DETECTING VENTRICULAR NOISE ARTIFACTS IN AN ACTIVE IMPLANTABLE MEDICAL DEVICE FOR PACING, RESYNCHRONIZATION AND/OR DEFIBRILLATION OF THE HEART

• US 20070282379A1
• Filed: 05/18/2007
• Published: 12/06/2007
• Est. Priority Date: 05/18/2006
• Status: Active Grant

• Current Assignee: Sorin CRM USA (MicroPort Scientific Corp.)
• Original Assignee: Sorin CRM SAS
• Inventors: Limousin, Marcel, Vincent, Elodie
• Granted Patent: US 8,195,293 B2
• Time in Patent Office: Days
• US Class Current: 607/4
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents

Abstract

Sensing ventricular noise artifacts in an active implantable medical device for pacing, resynchronization and/or defibrillation of the heart. This device concerns sensing heart rhythm through an endocardial electrode collecting the depolarization potentials, and detecting the myocardium contractions through an endocardial acceleration sensor. The device searches for ventricular noise artifacts (X, Y) by correlating the signals representative of successive ventricular and atrial depolarizations (P, R) with the signals representative of successive acceleration peaks (PEA I). In case of a lack of correlation, a signal of suspicion of ventricular noise is delivered, which temporarily modifies the sensing sensitivity (S) of the sensing circuit.

Claims

1. An active implantable medical device for pacing, resynchronization, cardioversion and/or defibrillation of the heart, comprising:

a means for sensing a patient'"'"'s heart rhythm, comprising at least one endocardial electrode able to collect the electrical potentials representative of myocardium depolarizations, and a sensing circuit able to analyze the collected potentials and deliver a sequence of signals that are representative of the successive cardiac depolarizations;

means for detecting myocardium contractions, comprising an endocardial acceleration sensor, and means for deter-mining at least one peak of endocardial acceleration over one given cardiac cycle and deliver a sequence of signals that are representative of successive endocardial acceleration peaks (PEA); and

means for searching for ventricular noise artifacts, further comprising means for receiving as input, and correlating together, said signals representative of the cardiac depolarizations, and said signals representative of the acceleration peaks, and means for delivering, in the case of a lack of correlation, a signal of suspicion of ventricular noise.

2. The device of claim 1, further comprising means for modifying an operating parameter of said rhythm sensing means, in response to the delivery of a signal of ventricular noise suspicion.

3. The device of claim 2, wherein said operating parameter is a sensing sensitivity threshold (S) of said sensing circuit, and the means for modifying an operating parameter comprise means for increasing that sensitivity threshold by a predetermined amount (Δ

S), in response to the delivery of a signal of ventricular noise suspicion.

4. The device of claim 2, wherein the sensing circuit further comprises a digital filter and said operating parameter is a parameter of said digital filter, and the means for modifying the operating parameter further comprises means for modifying the filter parameter towards a more restrictive filtering, in response to the delivery of a signal of ventricular noise suspicion.

5. The device of claim 2, wherein the means for modifying the operating parameter further comprises means for modifying said operating parameter for a predetermined duration, or during a predetermined number of cycles, following the delivery of the signal of ventricular noise suspicion.

6. The device of claim 1, wherein the sensing circuit provides a sequence of signals that are representative of the successive ventricular and atrial depolarizations, and the device further comprises means for analyzing said signals representative of the successive ventricular and atrial depolarizations, and wherein the means for modifying the operating parameter further comprises means for restoring the operating parameter to its previous setting in a case of suspicion of an arrhythmia.

7. The device of claim 6, wherein the means for restoring the operating parameter to its previous setting in case of suspicion of an arrhythmia further comprises means for analyzing the successive ventricular and atrial depolarizations.

8. The device of claim 7, wherein the means for restoring the operating parameter further comprises means for detecting an acceleration of the cardiac contraction peaks.

9. The device of claim 1, further comprising two distinct endocardial leads, one equipped with said endocardial electrode, the other with said sensor of endocardial acceleration.

10. The device of claim 1, wherein the delivery of a signal of ventricular noise suspicion through the means for searching for artifacts, is conditioned on the detection of a sequence of acceleration peaks that are stable in terms of amplitude and/or coupling intervals.

11. The device of claim 1, wherein the delivery of a signal of ventricular noise suspicion through the means for searching for artifacts, is conditioned by the detection of a sequence of acceleration peaks with a rate that is lower than a limiting rate representative of a threshold of tachycardia detection.

12. The device of claim 1, wherein the delivery of a signal of ventricular noise suspicion through the means for searching for artifacts, is conditioned on the detection of a sequence of depolarizations presenting short and variable successive coupling intervals.

13. The device of claim 1, wherein the acceleration sensor is a sensor able to measure acceleration level with a heart ventricle.

14. The device of claim 1, wherein the acceleration sensor is a sensor able to measure acceleration level with a heart atrium.

15. The device of claim 1, wherein the acceleration sensor is a sensor able to measure acceleration level with a blood vessel that is peripheral to the heart.

16. The device of claim 1 further comprising means for delivering a ventricular therapy in accordance with an algorithm responsive to the sequence of signals, and means for modifying said algorithm to delay delivery of said ventricular therapy in response to a suspicion of ventricular noise.

17. The device of claim 16 wherein said delay of said ventricular therapy further comprises a time period having a duration that is a function of a percentage of noisy cycles detected.