Cardiac ablation devices

A method of performing cardiac ablation comprising:

• (a) providing an ablation device in a chamber of the heart of a mammalian subject such that the device is in an operative configuration with a distal side of the device facing toward a region of the cardiac structure to be ablated;
• and
• (b) while the ablation device is in said operative configuration, injecting a contrast medium into said chamber on the distal side of said ablation device.

Apparatus comprising:

• (a) a catheter having proximal and distal ends;
• (b) an expansible structure mounted to said catheter adjacent the distal end thereof, said expansible structure having proximal and distal ends, an expanded condition and a collapsed condition, said proximal and distal ends being closer to one another in said expanded condition than in said collapsed condition;
• (c) a reinforcing structure including a plurality of engagement elements disposed at least partially within said expansible structure, a first one of said engagement elements being connected to the distal end of the expansible structure, a second one of said engagement elements being connected to the distal end of said expansible structure, said engagement elements being engaged with one another when said expansible structure is in said expanded condition and disengaged from one another when said expansible structure is in said collapsed condition so that said reinforcing structure is more flexible when said expansible structure is in said collapsed condition than when said expansible structure is in said expanded condition, said engagement elements having interlocking features which prevent complete separation of said engagement elements from one another.

Ultrasonic ablation apparatus for ablating a region of the cardiac structure adjacent an ostium of a blood vessel extending to or from the heart comprising:

• (a) a catheter having proximal and distal ends;
• (b) an ultrasonic ablation device mounted to said catheter adjacent the distal end thereof, said ultrasonic ablation device said ablation device being adapted for positioning in a blood vessel and defining a forward-to-rearward axis extending generally coaxial with the blood vessel with the rearward direction being the direction toward the heart, said ultrasonic ablation device being adapted to direct ultrasonic waves from said emitter in a rearward direction toward the heart onto at least a portion of a ring-like region of the cardiac structure encircling said forward to rearward axis rearwardly of the device.

A method of cardiac ablation comprising the steps of:

• (a) positioning an ablation device within a blood vessel extending to or from the heart so that a forward-to-rearward axis of the ablation device is generally coaxial with the blood vessel;
• and
• (b) directing ultrasonic waves from said ablation device generally rearwardly and outwardly from the axis so that the ultrasonic waves are directed onto at least a portion of a ring-like region encircling the axis rearwardly of the device.

A method as claimed in claim 57 wherein said blood vessel is a pulmonary vein and said ring-like region is disposed in the ostium of the pulmonary vein or in the cardiac wall encircling the ostium.

Apparatus for ablating the cardiac wall surrounding one or more pulmonary veins comprising an ultrasonic emitter arranged to emit ultrasonic waves directed outwardly from a forward-to-rearward axis and an ultrasonic reflector at least partially surrounding said axis and adapted to focus ultrasonic waves onto at least a portion of a ring-like region having a diameter between 28 and 38 mm.

Apparatus for ablating the cardiac wall comprising an ultrasonic emitter arranged to emit ultrasonic waves directed outwardly from a forward-to-rearward axis and a reflector having a plurality of active regions at least partially surrounding said axis, each said active region being arranged to focus ultrasonic waves into at least a portion of a loop-like focal region associated with that active region, each said focal region at least partially surrounding said axis, different focal regions associated with different ones of said active regions having different diameters.

Apparatus for cardiac ablation comprising:

• (a) an expansible reflector surrounding a forward-to-rearward axis;
• and
• (b) an ultrasonic emitter adapted to direct ultrasonic waves generally outwardly from said axis and rearwardly so that the ultrasonic waves impinge on the reflector and is reflected generally forwardly and outwardly from said axis.

Ultrasonic apparatus comprising:

• (a) an ultrasonic emitter;
• and
• (b) an inflatable structure defining one or more reflective surfaces defining a channel having an entry and an exit window, said ultrasonic emitter being adapted to direct ultrasonic waves into the entry of said channel, said one or more reflective surfaces being adapted to direct the ultrasonic waves through said channel from said entry to said exit window.

Ultrasonic apparatus comprising:

• (a) a ultrasonic emitter having an emission surface in the form of at least a sector of a surface of revolution about an axis and adapted to direct ultrasonic waves generally radially outwardly away from said central axis;
• and
• (b) a Fresnel lens at least partially encircling said emitter, said lens being constructed and arranged to deflect radially-directed ultrasonic waves axially along said central axis.