Patent ID: 7942871

Claim:
A cardiac ablation system comprising: a fluid source; and an ablation catheter slidably disposed in an outer catheter, the ablation catheter comprising an anchor adapted to support the ablation catheter within an atrium of a heart and an ultrasound emitter disposed radially outward from a rotation axis and from the anchor, and a control mechanism adapted to rotate the ultrasound emitter about the rotation axis and to provide ablation energy to the ultrasound emitter to ablate heart tissue, wherein the ablation catheter is axially movable relative to the outer catheter thereby allowing control of lesion depth by adjustment of distance between the ultrasound emitter relative to the heart tissue, and wherein the ultrasound emitter comprises an ultrasound transducer coupled to a backing element, the ultrasound transducer being generally disc shaped, and wherein the backing element is adapted to reflect ultrasound energy from the ultrasound transducer towards a distal end of the ablation catheter, the ultrasound energy being directed distally from a distally facing surface of the disc, and wherein fluid from the fluid source exits a lumen of the ablation catheter and flows past the transducer to provide for cooling thereof, and wherein the fluid provides a barrier between the transducer and blood so as to prevent blood from coagulating on the transducer.