Endocardial mapping system

• US 5,297,549 A
• Filed: 09/23/1992
• Issued: 03/29/1994
• Est. Priority Date: 09/23/1992
• Status: Expired due to Term

• Current Assignee: St. Jude Medical, Atrial Fibrillation Division, Inc. (Abbott Laboratories)
• Original Assignee: Endocardial Therapeutics, Inc.
• Inventors: Kagan, Jonathan, Budd, Jeffrey R., Beatty, Graydon E.
• Primary Examiner(s): SYKES, ANGELA D
• Application Number:
  US07/950,448
• Time in Patent Office: 552 Days
• Field of Search: 128/639, 128/641-642, 128/693-694, 128/734, 128/783-786, 128/419 P, 607/122-123, 607/125-128
• US Class Current: 600/374
• CPC Class Codes: A61B 2560/045 with a separable interface unit, e.g. for communication
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/0535 Impedance plethysmography for measuring blood flow A61B5/0295
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/6853 with a balloon
• CPC Class Codes: A61B 5/6858 with a distal basket, e.g. expandable basket

Abstract

An array of electrode sites are placed in a heart chamber. The shape of the chamber and the location of the electrodes is determined via impedance plethysmography. Electrical measurements taken from the electrode array and referenced to a surface contacting electrode is used to generate a three-dimensional map of electrical activity. A two-dimensional map of the electrical activity within the endocardial surface is also computed.

Claims

1. A method of mapping a volumetric electrical potential distribution of a heart chamber arising from electrical activation in a myocardium comprising the steps of:

a) positioning an electrode array within the endocardial cavity;

b) positioning a reference electrode at the interior surface of said heart chamber at a known distance from said array, said reference electrode and said array together defining an endocardine reference position;

c) measuring volume and shape of said heart chamber, and generating volume measurement data from the volume and shape measurements;

d) computing the position of said array, from said volume measurement, and from said endocardial reference position, and generating array position measurement data;

e) measuring electrical potentials on said array, and generating electrical potential measurement data from the electrical potential measurements;

f) computing the three-dimensional volumetric electrical field distribution of said heart chamber volume from a spherical harmonic series expression containing said electrical potential measurements, and said array position measurement data; and

g) displaying said volumetric electrical field distribution.

3. The method of claim 1 or claim 2 wherein said electrode array has more than twenty electrodes.

4. The method of claim 1 or claim 2 wherein said step c) comprises

c1) generating a sequence of impedance plethysmography signals on said array;

c2) measuring a resultant sequence of plethysmography signals characterizing said heart volume; and

c3) generating said volume measurement data from step c2.

2. A method of mapping a two-dimensional electrical potential distribution within a wall of a heart chamber arising from electrical activation in a myocardium comprising the steps of:

a) positioning an electrode array within the endocardial cavity;

b) positioning a reference electrode at the interior surface of said heart chamber at a known distance from said array, said reference electrode and said array together defining an endocardial reference position;

c) measuring volume and shape of said heart chamber, and generating volume measurement data from the volume and shape measurements;

d) computing the position of said array, from said volume measurement, and from said endocardial reference position, and generating array position measurement data;

e) measuring the electrical potentials on said array, and generating electrical potential measurement data from the electrical potential measurements;

f) computing a three-dimensional volumetric electrical field distribution of said heart chamber volume from a spherical harmonic series expression containing said electrical potential measurement data, and said array position measurement data;

g) defining a set of computed potential points on the wall of said heart chamber;

h) inerting an intramural electrode into said wall defining a subsurface electrode site and, generating a subsurface voltage measurement, from said subsurface electrode site;

i) computing a two-dimensional potential distribution from a center of gravity calculation from said computed potential points from step g) and from said subsurface voltage measurement from step h), and generating two-dimensional map data from the two dimensional potential distribution; and

j) displaying a two-dimensional potential distribution map from said two-dimensional map data.