Abstract: An optical fibre assembly (10) disposed within a catheter (12) for ablating mammalian, such as heart tissue. The optical fibre assembly has a plurality of optical cores (16A-16C), each core defining a leading end and a trailing end and being adapted to carry an optical imaging beam. An optical lens arrangement (25) is operatively connected to the leading end of the plurality of optical cores for causing divergence of the light beams emitted therefrom. The optical fibre assembly (10) creates a field of view by directing a plurality of said optical imaging beams onto a tissue portion and capturing a reflected portion of said beams. The divergence of the beams provides a greater field of view than may otherwise be provided.

Abstract: A method of ablating a tissue comprising: (i) applying ablation energy to the tissue; (ii) applying light to the tissue and capturing an optical signal reflected therefrom; and (iii) monitoring the optical signal for a change indicative of an increased risk of a steam pop occurring in the tissue.

Abstract: A catheter system for ablating a tissue portion of a body and visualising the ablation in real time, the system comprising a means for generating an optical imaging beam, a catheter including a catheter tip assembly comprising an array of first optical fibres for carrying the optical imaging beam and an ablating means, wherein the catheter tip assembly is adapted to direct said beam onto the tissue portion and capture a reflected portion of the optical imaging beam from the tissue portion. The system further includes a first switching means for switching the optical imaging beam between a plurality of the first optical fibres in the array and a means for processing the reflected portion of the optical imaging beam to account for variations in length between the first optical fibres.