Abstract:
A system for providing ablation comprising a fluid source that contains a volume of biocompatible ablation fluid. The system also comprises a heater that heats the ablation fluid and provides heated ablation fluid. The system further comprises an ablation applicator, spaced apart from the heater, and having a perimeter edge configured to engage tissue surround an area of tissue, the ablation applicator applying ablation fluid to the area of tissue. The system still further comprises a suction source for removing the ablation fluid from the area of tissue.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a system and method of ablation in surgical procedures. 
       BACKGROUND 
       [0002]    Atrial fibrillation results from disorganized electrical activity in the heart muscle, or myocardium. A surgical maze procedure has been developed for treating atrial fibrillation and the procedure involves the creation of a series of surgical incisions through the atrial myocardium in a preselected pattern so as to create conductive corridors of viable tissue bounded by scar tissue. 
         [0003]    As an alternative to the surgical incisions used in the maze procedure, transmural ablation of the heart wall has been proposed. Such ablation may be performed either from within the chambers of the heart (endocardial ablation) using endovascular devices (e.g., catheters) introduced through arteries or veins, or from outside the heart (epicardial ablation) using devices introduced into the chest. Various ablation technologies have been proposed, including cryogenic, radiofrequency (RF), laser and microwave. The ablation devices are used to create transmural lesions, that is, lesions extending through a sufficient thickness of the myocardium to block electrical conduction, which form the boundaries of the conductive corridors in the atrial myocardium. Perhaps most advantageous about the use of transmural ablation rather than surgical incisions is the ability to perform the procedure on the beating heart without the use of cardiopulmonary bypass. 
       SUMMARY 
       [0004]    One aspect of the present invention relates to a system for providing ablation comprising a fluid source that contains a volume of biocompatible ablation fluid. The system also comprises a heater that heats the ablation fluid and provides heated ablation fluid. The system further comprises an ablation applicator, spaced apart from the heater, and having a perimeter edge configured to engage tissue and surround an area of tissue, the ablation applicator applies ablation fluid to the area of tissue. The system still further comprises a suction source for removing the ablation fluid from the area of tissue. 
         [0005]    Another aspect of the present invention relates to a method for performing ablation comprising heating, by a heat source, ablation fluid to a predetermined temperature. The method also comprises providing the heated ablation fluid to an ablation applicator that is spaced apart from the heat source by a conduit. The method further comprises ablating a tissue area of a patient located within a volume define by the tissue and the ablation applicator. The method still further comprises removing, by a suction source, heated ablation fluid from the volume. 
         [0006]    Still another aspect of the present invention relates to a system for providing ablation comprising means for holding/containing a volume of an ablation fluid. The system also comprises means for heating a portion of the ablation fluid. The system further comprises means for applying the heated ablation fluid that is spaced apart from the means for heating to a surface area define by an area of tissue surrounded by the means for applying. The system still further comprises means for applying negative pressure to remove the heated ablation fluid from the surface area. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  illustrates an example of an ablation system in accordance with an aspect of the invention. 
           [0008]      FIG. 2  illustrates an example of an ablation applicator in accordance with an aspect of the invention. 
           [0009]      FIG. 3  illustrates another example of an ablation applicator in accordance with an aspect of the invention. 
           [0010]      FIG. 4  illustrates another example of an ablation applicator in accordance with an aspect of the invention. 
           [0011]      FIG. 5  illustrates an example of an ablation procedure performed on a heart in accordance with an aspect of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The present invention relates to a system and method for ablating tissue. The heating of the tissue kills the tissue, while leaving the surrounding tissue unharmed. 
