Basket catheter with far-field electrode
Cardiac catheterization is performed with a catheter having a basket-shaped assembly at its distal end. A plurality of spline electrodes are disposed on the splines of the assembly. The assembly is configurable in an expanded arrangement wherein the splines bow radially outwardly and in a collapsed arrangement, wherein the splines are arranged generally along the longitudinal axis of the catheter body. A far-field electrode is disposed in the interior of the assembly. An intracardiac electrogram and a far-field electrogram are obtained with at least one of the spline electrodes and the far-field electrode, respectively. The far-field component is removed from the intracardiac electrogram using the far-field electrogram.
1. A method, comprising the steps of:
inserting a catheter into a heart of a subject, the catheter having an elongated catheter body, the catheter body having an interior, proximal end, a distal end and at least one lumen therethrough and having a basket-shaped assembly at the distal end of the catheter body, the basket-shaped assembly having a longitudinal axis, a proximal extremity and a distal extremity and comprising a plurality of splines connected at the proximal extremity and the distal extremity, the splines comprising a plurality of spline electrodes, the basket-shaped assembly configurable in an expanded arrangement wherein the splines bow radially outwardly and in a collapsed arrangement, wherein the splines are arranged generally along the longitudinal axis of the catheter body, the catheter having a far-field electrode disposed in the interior of the expanded basket-shaped assembly;
expanding the basket-shaped assembly to contact at least one of the spline electrodes with a surface of the heart;
thereafter receiving an intracardiac electrogram with the at least one of the spline electrodes and receiving a far-field electrogram with the far-field electrode, the intracardiac electrogram having a near-field component and a far-field component;
removing the far-field component from the intracardiac electrogram while retaining the near-field component by applying the far-field electrogram to the intracardiac electrogram to generate a modified intracardiac electrogram; and
reporting the modified intracardiac electrogram.
2. The method according to claim 1 , wherein removing the far-field component comprises subtracting the far-field electrogram from the intracardiac electrogram.
3. The method according to claim 1 , the basket-shaped assembly further comprising a distal electrode location sensor mounted at or distal to the distal extremity of the basket-shaped assembly, and a proximal electrode location sensor mounted at or proximal to the proximal extremity of the basket-shaped assembly, the method further comprising the steps of:
determining coordinates of the distal electrode location sensor relative to those of the proximal electrode location sensor; and
using the coordinates together with known information pertaining to curvature of the splines of the basket-shaped assembly to determine locations of each of the spline electrodes.