| abstract |
A method and apparatus for identifying the fossa ovalis. The transseptal apparatus (50) includes a hollow sheath (51) and an internal catheter (52). The distal end (70) of the catheter (52) includes first and second electrodes (65, 66) that communicate with cables (53, 54) which may be attached to a device for generating electrograms. The electrograms are acquired while moving the electrodes to a plurality of positions against the interatrial septum. The fossa ovalis is identified on the basis of at least one of unipolar voltage reduction, signal fractionation, broadened signal, reduced signal slew rate, reduced local myocardial impedance, increased phase angle, and increased pacing threshold. |