Methods and apparatus employing ionizing radiation for treatment of cardiac arrhythmia

Abstract

Method and apparatus are disclosed employing ionizing radiation. for forming lines of ablation or lesions in cardiac tissue to treat atrial fibrillation or other electrophysiological problems with the heart. The apparatus may include a catheter in which the radiation source is advanced hydraulically after the catheter is in place within the heart. Various fixation devices are also disclosed for fixing the location of the catheter within the heart.

1 . Apparatus for treating cardiac tissue comprising an elongated catheter including proximal and distal end portions and defining a passageway extending between the end portions for receiving an ionizing radiation source there along; and remotely actuated control means for changing the shape of the distal end portion or a part thereof. 
     
     
         2 . The Apparatus of  claim 1  in which the remotely actuated control means comprises a fixation device carried at the distal portion of the catheter and adapted to hold the catheter against an endocardial surface. 
     
     
         3 . The apparatus of  claim 1  in which a fixation device is movable between a retracted position for insertion of the catheter and expanded position to hold the catheter in a desired location. 
     
     
         4 . The apparatus of  claim 1  in which a fixation device includes a plurality of ribs that extend generally parallel to the catheter in the retracted position during insertion and are movable to an expanded position to hold the catheter in a desired location. 
     
     
         5 . The apparatus of  claim 4  in which the ribs are disposed to move away from catheter to an expanded position when the distal end portion of the catheter is curved, the catheter including a remotely controllable pull wire for causing the distal end portion of the catheter to curve. 
     
     
         6 . The apparatus of  claim 4  in which the ribs are biased to anormally expanded position and the catheter includes an axially movable sleeve disposed on the distal portion of the catheter and movable between a first position overlying the ribs and holding them adjacent to the catheter and a second position where the ribs are allowed to expand. 
     
     
         7 . The apparatus of  claim 4  in which the ribs comprise a shape memory material and are disposed to assume the expanded condition when exposed to body temperature. 
     
     
         8 . The apparatus of  claim 1  further comprising at least one electrode at the distal end portion of the catheter to sense an electrophysiological characteristic of cardiac tissue. 
     
     
         9 . The apparatus of  claim 8  comprising at least two spaced apart electrodes. 
     
     
         10 . The apparatus of  claim 3  wherein a fixation device comprises an inflatable member. 
     
     
         11 . The apparatus of  claim 3  wherein the catheter includes an inflation lumen extending between the proximal and distal end portions and a fixation device includes a balloon carried at the distal end portion and communicating with me inflation lumen. 
     
     
         12 . The apparatus of  claim 11  wherein the balloon extends less than 360° around the catheter shaft. 
     
     
         13 . The apparatus of  claim 1  further comprising an ionizing radiation source located in the passageway. 
     
     
         14 . The apparatus of  claim 1  further comprising a guide wire passageway extending through at least the catheter distal end portion or a part thereof. 
     
     
         15 . The apparatus of  claim 2  wherein the fixation device comprises one or more suction ports for suction attachment to a cardiac surface. 
     
     
         16 . The apparatus of  claim 2  wherein the fixation device comprises one or more anchors to engage a cardiac surface and hold the distal end portion. 
     
     
         17 . Apparatus for treating cardiac tissue comprising a flexible elongated catheter having a proximal end portion and a distal end portion and defining a passageway extending between the proximal and distal end portions for passage of an ionizing radiation source therealong, the distal end portion of the catheter defining pre-shaped section disposed to engage the cardiac tissue at a desired location. 
     
     
         18 . The apparatus of  claim 17  in which the pre-shaped section is spiral shaped to contact the inner surface of a pulmonary vein. 
     
     
         19 . The apparatus of  claim 17  in which the distal end portion of the catheter is sufficiently flexible to conform to the shape of a guide wire and a method includes advancing the distal end portion of the catheter along a guide wire to the cardiac tissue to be treated. 
     
     
         20 . The apparatus of  claim 19  in which the pre-shaped section of the catheter assumes the pre-shape upon withdrawal of the guide wire from the distal end portion. 
     
