Methods and apparatus employing ionizing radiation for treatment of cardiac arrhythmia

A method for modifying the conduction characteristics of the AV node of a human heart comprising exposing the cardiac tissue comprising the AV node to ionizing radiation from an ionizing radiation source in immediate proximity to or contact with such tissue without completely ablating the AV node.

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 therealong and remotely actuated control means for changing the shape of the distal end portion or a part thereof.

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.

Apparatus for insertion into a chamber of the 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 heart, the fixation device including an ionizing radiation source for treating cardiac tissue in proximity to or contact with the source.

A method for treating atrial fibrillation comprising:

• defining a plurality of lines of ablated tissue in the wall of the left atrium by exposing selected cardiac tissue to ionizing radiation from an ionizing radiation source in proximity to or contact with the selected tissue.

A method for treating pulmonary vein stenosis comprising exposing the interior surface of the pulmonary vein to ionizing radiation from an ionizing radiation source in proximity to or contact with such surface.

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.

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 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.