         [0013]      FIG. 1  illustrates an example of an ablation system  100  in accordance with an aspect of the invention. The ablation system  100  includes an ablation fluid source  102  that provides ablation fluid for use in ablation tissue. The fluid from the source  102  is provided to a heater  104 . The ablation fluid can be, for example, a substantially sterile saline solution or other biocompatible fluid. The ablation fluid source  102  can be implemented as a passive container that holds the fluid, such as for example, as a drip bag, which can employ gravity to supply the fluid or fluid can be retrieved by a pump or other device. Alternatively, the source  102  can include a pump that supplies the fluid to the heater  104 . Thusly, the ablation fluid source  102  can provide means for holding/containing a volume of the ablation fluid. The ablation fluid source  102  can include, for example, an adjustable valve  106 , such as a ball valve, gate valve or globe valve. The valve  106  can include, for example, an OFF setting that prevents the flow of ablation fluid, and an ON setting that allows the flow of ablation fluid. The valve  106  can, for example, the rate of flow of ablation fluid provided by the ablation fluid source  102  by a setting between the ON and OFF settings. Alternative flow can be controlled by electrical or mechanical control of an associated pump. 
         [0014]    The ablation fluid source  102  can be connected to the heater  104 , for example, by one or more lengths of a flexible tube  108  or other conduit. The flexible tube  108  could be implemented, for example, as a insulated or non-insulated silicone tube. The flexible tube  108  could be implemented as a separate component from the ablation fluid source  102 , having first and second ends. In such an example, the first end of the flexible tube  108  could be removeably connected to an outlet or part of the source  102  such as or to the adjustable valve  106  of the ablation fluid source  102 . The second end of the flexible tube  108  can be removeably connected to the input port  110  the heater  104 . Alternatively, the flexible tube  108  could be integrally formed on the ablation fluid source  102 , wherein an end of the flexible tube  108  is connected to an input port  110  of the heater  104 . It is to be understood that integral formation includes monolithic formation processes, such as injection molding. The ablation fluid can flow within a lumen of the flexible tube  108  from the ablation fluid source  102  to the input port  110  of the heater  104 . 
         [0015]    The heater  104  can receive the ablation fluid at the input port  110 , heat the ablation fluid and provide heated ablation fluid at an output port  112 . The heated ablation fluid can be supplied to an ablation applicator  114  for use in ablating selected tissue. The ablation applicator  114  can be connected to the heater by a connector tube  116 . The heater  104  can include one or more heating elements  118  that can be controlled, for example, by a temperature controller  120 . 
         [0016]    As one example, the heater  104  can include a chamber for heating the liquid from the fluid source  102 . As one example, the chamber can store heating liquid, such as water, or other fluid with a relatively high specific heat (e.g., a specific heat of at least about 4 Joules per gram per degree Celsius). The heater  104  can also include an immersion tube, for example, which can be implemented as elongated tube that is immersed in the heating liquid. The immersion tube can connect the input port  110  to the output port  112  of the heater  104 , such that ablation fluid can flow within a lumen of the immersion tube from the input port  110  to the output port  112  of the heater  104 . The immersion tube can, for example, be formed out of a conductive material, such as copper or aluminum, which is heated by the one or more heating elements  118 . The immersion tube can, for example, be shaped as a coil such that the ablation fluid flowing through in the immersion tube can be heated by the heating fluid. Thusly, the heating fluid and the immersion tube can act as a medium of heat transfer between the heating element  118  and the ablation fluid flowing in the lumen of the immersion tube. Upon exiting the heater  104  through the output port  112 , the ablation fluid can have approximately the same temperature as the heating fluid. The heater  104  thus can provide means for heating a portion of the ablation fluid. 
