Patent ID: 7211082

Claim:
A method of mapping the electrical characteristics of the left atrium of the heart comprising: providing a magnetically navigable electrode catheter comprising a sleeve having a proximal end and a distal end, an extension member having a proximal end and a distal end, the extension member being slidably mounted in the sleeve so that the distal end portion telescopes from the distal end of the sleeve, the distal end portion of the extension member being relatively more flexible than the distal end of the sleeve; providing at least one electrode on the distal end of the extension member; and at least one magnet on the distal end of portion of the extension member, wherein the distal end portion of the extension member containing the at least one magnet is relatively rigid and the portion of the extension member just proximal to the at least one magnet is flexible; introducing the distal end of the magnetically navigable electrode catheter into left atrium; moving the electrode into contact with a selected point on the surface of the left atrium by applying an external magnetic field, such that the catheter bends at a point proximal to the distal end portion having the at least one magnet, and selectively telescoping extension member relative to the sleeve to bring the electrode on the distal end of the extension member into contact with the specific point on the surface of the left atrium; measuring the electrical characteristics of the left atrium between the electrodes.