Cardiac catheterization is carried out using a catheter having anelectrode assembly disposed on the distal portion of the catheter. Theelectrode assembly includes a sensing electrode connected to a remotereceiver, and at least one grounded guard electrode spaced apart fromthe sensing electrode by a gap. The sensing electrode is bracketed on atleast two sides by the at least one grounded guard electrode. Signals arereceived from the sensing electrode in the receiver
