;

processor means for providing a command to the stimulation device to commence an atrial capture threshold test;

means for analyzing said diagnostic data for determining an initial value for the atrial stimulation pulse amplitude, the analyzing means comprising means for estimating, based upon historical diagnostic data, the amplitude of the atrial stimulation pulse at which capture will be lost;

means for setting the initial value for the atrial stimulation pulse amplitude;

means for detecting loss of atrial capture, and

means for recording an atrial capture threshold as being the atrial stimulation pulse amplitude below which capture is lost.

17. The programmer of claim 16 including means for setting the initial value of the atrial stimulation pulse amplitude incrementally greater than the estimated value.

18. The programmer of claim 16 wherein the detecting means comprises means for comparing ECG signals and stimulation device marker channel signals wherein the marker channel signals comprise an A marker being representative of the occurrence of an atrial stimulation pulse and a V marker being representative of the occurrence of a ventricular stimulation pulse and an R marker being representative of the occurrence of an R-wave, and wherein loss of capture is detected when an A marker is followed by a V marker instead of an R marker or when no atrial event is detected in the ECG signal during a predetermined period following an A marker.

19. The programmer of claim 18 wherein the display means displays the ECG and marker channel signals for visual observation.

20. The programmer of claim 16 wherein the detecting means comprises means for incrementally decreasing the atrial stimulation pulse amplitude until loss of capture occurs.

21. A programmer adapted for telemetric communication with a dual chamber cardiac stimulation device, the stimulation device adapted for delivering atrial and ventricular stimulation pulses to a heart, the programmer comprising:

means for interrogating the stimulation device for obtaining and analyzing diagnostic data therefrom;

means for displaying said diagnostic data;

means for lengthening post ventricular atrial refractory period (PVARP) in the stimulation device;

processor means for providing a command to the stimulation device to commence an atrial capture threshold test;

means for detecting loss of atrial capture; and

means for recording an atrial capture threshold as being the atrial stimulation pulse amplitude below which capture is lost.

22. A programmer adapted for telemetric communication with a dual chamber cardiac stimulation device, the stimulation device adapted for delivering atrial and ventricular stimulation pulses to a heart, the programmer comprising:

means for interrogating the stimulation device for obtaining and analyzing diagnostic data therefrom;

means for displaying said diagnostic data;

processor means for providing a command to the stimulation device to commence an atrial capture threshold test;

means for detecting loss of atrial capture;

means for restoring PVARP to an initial value upon loss of capture; and

means for recording an atrial capture threshold as being the atrial stimulation pulse amplitude below which capture is lost.

23. The programmer of claim 22 comprising means for shortening an atrial ventricular (AV) delay and restoring the atrial stimulation pulse amplitude to the initial value.

24. A programmer adapted for telemetric communication with a dual chamber cardiac stimulation device, the stimulation device adapted for delivering atrial and ventricular stimulation pulses to a heart, the programmer comprising:

means for interrogating the stimulation device for obtaining and analyzing diagnostic data therefrom;

means for displaying said diagnostic data;

processor means for providing a command to the stimulation device to commence an atrial capture threshold test;

means for detecting loss of atrial capture, the means for detecting loss of atrial capture comprising means for incrementally decreasing the atrial stimulation pulse amplitude until loss of atrial capture occurs;

means for recording an atrial capture threshold as being the atrial stimulation pulse amplitude below which capture is lost; and

means for delivering a backup atrial stimulation pulse concurrently with a ventricular stimulation pulse subsequent to loss of capture to minimize the possibility of a retrograde P-wave initiating a pacemaker mediated tachycardia.

25. The programmer of claim 24 comprising means for restoring the amplitude of the atrial stimulation pulse to the initial value and restoring PVARP to an initial value.

26. The programmer of claim 25 comprising means for initiating a premature ventricular contraction (PVC) response to prevent a retrograde P-wave from starting a pacemaker mediated tachycardia.

27. A programmer adapted for telemetric communication with a dual chamber cardiac stimulation device, the stimulation device adapted for delivering atrial and ventricular stimulation pulses to a heart, the programmer comprising:

means for interrogating the stimulation device for obtaining and analyzing diagnostic data therefrom;

means for analyzing the diagnostic data in real-time to thereby minimize pauses and prevent unwanted rhythms from manual or automatic capture tests;

means for displaying said diagnostic data;

processor means for providing a command to the stimulation device to commence an atrial capture threshold test;

means for detecting loss of atrial capture; and

means for recording an atrial capture threshold as being the atrial stimulation pulse amplitude below which capture is lost.