     
         21 . Apparatus for insertion into a chamber of a human heart for treating cardiac tissue, the apparatus comprising a flexible elongated member having a proximal end portion and a distal end portion, a fixation device being movable between a retracted position for insertion of the member and an expanded position to hold the distal end portion in a desired location within the human heart, the fixation device including an ionizing radiation source for treating cardiac tissue in proximity to or contact with the source. 
     
     
         22 . The Apparatus of  claim 21  in which the fixation device includes a plurality of ribs that extend generally parallel to the elongated member in the retracted position and are movable to an expanded position to hold the member in the desired location, the ionizing radiation source being located on one or more of the ribs. 
     
     
         23 . The apparatus of  claim 21  in which the ionizing radiation source is a beta emitter. 
     
     
         24 . A flexible elongated catheter comprising a distal end portion and a proximal end portion, first and second lumen extending between the proximal and distal end portions, the first lumen receiving a steering wire extending between the proximal and distal end portions and fixed to the catheter in the distal end portion, the second lumen receiving a steering wire extending between the proximal and distal end portions and fixed to the catheter at the distal end portion, at least one of the steering wires including a curve-accommodating segment for accommodating curving of the catheter in proximity to the segment when push or pull forces are applied to the proximal ends of the steering wires. 
     
     
         25 . The flexible elongated catheter of  claim 24  wherein the steering wires comprised a single elongated wire that extends from the proximal end through the first lumen to the distal end portion and through the second lumen to the proximal end portion, the wire being continuous in the distal end portion of the catheter. 
     
     
         26 . The flexible elongated catheter of  claim 24  wherein the steering wires comprise separate wires. 
     
     
         27 . The flexible elongated catheter of  claim 24  wherein one of the wires comprises a bend in the distal end portion and the receiving said first or said second lumen includes an obstruction for engaging the bend when the wire is pulled to cause the wire and the distal end portion of the catheter to assume a curved shape. 
     
     
         28 . The flexible elongated catheter of  claim 25  wherein the catheter includes a third and a fourth lumen extending between the proximal and distal end portions. 
     
     
         29 . The flexible elongated catheter of  claim 27  wherein the bend and the curve-accommodating segment are located in the same lumen. 
     
     
         30 . The flexible elongated catheter of  claim 27  wherein the bend is proximal to the obstruction. 
     
     
         31 . The flexible elongated catheter of  claim 29  further comprises a U-shaped lumen connector in the distal end portion connecting the third and fourth lumen in a fluid-communicating relationship. 
     
     
         32 . The flexible elongated catheter of  claim 31  wherein the curve-accommodating segment comprises a plurality of undulations formed in the wire. 
     
     
         33 . The flexible elongated catheter of  claim 32  wherein the curve-accommodating segment comprises a plurality of coils formed in the wire. 
     
     
         34 . The flexible elongated catheter of  claim 27  in which the bend comprises a generally U-shaped or V-shaped segment in the wire. 
     
     
         35 . A flexible elongated catheter comprising a distal end portion and a proximal end portion, first and second lumen extending between the proximal and distal end portions, the first lumen receiving a steering wire extending between the proximal and distal end portions and fixed to the catheter in the distal end portion, the second lumen receiving a steering wire extending between the proximal and distal end portions and fixed to the catheter at the distal end portion, at least one of the steering wires including a bend in the distal end portion, and the receiving said first or said second lumen includes an obstruction for engaging the bend when the wire is pulled to cause the distal end portion of the catheter to assume a curved shape. 
     
     
         36 . The catheter of  claim 35  in which the steering wires comprised a single elongated wire that extends from the proximal end through the first lumen to the distal end portion and through the second lumen to the proximal end portion, the wire being continuous in the distal end portion of the catheter. 
     
     
         37 . The catheter of  claim 35  in which the steering wires comprise separate wires. 
     
     
         38 . The catheter of  claim 35  wherein the catheter includes third and fourth lumen extending between the proximal and distal end portions. 
     
     
         39 . The catheter of  claim 35  wherein the bend comprises a generally U-shaped or V-shaped segment in the wire. 
     
     
         40 . The catheter of  claim 38  wherein the catheter comprises a U-shaped lumen connector in the distal end portion connecting the third and fourth lumen in a communicating relationship.