1. A catheter comprising: an elongated catheter body； an end electrode located distally relative to the catheter body； moreover, the end electrode contains: a shell having a proximal portion of the neck and a distal chamber； a support element having a proximal and distal portions, while the proximal portion is inserted into the portion of the neck of the sheath, and the distal portion extends into the sheath chamber, the proximal portion having a through hole for fluid environment； and a fluid channel provided between the portion of the neck of the sheath and the proximal portion of the support member to form a passage for the fluid between the through hole and the chamber. 2. The catheter according to claim 1, further comprising a position sensor that is at least partially enclosed in a distal portion of the support member. The catheter according to claim 1, wherein the fluid channel is formed on the outer surface of the distal portion of the support member. The catheter of claim 3, wherein the fluid channel has a spiral pattern on the outer surface. The catheter according to claim 3, wherein the fluid channel has radial and axial branches. The catheter according to claim 4, wherein the spiral pattern extends at least about 360 degrees along the length of the distal portion of the support member. The catheter according to claim 4, wherein the spiral pattern extends at least about 720 degrees along the length of the distal portion of the support member. The catheter of claim 4, wherein the spiral pattern extends at least about 1080 degrees along the length of the distal portion of the support member. The catheter according to claim 1, in which the proximal portion of the support element in1. Катетер, содержащий:удлиненный корпус катетера；концевой электрод, расположенный дистально относительно корпуса катетера； причем концевой электрод содержит:оболочку, имеющую проксимальный участок шейки и дистальную камеру；опорный элемент, имеющий проксимальный и дистальный участк
