Patent ID: 8876817

Claim:
An electrophysiology system comprising: an ablation catheter including: a flexible catheter body having a distal portion; a tissue ablation electrode configured to apply ablation energy to the myocardial tissue; a plurality of microelectrodes circumferentially distributed about the tissue ablation electrode and electrically isolated therefrom, the plurality of microelectrodes defining a plurality of bipolar microelectrode pairs, each bipolar microelectrode pair configured to generate an output signal based on a cardiac activation signal; a radiofrequency (RF) generator operatively coupled to the tissue ablation electrode for generating the ablation energy to be conveyed to the tissue ablation electrode; and a mapping processor configured to: acquire the output signals from each of the bipolar microelectrode pairs; compare an amplitude of the output signal from each of the bipolar microelectrode pairs to the amplitudes of the output signals from the other of the plurality of bipolar microelectrode pairs; and generate an output to a display to provide a clinician with a visual indication of a proximity of the tissue ablation electrode to the myocardial tissue, the visual indication including: an indication that the tissue ablation electrode is in contact with the myocardial tissue if, based on the comparison between the amplitudes of the output signals, a difference between the amplitude of any one of the output signals and the amplitude of any one or more of the other output signals exceeds a predetermined threshold; and an indication that the tissue ablation electrode is not in contact with the myocardial tissue if, based on the comparison between the amplitudes of the output signals, the difference between the amplitude of any one of the output signals and the amplitude of any one or more of the other output signals does not exceed a predetermined threshold.