Patent Document ID: 20140051959
Application ID: 13589347
Patent Flag: 0

Claim One:
1. A method of cardiac catheterization, comprising the steps of: inserting a probe into a heart of a living subject, the probe having an electrode; memorizing a designation of a contact state between the electrode and a wall of the heart as one of an in-contact state and an out-of-contact state; while the electrode is at the wall, passing an electrical current between the electrode of the probe and another electrode; making at least three determinations of an impedance phase angle of the electrical current; identifying a maximum phase angle and a minimum phase angle among the determinations; defining a binary classifier as a value that is intermediate the minimum phase angle and the maximum phase angle; when the designation of the contact state is the in-contact state, changing the designation to the out-of-contact state when another of the determinations is less than the binary classifier by at least a first hysteresis factor; when the designation of the contact state is the out-of-contact state, changing the designation to the in-contact state when the other of the determinations is greater than the binary classifier by at least a second hysteresis factor; and reporting the changed designation.