the features and other details of the invention will now be more particularly described and pointed out in the claims . it will be understood that the particular embodiments of the invention are shown by way of illustration and not as limitations of the invention . the principle features of this invention can be employed in various embodiments without departing from the scope of the invention . in fig1 a balloon catheter 50 for cardiac ablation is shown including a primary balloon member 56 disposed about a catheter 14 for inflation ( via port 23 ) within the body ( e . g ., with the heart ) to provide a transmission waveguide for projecting radiation 13 to the ablation site 12 . the primary balloon member 56 is generally or substantially sealed and can be inflated to position the catheter 14 within a lumen . the catheter 14 is typically an elongated hollow instrument having at least one lumen 23 . the primary balloon 56 is shown engaged in direct contact with a body lumen 52 ( e . g . a pulmonary vein ). a sheath 16 is partially disposed about the primary balloon member 56 for providing irrigation ( via conduit 20 ) to the body lumen . primary balloon member 56 and sheath 16 form the inner and outer membranes of the present invention . in fig2 the balloon catheter of fig1 is shown in use . fluid 17 , introduced between the inner membrane formed by the primary balloon member 56 and the outer membrane formed by sheath 16 , provides irrigation to an inner body lumen region 26 . the fluid 17 can be any physiologically compatible fluid , such as saline . once the fluid 17 is introduced into the lumen region 26 , any blood or other substance remaining in the region is flushed out . another embodiment of balloon catheter 50 is shown in fig3 having two conduits 20 and 24 within the catheter 14 . conduit 20 provides irrigation fluid , such as saline , to the sheath 16 . conduit 24 provides inflation fluid , such as deuterium oxide ( d 2 o ), to the primary balloon member 56 . fig4 illustrates another embodiment of the balloon catheter of the present invention . the opening 22 of the sheath 16 is positioned to deliver fluid 17 to the target ablation site 12 . this approach allows the fluid to contact the ablation site , thereby cooling the tissue to prevent over - heating or coagulation . fig5 illustrates another embodiment of the balloon catheter of the present invention . the sheath 16 contains pores 19 for releasing fluid near or at the target ablation site 12 . one having ordinary skill in the art will readily appreciate that the pores can be any shape or size . in addition , the sheath 16 can be sealed on both ends . a person having ordinary skill in the art will readily appreciate that the size , quantity , and placement of the pores 19 , and the position of the sheath opening 22 can be used in conjunction with one another to provide a desired amount of fluid to the treatment site . in another embodiment , the primary balloon 56 is preshaped to form a parabolic like shape . this is accomplished by shaping and melting a teflon ® film in a preshaped mold to effect the desired form . the primary balloon 56 and sheath 16 of the present invention are preferably made of thin wall polyethylene teraphthalate ( pet ). the thickness of the membranes is preferably 5 - 50 micrometers , and more preferable , 10 - 20 micrometers . when inflated , the diameter of the membranes is preferably in the range of 20 - 30 millimeters . the balloon catheters of the present invention can be used for a variety of procedures , including laparoscopic , endoluminal , perivisceral , endoscopic , thoracoscopic , intra - articular and hybrid approaches . for example , atrial therapies can be performed by inserting an apparatus of the invention into the femoral vein . the catheter 14 having inner and outer membranes , e . g . primary balloon 56 and sheath 16 , fixedly attached thereto is guided through the inferior vena cava , and into the right atrium , and if required , it is guided into the left atrium via atrial septal puncture . left ventricular treatment can be performed by inserting flexible elongate member 32 into the femoral artery . the catheter 14 is guided through the iliac artery , the aorta , through the aortic valve and into adjacent to the left ventricle . once the primary balloon 56 is proximate to the tissue ablation site , a solution can be injected through lumen 20 into the sheath 16 to force blood and / or body fluids away from the treatment site . an optical apparatus is then guided through catheter 14 to a position proximate to the tissue ablation site 12 and energy , e . g ., laser energy , is emitted through primary balloon 56 . preferably , the composition of the primary balloon member 56 is transparent to the energy emitted through optical apparatus . the primary balloon and sheath can be deflated by applying a vacuum that removes the fluid from the balloon . a syringe or other known methods can be used to remove the fluid . once the primary balloon and sheath are fully deflated , the catheter can be easily removed from the body lumen . the term lumen , including derivatives thereof , is herein intended to mean any cavity or lumen within the body which is defined at least in part by a tissue wall . for example , cardiac chambers , the uterus , the regions of the gastrointestinal tract , the urinary tract , and the arterial or venous vessels are all considered illustrative examples of body spaces within the intended meaning . the term “ catheter ” as used herein is intended to encompass any hollow instrument capable of penetrating body tissue or interstitial cavities and providing a conduit for selectively injecting a solution or gas , including without limitation , venous and arterial conduits of various sizes and shapes , bronchioscopes , endoscopes , cystoscopes , culpascopes , colonscopes , trocars , laparoscopes and the like . catheters of the present invention can be constructed with biocompatible materials known to those skilled in the art such as those listed supra , e . g ., silastic , polyethylene , teflon , polyurethanes , etc . it should be understood that the term “ balloon ” encompasses deformable hollow shapes which can be inflated into various configurations including balloon , circular , tear drop , etc ., shapes dependent upon the requirements of the body cavity . the term “ transparent ” is well recognized in the art and is intended to include those materials which allow transmission of energy through , for example , the primary balloon member . preferred transparent materials do not significantly impede ( e . g ., result in losses of over 20 percent of energy transmitted ) the energy being transferred from an energy emitter to the tissue or cell site . suitable transparent materials include fluoropolymers , for example , fluorinated ethylene propylene ( fep ), perfluoroalkoxy resin ( pfa ), polytetrafluoroethylene ( ptfe ), and ethylene - tetrafluoroethylene ( etfe ). those having ordinary skill in the art will know , or be able to ascertain , using no more than routine experimentation , many equivalents to the specific embodiments of the invention described herein . these and all other equivalents are intended to be encompassed by the following claims . all publications and references cited herein including those in the background section are expressly incorporated herein by reference in their entirety .
the present invention is directed to a balloon catheter having an irrigation sheath . the balloon catheter has a first expandable membrane forming an occluding balloon . a second membrane forms a sheath about the occluding balloon for providing irrigation to a body lumen . fluid is provided to the occluding balloon to position the catheter and / or occlude the flow of blood . fluid is then passed through the sheath to irrigate the target site . in one embodiment of the present invention , the sheath has a plurality of fluid releasing pores .