         [0017]    As stated above, the heater  104  and the ablation applicator  114  can be connected by the connector tube  116 . The connector tube  116  can be implemented, for example, as an elongated flexible tube or other insulated conduit. The connector tube  116  can include, for example, a first end a spaced apart from a second end. In such an example, the first end of the connector tube  116  could be removeably connected to the output port  112  of the heater  104  and the second end of the connector tube  116  could be removeably connected to an input port  117  of the ablation applicator  114 . Alternatively, the connector tube  116  could be integrally formed with the ablation applicator  114 . The connector tube  116  can be formed, for example, out of a compliant material, such as rubber, silicone or plastic to name a few. It is to be understood that, as used herein, the term rubber includes any of a variety of synthetic and/or natural elastic materials whose properties resemble natural rubber. It is to be further understood that the term plastic includes any of a variety of polymers that are compliant at room temperature The connector tube  116  can cause fluid communication between the heater  104  and the ablation applicator  114 , such that heated ablation fluid can flow in a lumen of the connector tube  116  from the heater  104  to the ablation applicator  114 . 
         [0018]    The ablation applicator  114  receives the heated ablation fluid and can directly apply the heated ablation fluid to living tissue. The area of tissue which comes into direct contact with the heated ablation fluid is referred to herein as an ablation site. The ablation site can be located either by a process called mapping, in which the ablation applicator is moved from spot to spot until the appropriate area is found. Alternatively, the applicator  114  can be positioned at the ablation site under direct vision (in the case of an open chest procedure). As one example, the applicator can be robotically positioned at a desired implantation site as part of a partially or fully automated procedure. The ablation applicator  114  can be formed, for example, out of a non-conductive material, such as rubber or silicone or plastic or a combination of materials. An interior of the ablation applicator  114  can hold a volume of the heated ablation fluid. For instance, an open end of the applicator  114  can have a perimeter dimensioned and configured to contact the heart so that the ablation site resides in an area defined by the open end of the applicator. Heated ablation fluid flows into the volume defined by the ablation site and the interior surface of the application  114 . When the living tissue comes into direct contact with the heated ablation fluid, the tissue will heat. For instance, the ablation fluid can be heated to approximately 65 degrees Celsius, such that the cells contacted by the heated ablation fluid will be destroyed (or killed) upon contact. A layer of tissue below the surfaces can also be destroyed according to the temperature of the ablation fluid and the duration such fluid is applied to the tissue. 
         [0019]    The system  100  can also include a temperature control system  120  that provides means for controlling the temperature of the heated ablation fluid at the ablation site. The temperature control system can include, for example, a temperature sensor  122 . The temperature sensor  122  can be implemented, for example, as a thermistor, an electronic thermometer or other temperature sensor. The temperature sensor  122  can sense the temperature of the heated ablation fluid within the ablation applicator  114 , or alternatively, the temperature sensor  122  can sense the temperature of tissue. The temperature sensor  122  can be implemented as part of the ablation applicator  114 . Alternatively, the temperature sensor  122  can sense the temperature of tissue. As one example, the temperature sensor  122  can be integrally formed into a housing of the ablation applicator  114 . The temperature sensor  122  can provide a signal to the temperature controller  120  that characterizes the temperature sensed by the temperature sensor  122 . The temperature controller  120  can be implemented, for example, as a microcontroller, a thermocouple, or other software and/or hardware. 
         [0020]    The temperature controller  120  can be programmable, such that a user of the ablation system  100  can set a desired temperature for the heated ablation fluid. The temperature controller  120  receives the signal from the temperature sensor  122  and adjusts the intensity of the heating element  118  of the heater  104  based on the received signal and the desired temperature. Accordingly, the temperature controller  120  can control the temperature of the heated ablation fluid leaving the heater  104 . The temperature controller  120  can ensure that the temperature of the heated ablation fluid stays at or near the desired temperature when the ablation fluid is at the ablation site. In this way, the temperature control system can provide closed loop temperature control. The temperature can be fixed or it can be programmable. 