28. The programmer of claim 27 comprising means for initiating, modifying and terminating stimulation device activity by a clinician based upon the display of stimulation device data processed in real-time.

29. The programmer of claim 28 comprising means for interactively modifying stimulation device parameters during real-time processing.

30. A programmer adapted for telemetric communication with a cardiac stimulation device, the device adapted to deliver atrial and ventricular stimulation pulses to a patient'"'"'s heart, the programmer configured to determine atrial capture threshold, the programmer comprising:

a telemetry circuit adapted to provide a communication link with the stimulation device;

a controller coupled to the telemetry circuit to send and receive diagnostic data and operational commands between the programmer and stimulation device;

a processor configured to provide operational commands to the stimulation device to undertake operational functions including providing a command to commence an atrial capture threshold test;

a monitor circuit adapted to monitor loss of capture;

wherein the controller is further configured to cause the stimulation device to incrementally decrease atrial stimulation pulse amplitude until loss of capture occurs; and

wherein the processor is further configured to cause the stimulation device, in response to loss of capture, to deliver a backup atrial stimulation pulse concurrently with a ventricular stimulation pulse to thereby minimize the possibility of a retrograde P-wave initiating a “

pacemaker mediated tachycardia”

(PMT); and

a recording circuit coupled to the monitor circuit and adapted to record parametric data related to loss of capture.

31. The programmer of claim 30 wherein the processor is configured to cause the stimulation device to maintain ventricular pulses at a level known to ensure capture of the ventricle.

32. A programmer adapted for telemetric communication with a cardiac stimulation device, the device adapted to deliver atrial and ventricular stimulation pulses to a patients heart, the programmer configured to determine atrial capture threshold, the programmer comprising:

a telemetry circuit adapted to provide a communication link with the stimulation device;

a controller coupled to the telemetry circuit to send and receive diagnostic data and operational commands between the programmer and stimulation device;

a processor configured to provide operational commands to the stimulation device to undertake operational functions including providing a command to commence an atrial capture threshold test;

a monitor circuit adapted to monitor loss of capture;

wherein the processor is further configured and in response to loss of capture, to cause the stimulation device to initiate a premature ventricular contraction (PVC) response to thereby prevent a retrograde P-wave from initiating a PMT; and

a recording circuit coupled to the monitor circuit and adapted to record parametric data related to loss of capture.

33. A programmer adapted for telemetric communication with a cardiac stimulation device, the device adapted to deliver atrial and ventricular stimulation pulses to a patients heart, the programmer configured to determine atrial capture threshold, the programmer comprising:

a telemetry circuit adapted to provide a communication link with the stimulation device;

a controller coupled to the telemetry circuit to send and receive diagnostic data and operational commands between the programmer and stimulation device;

a processor configured to provide operational commands to the stimulation device to undertake operational functions including providing a command to commence an atrial capture threshold test;

wherein the processor is configured to cause the stimulation device to lengthen the post ventricular atrial refractory period (PVARP) from an initial value to a first value prior to the atrial capture threshold test and restore PVARP to the initial value subsequent to such test;

a monitor circuit adapted to monitor loss of capture; and

a recording circuit coupled to the monitor circuit and adapted to record parametric data related to loss of capture.

34. A programmer adapted for telemetric communication with a cardiac stimulation device, the device adapted to deliver atrial and ventricular stimulation pulses to a patients heart, the programmer configured to determine atrial capture threshold, the programmer comprising:

a telemetry circuit adapted to provide a communication link with the stimulation device;

a controller coupled to the telemetry circuit to send and receive diagnostic data and operational commands between the programmer and stimulation device;

a processor configured to provide operational commands to the stimulation device to undertake operational functions including providing a command to commence an atrial capture threshold test;

wherein the processor is configured to cause the stimulation device to lengthen the atrial ventricular (AV) delay from an initial value prior to the atrial capture threshold test and restoring the AV delay to the initial value subsequent to such test;

a monitor circuit adapted to monitor loss of capture; and

a recording circuit coupled to the monitor circuit and adapted to record parametric data related to loss of capture.

