Shock wave electrodes
Disclosed herein shock wave catheters comprising one or more shock wave electrodes for cracking calcifications located within blood vessels. In some variations, a shock wave catheter has first and second shock wave electrodes each circumferentially disposed over the outer surface of the catheter. In certain variations, the first electrode has a recess and the second electrode has a protrusion that is received by the recess and a spark gap is located along the separation between the recess and the protrusion. The second electrode can also have a recess that receives a protrusion from a third shock wave electrode, where the separation between the second and third electrodes along the separation between the recess and the protrusion forms a second spark gap. A shock wave can be initiated across these spark gaps when a voltage is applied over the electrodes.
1. A treatment catheter comprising:
an axially extending elongate member;
a cylindrical conductive band mounted on the elongate member, the cylindrical conductive band having a spiral groove beginning near one end of the cylindrical conductive band and terminating intermediate the length of the cylindrical conductive band;
a first wire having a first end electrically connectable to a voltage source and having a second end received in the spiral groove, the tip of the second end of the wire being spaced from the terminated end of the groove to define a spark gap;
a second wire having a first end electrically connectable to a voltage source and a second end electrically connected to the cylindrical conductive band; and
a tube connected to the elongate member and surrounding the cylindrical conductive band, the tube being fillable with a conductive liquid, wherein when a voltage pulse is applied across the first and second wires a current will flow across the spark gap and generate a shock wave in the liquid.
2. The catheter of claim 1 wherein the cylindrical conductive band includes a second spiral groove beginning near the other end of the cylindrical conductive band and terminating intermediate the length of the cylindrical conductive band and wherein the second end of the second wire is disposed in the second groove to provide the electrical connection between the second wire and the cylindrical conductive band.
3. The catheter of claim 2 wherein the first groove has a width larger than the width of the second groove and the second end of the first wire is loosely disposed in the first groove.
4. The catheter of claim 1 wherein the tube is an inflatable angioplasty balloon.
5. The catheter of claim 1 wherein the elongate member includes a guide wire lumen.