Reconstruction of a surface electrocardiogram based upon an endocardial electrogram

• US 7,979,112 B2
• Filed: 11/05/2007
• Issued: 07/12/2011
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: Sorin CRM SAS (MicroPort Scientific Corp.)
• Original Assignee: Ela Medical SAS (MicroPort Scientific Corp.)
• Inventors: Porée, Fabienne, Carrault, Guy, Kachenoura, Amar, Bourguiba, Anissa, Hernandez, Alfredo, Molin, Renzo Dal
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Stice; Paula J
• Application Number:
  US11/935,334
• Publication Number:
  US 20080114257A1
• Time in Patent Office: 1,345 Days
• Field of Search: 600/512, 600/510, 600/523, 600/509
• US Class Current: 600/509
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/327 Generation of artificial ECG signals based on measured signals, e.g. to compensate for missing leads
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: G06F 2218/22 Source localisation; Inverse modelling

Abstract

The reconstruction of a surface electrocardiogram based upon an endocardial electrogram. This method includes: (a) acquisition (10) of a plurality of endocardial electrogram signals (EGM) through a plurality of endocardial leads defined based upon endocardial electrodes; (b) calculation (12), by combining the endocardial electrogram (EGM) signals acquired at step (a), of the corresponding endocardial vectogram (VGM); (c) angular resealing (14) of the orthonormalized mark of the endocardial vectogram (VGM) with that of the surface vectocardiogram (VCG); (d) estimation (16), based upon the endocardial vectogram (VGM) calculated at step (b), of a reconstructed surface vectocardiogram (VCGreconstructed), and (e) calculation (18) of the surface electrocardiogram (ECG) corresponding to said reconstructed surface vectocardiogram (VCGreconstructed).

Claims

1. A process for processing signals representative of cardiac myocardium depolarization potentials, said signals being collected by a plurality of endocardial electrodes of an active implantable medical device including an implantable pacemaker, device for resynchronization, cardioversion and/or defibrillation, the process comprising:

a) acquiring a plurality of endocardial electrogram signals (EGM) through a plurality of leads, each lead of the plurality of leads being collected between at least a pair of endocardial electrodes selected from the plurality of endocardial electrodes;

b) calculating, through a combination of the plurality of endocardial electrogram signals (EGM) acquired at step a), a corresponding endocardial vectogram (VGM);

d) estimating, based upon the endocardial vectogram calculated at step b), a reconstructed surface vectocardiogram (VCG_{reconstructed}); and

e) reconstructing surface electrocardiogram signals (ECG) corresponding to said reconstructed surface vectocardiogram (VCG_{reconstructed}),

wherein the step d) of estimating the reconstructed surface vectocardiogram (VCG_{reconstructed}) further comprises applying a linear filtering to the endocardial vectogram calculated at step b).

2. The process of claim 1, further comprising estimating a linear filter.

3. The process of claim 2, wherein said linear filter is estimated in the sense of a Wiener filter.

4. The process of claim 1, further comprising a preliminary calibration step comprising determining parameters of said linear filtering.

5. The process of claim 4, wherein determining linear filtering parameters further comprises:

i) obtaining a set of reference data through simultaneous acquisition of endocardial electrogram signals (EGM) and surface electrocardiogram signals (ECG);

ii) calculating, through a combination of the surface electrocardiogram signals (ECG) acquired at step i), a corresponding surface vectocardiogram (VCG _real);

iii) calculating, through a combination of endocardial electrogram signals (EGM) acquired at step i), a corresponding endocardial vectogram (VGM);

iv) conducting an angular resealing of an orthonormalized mark of the endocardial vectogram (VGM) upon that of the surface vectocardiogram (VCG_real)

v) estimating, through applying linear filtering to the endocardial vectogram calculated at step iii), a reconstructed surface vectocardiogram (VCG_{reconstructed}); and

vi) adjusting the linear filtering parameters of step v) so as to minimize the deviation between the surface vectocardiogram (VCG_real) calculated at step ii) and the reconstructed surface vectocardiogram (VCG_{reconstructed}) calculated at step v).

6. The process of claim 1, wherein applying linear filtering further comprises selecting the linear filtering to be one of a time domain linear filter and a frequency domain linear filter.

7. The process of claim 1, wherein the plurality of endocardial electrodes of the active implantable medical device comprises two to four endocardial electrodes implanted to a patient.

8. Apparatus for processing signals representative of cardiac myocardium depolarization potentials, comprising:

a) means for acquiring a plurality of endocardial electrogram signals (EGM) representative of a plurality of endocardial or intravascular derivations leads ;

b) means for calculating, based on a combination of said acquired endocardial electrogram signals (EGM), a corresponding endocardial vectogram (VGM);

c) means for estimating, based upon the calculated endocardial vectogram, a reconstructed surface vectocardiogram (VCG_{reconstructed}); and

d) means for calculating surface electrocardiogram signals (ECG) corresponding to said reconstructed surface vectocardiogram (VCG_{reconstructed}),

wherein the means for estimating the reconstructed surface vectocardiogram (VCG_{reconstructed}) further comprises means for applying a linear filtering to the calculated endocardial vectogram.

9. The apparatus of claim 8, wherein said means for linear filtering further comprises means for estimating a linear filter.

10. The apparatus of claim 8, wherein the plurality of endocardial electrodes of the active implantable medical device comprises two to four endocardial electrodes implanted to a patient.

11. A process for continuous calculation of a reconstructed surface vectocardiogram (VCG_{reconstructed}) comprising:

estimating a matrix for converting a first collection of endocardial electrogram signals (EGM) to a corresponding endocardial vectogram (VGM), acquiring at least one second collection of EGM subsequent to said first collection of EGM through a plurality of endocardial or intravascular leads, defined based upon said endocardial electrodes;

applying said estimated matrix to each said at least one second collection of EGM to determine a corresponding estimated VGM,

estimating, based upon the estimated VGM, a reconstructed surface vectocardiogram (VCG_{reconstructed}); and

calculating a surface electrocardiogram signals (ECG) corresponding to said reconstructed surface vectocardiogram (VCG_{reconstructed}),

wherein said estimating step further comprises employing a linear filtering of the first collection of EGM signals.