35. A programmer adapted for telemetric communication with a cardiac stimulation device, the device adapted to deliver atrial and ventricular stimulation pulses to a patients heart, the programmer configured to determine atrial capture threshold, the programmer comprising:

a telemetry circuit adapted to provide a communication link with the stimulation device;

a controller coupled to the telemetry circuit to send and receive diagnostic data and operational commands between the programmer and stimulation device;

an analyzer circuit coupled to the controller and adapted to analyze and process diagnostic data received from the stimulation device, in real-time;

a processor configured to provide operational commands to the stimulation device to undertake operational functions including providing a command to commence an atrial capture threshold test;

a monitor circuit adapted to monitor loss of capture;

wherein the analyzer is further adapted to determine an estimated value for the atrial stimulation pulse amplitude based upon historical diagnostic data relating to the amplitude of the atrial stimulation pulse amplitude at which capture was lost and wherein the initial value of the atrial stimulation pulse amplitude is set incrementally greater than said estimated value; and

a recording circuit coupled to the monitor circuit and adapted to record parametric data related to loss of capture.

36. A diagnostic system for determining atrial capture threshold comprising:

a programmer adapted for telemetric communication with a cardiac stimulation device;

a cardiac stimulation device adapted to deliver atrial and ventricular stimulation pulses upon command from the programmer;

a communication link telemetrically joining the programmer and the stimulation device and adapted to provide transfer of operational commands and diagnostic data between the programmer and stimulation device, the programmer comprising;

an analyzer circuit configured to analyze and process transferred diagnostic data in real-time;

a processor configured to cause the stimulation device to commence an atrial capture threshold test while maintaining ventricular pulses at a level known to ensure capture in the ventricle;

wherein the analyzer circuit is configured to estimate, from diagnostic data, an atrial stimulation pulse amplitude at which loss of capture would occur and wherein the initial amplitude of the atrial stimulation pulse is set incrementally greater than the estimated value; and

a recording circuit coupled to the processor adapted to record the atrial capture threshold as being the atrial stimulation pulse amplitude below which capture is lost.

37. The system of claim 36 wherein the processor causes the stimulation device to adjust the atrial stimulation pulse amplitude to the initial value and to commence the atrial capture threshold test.

38. The system of claim 37 wherein the processor is configured to detect loss of capture and in the event of capture the atrial stimulation pulse amplitude is incrementally decreased until loss of capture occurs, wherein the atrial capture threshold is determined as being the atrial pulse amplitude below which capture is lost.

39. A programmer adapted for telemetric communication with a dual chamber cardiac stimulation device, the stimulation device adapted for delivering atrial and ventricular stimulation pulses to a heart, the programmer comprising:

means for interrogating the stimulation device for obtaining and analyzing diagnostic data therefrom;

means for displaying said diagnostic data;

processor means for providing a command to the stimulation device to commence an atrial capture threshold test, the atrial capture threshold test comprising;

means for detecting loss of atrial capture;

means for recording an atrial capture threshold as being the atrial stimulation pulse amplitude below which capture is lost; and

means for maintaining ventricular pulses at a level known to ensure capture in a ventricle of the heart.

40. The programmer of claim 39 comprising means for setting an initial value for an atrial stimulation pulse amplitude.

41. The programmer of claim 40 comprising means for analyzing obtained diagnostic data for determining the initial value for the atrial stimulation pulse amplitude.

42. A programmer adapted for telemetric communication with a cardiac stimulation device, the device adapted to deliver atrial and ventricular stimulation pulses to a patient'"'"'s heart, the programmer configured to determine atrial capture threshold, the programmer comprising:

a telemetry circuit adapted to provide a communication link with the stimulation device;

a controller coupled to the telemetry circuit to send and receive diagnostic data and operational commands between the programmer and stimulation device;

a processor configured to provide operational commands to the stimulation device to undertake operational functions including providing a command to commence an atrial capture threshold test, the atrial capture threshold test comprising;

a monitor circuit adapted to monitor loss of capture; and

a recording circuit coupled to the monitor circuit and adapted to record parametric data related to loss of capture;

wherein the processor is configured to cause the stimulation device to maintain ventricular pulses at a level known to ensure capture of the ventricle.