         [0021]    A suction source  124  can be implemented to cause the flow of ablation fluid from the source to the ablation application  114 . The suction source  124  and the ablation applicator  114  can be connected by a suction tube  126 . The suction tube  126  can be implemented, for example, as an elongated flexible tube or other conduit. The suction tube  126  could be formed, for example, out of rubber, silicone or plastic. The suction tube  126  could be formed separate from the suction source  124  and the ablation applicator  114 . In such an example, the suction tube  126  can include a first and second end, wherein the first end is removeably connected to the suction source  124  and the second end is removeably connected to an output port  128  of the ablation applicator  114 . Alternatively, the suction tube  126  could be integrally formed on the ablation applicator  114 , and an end of the suction tube  126  could be removeably connected to the suction source  124 . In another alternative, the suction tube  126  could be integrally formed with the suction source  124 , and an end of the suction tube  126  could be removeably connected to the output port  128  of the ablation applicator  114 . 
         [0022]    The suction source  124 , via the suction tube  126  can apply a negative pressure of about −14 to about −103 kilopascals (approximately −2 to −15 pounds per square inch) at the output port  128  of the ablation applicator  114 . Application of the negative pressure can create a partial vacuum to pull the heated ablation fluid from the ablation fluid source  102 , through the heater  104 , to within the ablation applicator  114 , and from the ablation applicator  114  to a waste reservoir (not shown). It is to be understood that the waste reservoir could be implemented as a container within the suction source  124 , or as separate container spaced apart from the suction source  124 . Appropriate controls can be provided to selectively activate and deactivate the solution source  124  to apply heated ablation fluid to the desired site(s). The suction source  124  can thus provide means for applying negative pressure to cause flow of the ablation fluid into the applicator  114  and to remove the heated ablation fluid from the ablation site. 
         [0023]    By way of further example, the ablation applicator  114  can be placed at a specific ablation site during surgery. The ablation applicator  114  can be placed at the ablation site, for example, robotically or endoscopically. Typically, while the ablation applicator  114  is being positioned at the ablation site the valve  106  of the ablation fluid source  102  can be set to an OFF setting or other controls can configure the system  100 , such that no ablation fluid is flowing through the ablation system  100 . When the ablation applicator  114  is positioned at a desired ablation site, the suction source  124  can be activated to establish a substantially airtight seal around an edge of the ablation applicator  114  and the area of tissue engaged with the ablation applicator  114 . 
         [0024]    When the substantially airtight seal is established, the adjustable valve  106  on the ablation fluid source  102  or other controls can be set to an ON setting, such that ablation fluid can flow through the ablation system  100 . The negative pressure applied by the suction source  124  causes ablation fluid to flow from the ablation fluid source  102  to the heater  104  via the lumen of the flexible tube  108 . The ablation fluid can then flow from the heater&#39;s  104  input port  110  to the heater&#39;s  104  output port  112 , thereby heating the fluid to a desired temperature. The heated ablation fluid can flow from the output port  112  of the heater  104  to the input port  117  of the ablation applicator  114  via the lumen of the connector tube  116 . 
         [0025]    When the ablation applicator  114  receives heated ablation fluid at the input port  117  and the suction source  124  provides the negative pressure at the output port  128  of the ablation applicator, the ablation applicator  114  maintains the relatively airtight seal around the area of tissue covered by the ablation applicator  114 . Such a seal can ensure that only a desired area (the ablation site) of tissue comes into contact with the heated ablation fluid, such that tissue that is not intended to be ablated is not harmed. Suction can be set to maintain a substantially constant volume of fluid within the applicator during ablation. For instance, the heated ablation fluid can substantially fill the volume defined by the interior of the ablation applicator  114  and the surface at the ablation site. In this way, the ablation applicator  114  can provide means for applying heated ablation fluid to the ablation site. The suction source  124  can remove the heated ablation fluid from the ablation applicator  114  via the lumen of the suction tube  126 , thereby creating a relatively constant flow of heated ablation fluid in the ablation applicator  114 . 
         [0026]    The ablation system  100  of the present invention allows a surgeon to accurately control the temperature of an ablation fluid (e.g., a saline solution), which can be directly applied to a desired ablation site. The heated ablation fluid can be directly applied by the ablation applicator  114 . For example, the ablation fluid is heated to a range of approximately 60-70 degrees Celsius, which is sufficient to kill cells in the tissue that the heated ablation fluid comes into direct contact with for a sufficient amount of time. Typically, this process can continue until the surgeon has ablated a desired amount of tissue. 
