Data manipulation following delivery of a cardiac stimulus in an implantable cardiac stimulus device

• US 9,242,112 B2
• Filed: 02/20/2014
• Issued: 01/26/2016
• Est. Priority Date: 01/18/2008
• Status: Active Grant

• Current Assignee: Cameron Incorporated (Schlumberger NV)
• Original Assignee: Cameron Incorporated (Schlumberger NV)
• Inventors: Palreddy, Surekha, Allavatam, Venugopal
• Primary Examiner(s): Holmes, Rex R
• Application Number:
  US14/184,758
• Publication Number:
  US 20140172032A1
• Time in Patent Office: 705 Days
• Field of Search: 607/4, 607/5, 607/9, 607/17, 600/509, 600/510, 600515-518
• US Class Current: 1/1
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats
• CPC Class Codes: A61N 1/0504 Subcutaneous electrodes
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 1/3925 Monitoring; Protecting
• CPC Class Codes: A61N 1/3943 for threshold determination
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock

Abstract

Methods of cardiac rhythm analysis in an implantable cardiac stimulus device, and devices configured for such methods. In an illustrative embodiment, certain data relating to cardiac event rate or amplitude is modified following delivery of a cardiac stimulus. In another embodiment, cardiac rhythm analysis is performed using one of plural states, with the plural states using different criteria, such as a detection threshold, to detect cardiac events in a sensed signal. Following delivery of a cardiac stimulus, data is manipulated to force the analysis into one of the states, where stimulus is delivered, in the illustrative embodiment, only after a different state is invoked. Implantable devices incorporating operational circuitry for performing such methods are also included in other illustrative embodiments.

Claims

1. A method of cardiac signal analysis in an implantable cardiac stimulus device (ICSD) having electrodes adapted for implantation into a patient'"'"'s body and operational circuitry contained in a housing coupled to the electrodes, the method comprising:

the ICSD delivering cardiac stimulus;

following the delivery of stimulus, the operational circuitry capturing a cardiac signal from the electrodes;

the operational circuitry identifying a cardiac event in the captured cardiac signal by comparing the captured cardiac signal to an amplitude threshold, the amplitude threshold being defined;

by a first shape when the ICSD is in a first state; and

by a second shape different from the first shape when the ICSD is in a second state; and

wherein;

when in the second state, the ICSD can determine that cardiac stimulus is indicated;

when in the first state, the ICSD cannot determine that cardiac stimulus is indicated;

the ICSD is configured to automatically set itself to the first state without reference to the captured cardiac signal following the delivery of cardiac stimulus and detect at least one detected event while in the first state; and

the method further comprises the operational circuitry storing data related to the detected event including a rate calculation, and wherein the operational circuitry is also configured to modify at least some rate calculation data in the stored data following delivery of a cardiac stimulus, without reference to the captured cardiac signal.

2. The method of claim 1 wherein the patient'"'"'s cardiac rate is used in determining which of the first state and the second state the ICSD should use, with the first state being used when the patient'"'"'s cardiac rate is at relatively lower levels and the second state being used when the patient'"'"'s cardiac rate is at relatively higher levels.

3. The method of claim 1 wherein the operational circuitry is configured such that the detected event is intended to represent a single cardiac cycle.

4. An implantable cardiac stimulus device (ICSD) comprising operational circuitry coupled to a plurality of electrodes such that:

the operational circuitry can capture cardiac event data using a selected plurality of at least two electrodes when the ICSD is implanted in a patient; and

the operational circuitry can deliver cardiac stimulus to a patient using a selected plurality of at least two electrodes when the ICSD is implanted in the patient;

wherein the operational circuitry is configured to identify a cardiac event in a captured cardiac signal by comparing the captured cardiac signal to an amplitude threshold, the amplitude threshold being defined;

by a first shape when the ICSD is in a first state; and

by a second shape different from the first shape when the ICSD is in a second state;

wherein the ICSD is configured to deliver stimulus to a patient and, following the delivery of stimulus, the operational circuitry is configured to automatically set the ICSD to the first state without reference to the captured cardiac signal and detect at least one detected event while in the first state;

wherein when in the second state, the operational circuitry is enabled to determine that cardiac stimulus is indicated and, when in the first state, the operational circuitry is not enabled to determine that cardiac stimulus is indicated;

wherein the operational circuitry is further configured to store data related to the detected event includes modifying a rate calculation, and

wherein the ICSD is also configured to modify at least some rate calculation data in the stored data following delivery of a cardiac stimulus, without reference to the captured cardiac signal.

5. The ICSD of claim 4 wherein the operational circuitry is configured to use the patient'"'"'s cardiac rate to determine which of the first state and the second state the ICSD should use, with the first state being used when the patient'"'"'s cardiac rate is at relatively lower levels and the second state being used when the patient'"'"'s cardiac rate is at relatively higher levels.

6. The method of claim 4 wherein the operational circuitry is configured such that the detected event is intended to represent a single cardiac cycle.

7. An implantable cardiac stimulus device (ICSD) comprising analysis means for analyzing data coupled to sensing means for sensing cardiac electrical signals;

wherein the analysis means is configured to identify a cardiac event in a sensed cardiac electrical signal by comparing the sensed cardiac electrical signal to an amplitude threshold, the amplitude threshold being defined;

by a first shape when the ICSD is in a first state; and

by a second shape different from the first shape when the ICSD is in a second state; and

wherein the ICSD is configured to deliver stimulus to a patient and, following the delivery of stimulus, the analysis means is configured to automatically set the ICSD to the first state without reference to the captured cardiac signal and identify at least one cardiac event while in the first state;

wherein, when in the second state, the analysis means is enabled to determine that cardiac stimulus is indicated and, when in the first state, the analysis means is not enabled to determine that cardiac stimulus is indicated;

further wherein;

the analysis means is further configured to store data related to the identified cardiac events and calculate and store a cardiac rate therefrom;

the analysis means is further configured to modify at least one stored cardiac rate following the delivery of a cardiac stimulus, without reference to the sensed cardiac electrical signal.

8. The ICSD of claim 7 wherein the analysis means is configured to use the patient'"'"'s cardiac rate to determine which of the first state and the second state the ICSD should use, with the first state being used when the patient'"'"'s cardiac rate is at relatively lower levels and the second state being used when the patient'"'"'s cardiac rate is at relatively higher levels.

9. The ICSD of claim 7 wherein the analysis means is configured such that the detected event is intended to represent a single cardiac cycle.