Device based cardiac monitoring and stress test

• US 8,868,182 B2
• Filed: 07/16/2012
• Issued: 10/21/2014
• Est. Priority Date: 07/16/2012
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Song, Zhendong, Zhou, Xiaohong
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US13/549,983
• Publication Number:
  US 20140018688A1
• Time in Patent Office: 827 Days
• Field of Search: None
• US Class Current: 607/9
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor

Abstract

A medical device and associated method establish an occurrence of a premature atrial contraction. The device senses a ventricular signal. A control unit is configured to determine a metric of the ventricular signal during an interval following the premature atrial contraction and detect a change in cardiac stress tolerance in response to the determined metric.

Claims

1. A method for detecting change in cardiac stress tolerance in a medical device, comprising:

establishing an occurrence of a premature atrial contraction;

sensing a ventricular signal comprising an S-T segment subsequent to the established occurrence;

determining a metric of the ventricular signal S-T segment during an interval following the premature atrial contraction; and

detecting a change in cardiac stress tolerance in response to the determined metric.

2. The method of claim 1, wherein establishing an occurrence of the premature atrial contraction comprises sensing an intrinsic premature atrial contraction.

3. The method of claim 1, wherein establishing an occurrence of the premature atrial contraction comprises delivering a premature atrial pacing pulse.

4. The method of claim 3, wherein delivering the premature atrial pacing pulse comprises delivering a run of premature atrial pacing pulses.

5. The method of claim 1, wherein the metric of the ventricular signal ST segment is a change in ST segment amplitude.

6. A method for detecting change in cardiac stress tolerance in a medical device, comprising:

establishing an occurrence of a premature atrial contraction by delivering a run of premature atrial pacing pulses;

sensing a ventricular signal subsequent to the established occurrence;

determining a metric of the ventricular signal during an interval following the premature atrial contraction;

adjusting a pacing control parameter controlling the run of premature atrial pacing pulses to cause increasing cardiac stress during the run;

determining a trend of the metric over the run; and

detecting a change in stress tolerance in response to the trend.

7. The method of claim 6, wherein adjusting the pacing control parameter comprises decreasing a pacing interval within the run.

8. The method of claim 7, further comprising detecting a decrease in stress tolerance in response to detecting a change in the metric at a relatively shorter pacing interval than a previously detected change.

9. The method of claim 6, further comprising

determining a number of premature atrial pacing pulses in the run required to cause a change in the metric;

and

detecting the change in the stress tolerance in response to determining the number.

10. The method of claim 6, wherein the ventricular signal comprises one of an EGM signal, an ECG signal, a pressure signal, a heart sound signal, an oxygen saturation signal, and an accelerometer signal.

11. The method of claim 6, further comprising:

varying a pacing interval during the run of premature atrial pacing pulses;

computing the metric of the ventricular signal for each of the premature atrial pacing pulses;

establishing a relationship between the varied pacing interval and the metric; and

selecting a pacing interval for inducing a premature atrial pacing pulse in response to the established relationship,

wherein establishing the time of the premature atrial contraction comprises delivering a premature atrial pacing pulse at the selected pacing interval.

12. A medical device, comprising:

a sensing module for sensing an atrial signal and a ventricular signal comprising an ST segment; and

a control unit configured to establish an occurrence of a premature atrial contraction, determine a metric of the ventricular signal ST segment during an interval following the premature atrial contraction, and determine a change in cardiac stress tolerance in response to the determined metric.

13. The device of claim 12, wherein establishing the occurrence of the premature atrial contraction comprises sensing an intrinsic premature atrial contraction from the atrial signal.

14. The device of claim 12, further comprising a pulse generator,

wherein establishing the occurrence of the premature atrial contraction comprises controlling the pulse generator to deliver a premature atrial pacing pulse.

15. The device of claim 14, wherein delivering the premature atrial pacing pulse comprises delivering a run of premature atrial pacing pulses.

16. A medical device, comprising:

a sensing module for sensing an atrial signal and a ventricular signal;

a pulse generator; and

a control unit configured to;

establish an occurrence of a premature atrial contraction by controlling the pulse generator to deliver a run of premature atrial pacing pulses,

adjust a pacing control parameter controlling the run of premature atrial pacing pulses to cause increasing cardiac stress during the run,

determine a metric of the ventricular signal during an interval following the premature atrial contraction,

determine a trend of the metric over the run, and

detect a change in stress tolerance in response to the trend.

17. The device of claim 16, wherein adjusting the pacing control parameter comprises adjusting a pacing interval within the run.

18. The device of claim 17, wherein the control unit is configured to detect a decrease in stress tolerance in response to detecting a change in the metric at a relatively longer pacing interval than a previously detected change.

19. The device of claim 16, wherein the control unit is configured to:

determine a number of premature atrial pacing pulses in the run required to cause a change in the metric; and

detect the change in the stress tolerance in response to determining the number.

20. The device of claim 16, wherein the ventricular signal comprises one of an EGM signal, and ECG signal, a pressure signal, a heart sound signal, an oxygen saturation signal, and an accelerometer signal.

21. The device of claim 16, further comprising,

the control unit configured to:

control the pulse generator to vary a pacing interval during the run of premature atrial pacing pulses,

compute the metric of the ventricular signal for each of the premature atrial pacing pulses,

establish a relationship between the varied pacing interval and the metric, and

select a pacing interval for inducing a premature atrial pacing pulse in response to the established relationship, wherein establishing the time of the premature atrial contraction comprises controlling the pulse generator to deliver a premature atrial pacing pulse at the selected pacing interval.

22. A non-transitory computer-readable medium comprising instructions for causing a processor of a medical device system to perform a method, the method comprising:

establishing an occurrence of a premature atrial contraction;

sensing a ventricular signal comprising an ST segment subsequent to the established occurrence;

determining a metric of the ventricular signal ST segment during an interval following the premature atrial contraction; and

detecting a change in cardiac stress tolerance in response to the determined metric.