         [0027]    It is to be appreciated that the ablation applicator  114  could be formed in a variety or different size and shapes, as will be described herein. The size and shapes could depend, for example, on the size and shape of the tissue of anatomical structures that are to be ablated. In  FIG. 1 , the ablation applicator  114  illustrated includes a substantially circular shaped open contact edge, such as will be described in with respect to  FIG. 2 . 
         [0028]      FIG. 2  illustrates an example of an ablation applicator  200  that can be used in the ablation system  100 . The ablation applicator  200  can have substantially a hollow hemispherical housing wall  202  that forms a dome about an axis  203 . The ablation applicator  200  can be formed of a non-conductive and flexible material, such as silicone, plastic or rubber or a combination of materials. The ablation applicator  200 , could be formed, for example, by a monolithic injection molding process. The housing wall  202  of the ablation applicator  200  can be relatively thin (e.g., about 0.5-1.0 mm). The housing wall  202  of the ablation applicator  200  can be translucent, such that an observer of an ablation procedure can view an interior portion of the housing wall  202 . This can allow proper placement of the application as well as provide a view of the flow of fluid. 
         [0029]    An input port  204  and an output  206  can, for example, receive and provide heated ablation fluid, respectively, by allowing flow of the heated ablation fluid through a lumen of a respective input port  204  or output port  206 . It is to be understood that the input port  204  and the output port  206  can be interchangeable. The input port  204  and the output port  206  can be formed of a relatively rigid material, such as thermoplastic polyethylene terephthalate (PET) or silicon. Alternatively, the input port  204  and the output port  206  can be formed of the same or similar material as the ablation applicator  200 . The input port  204  and the output port  206  can include, for example, a first end  208  and a second end  210 . The first end  208  of the input port  204  and the output port  206  can be internal to the ablation applicator  200 . The second end  210  of the input port  204  and the output port  206  can, for example, be external to the ablation applicator  200 . The input port  204  could, for example, be implemented as a first tube that extends from a proximal end of the housing wall  202  and axially along or parallel to the axis  203 . The output port  206  can be implemented, for example, as a second tube that extends outwardly from the housing wall  202  and normal to the axis  203 , and is spaced apart from the first tube. 
         [0030]    The input port  204  and the output port  206  can be integrally formed with the ablation applicator  200 . Alternatively, the input port  204  and the output port  206  can be attached to ablation applicator  200  by press fitting the input port  204  and the output port  206  through an aperture of the ablation applicator  200  up to a shoulder piece  211  of the input port  204  and the output port  206 . The input port  204  and output port  206  can include, for example, a plurality of circumferentially extending ribs  216  or projections to provide increased friction fitting with attached tubes. Alternatively, the input port  204  and the output can be smooth. 
         [0031]    The dome shaped portion of the housing wall  202  can, for example, define a volume. The volume can, for example, hold heated ablation fluid that is flowing from the input port  204  to the output port  206 . A distal end of the ablation applicator  200  can, for example, form an open contact edge  212 . The contact edge  212 , can be for example, the portion of the ablation applicator  200  that engages tissue that surrounds an ablation site. The contact edge can lie substantially in a plane or have other contoured configurations. The contact edge  212  could be formed, for example, as a substantially circumferential opening. The contact edge  212  can include a ring portion  214  that can extend radially inwardly or outwardly from the axis  203 . The ring portion  214  can, for example, increase the efficiency of the airtight seal mentioned above, by increasing the surface area of the contact edge  212 . 
         [0032]      FIG. 3  illustrates another example of a kidney-shaped ablation applicator  300  in accordance with an aspect of the invention. The ablation applicator  300  can, for example, be formed by a monolithic injection molding process. Additionally, the ablation applicator  300  can be formed out of a non-conductive and flexible material, such as silicone, plastic or rubber. The ablation applicator  300  can include a first end  302  and a second end  304  residing on a plane  305 . The ablation applicator  300  can also include a middle portion  306  extending between the first end  302  and the second end  304 . The middle portion  306  can include an inner surface  308  and an outer surface  310  that are spaced apart. The inner surface  308  and the outer surface  310  can, for example, extend from the first end  302  to the second end  304 . The middle portion  306  can also include an arched portion  312  extending between the inner and outer surfaces  308  and  310 . The arched portion  312  can, for example, have a substantially semicircular cross section. The arched portion  312  can be relatively thin (e.g., about 0.5 mm to about 1.0 mm). The arched portion  312  defines a housing wall of the ablation applicator  300 . Additionally, the arched portion  312  can be substantially transparent, such as to allow an observer of an ablation procedure to view the interior of the arched portion  312 . The ablation applicator  300  can be applied to ablation sites with an asymmetric surface, such as a surface of a heart. 
         [0033]    The inner portion  308  and the outer portion  310  of the ablation applicator  300  can, for example, define a kidney-shaped contact edge  313 . That is, a portion of the contact edge  313  between the spaced apart ends  302  and  304  can be recessed concavely, as indicated at  315 . The contact edge  313  can be, for example, the portion of the ablation applicator  300  that engages tissue during an ablation procedure. The contact edge  313  can include, for example, a periphery portion extending inwardly or outwardly along the contact edge  313 . The periphery portion can increase the efficiency of the airtight seal mentioned above, by increasing the surface area of the portion of the ablation applicator  300  that engages a patient&#39;s tissue. The periphery portion can also be more pliant then a proximal portion of the application  300  to facilitate its engagement at an ablation site. 
         [0034]    The arched portion  312  of the ablation applicator  300  can define a volume for holding heated ablation fluid that flows from an input port  314  to an output port  316 . The volume can, for example, define the ablation site. The ablation site can thusly include an area of tissue located within the contact edge  313  and the housing wall  312  of the ablation applicator  300 . 
         [0035]    The input port  314  and the output port  316  can, for example, receive and provide heated ablation fluid, respectively, by allowing flow of the heated ablation fluid through a lumen of a respective input port  314  or output port  316 , similar to as described above with respect to  FIG. 2 . It is to be understood that the input port  314  and the output port  316  can be interchangeable. The input port  314  and the output port  316  can more rigid than the arched housing wall  312 . The input port  314  and the output port  316  can be formed of the same or similar material as the ablation applicator  300 . The input port  314  and the output port  316  can include, for example, a first end  318  and a second end  320 . The first end  318  of the input port  314  and the output port  316 , can for example, be internal to the ablation applicator  300 . The second end  320  of the input port  314  and the output port  316  can, for example, be extend outwardly from the housing wall  312  of the ablation applicator  300  and can extend normally to the plane  305 . The input port  314  and the output port  316  can be formed with the ablation applicator  300  similar to as mentioned with request to  FIG. 2 . The input port  314  and output port  316  can include, for example, a plurality of circumferentially extending ribs  324  or projections to provide increased friction fitting with attached tubes. 
         [0036]      FIG. 4  illustrates another example of a substantially C-shaped ablation applicator  400  in accordance with an aspect of the invention. The ablation applicator  400  can, for example, be formed by a monolithic injection molding process. Additionally, the ablation applicator  400  can be formed out of a non-conductive and flexible material, such as silicone, plastic or rubber. The ablation applicator  400  can include, for example, a first end  402  and a second end  404  residing on a plane  406 . The ablation applicator  400  can also include a middle body portion  408  extending arcuately between the first end  402  and the second end  404 . The middle portion  408  can include, for example, follow a substantially hollow C-shape having an inner C-shaped surface  410  and outer C-shaped surface  412 , wherein the inner surface  410  and outer surface  412  are spaced apart. The inner surface  410  and outer surface  412  can, for example, extend in a substantially fixed spaced apart relationship from the first end  402  to the second end  404 . The middle portion  408  can also include an arched housing wall portion  414  extending arcuately between the inner and outer surfaces  410  and  412 . The arched portion  414  can, for example, have a semicircular cross section. The arched portion  414  can be relatively thin (e.g., having a thickness of about 0.5 to about 1.0 millimeters). Additionally, the arched portion  414  can be translucent, such as to allow an observer of an ablation procedure to view the interior of the arched portion  414 . 
         [0037]    The inner surface  410  and the outer surface  412  of the ablation applicator  400  can define a contact edge  416  that engages tissue during an ablation procedure. The contact edge  416  can, for example, define a substantially hollow U- or C-shape such as shown in  FIG. 4 . The contact edge  416  can include, for example, a periphery portion extending inwardly or outwardly along the contact edge  416 . The periphery portion can increase the efficiency of the airtight seal mentioned above, by increasing the surface area of the portion of the ablation applicator  400  that comes into contact with a patient&#39;s tissue. 
         [0038]    The arched side wall portion  414  of the ablation applicator  400  can engage the ablation site to define a volume for holding heated ablation fluid that flows from an input port  418  to an output port  420 . 
         [0039]    The input port  418  and the output port  420  can, for example, receive and provide heated ablation fluid, respectively, by allowing flow of the heated ablation fluid through a lumen of a respective input port  418  or output port  420 . It is to be understood that the input port  418  and the output port  420  can be interchangeable (i.e., fluid can flow in either direction). The input port  418  and the output port  420  can include, for example, a first end  422  and a second end  424 . The first end  422  of the input port  418  and the output port  420 , can for example, be internal to the ablation applicator  400 . The second end  424  of the input port  418  and the output port  420  can extend outwardly from the respective ends  402  and  404  the ablation applicator  400 . The input port  418  and output port  420  can extend outwardly from the first and second ends  402  and  404 , respectively, of the ablation applicator  400  (e.g., extending normal to the plane  406 ). The input port  418  and output port  420  can include, for example, a plurality of circumferentially extending ribs  428  or projections to provide increased friction fitting with attached tubes. 
         [0040]      FIG. 5  illustrates an example of an ablation procedure  500  implementing the ablation system  100  illustrated and described herein with respect to  FIG. 1 . In this example, the ablation applicator  400  illustrated and described herein with respect to  FIG. 4  is being applied about a pulmonic vein  502  of heart  504  in accordance with an aspect of the invention. For purposes of simplification of explanation, the same reference numbers will be used to identify parts previously introduced with respect to  FIGS. 1 and 4 . It to be understood that any of the ablation applicators  200 ,  300  and  400  illustrated and described herein could be used in a similar manner. 
         [0041]    In the ablation procedure, the ablation applicator  400  is applied adjacent a lower portion of a right inferior pulmonic vein  502 . In the present example, the ablation applicator  400  circumscribes at least a portion of the right inferior pulmonic vein  502 . It is to be appreciated that the ablation applicator  400  could be applied to other surfaces of the heart, and the present procedure  500  disclosed is but one example implementation. The ablation applicator  400  could be applied to the right inferior pulmonic vein  506  by, for example, a robotic or endoscopic technique. Alternatively, the applicator  400  can be applied manually. 
         [0042]    Initially, when the ablation applicator  400  is applied, the adjustable valve  106  of the ablation fluid source  102  can be set to the OFF position. Additionally, once ablation applicator  400  is in place, the suction source  124  can be activated. Activation of the suction source  124  creates an substantially airtight seal between the ablation applicator  400  and the ablation site (e.g., the heart tissue) around the right inferior pulmonic vein  506 . 
         [0043]    After a relatively short amount of time (e.g., 2-3 seconds), the adjustable valve  106  of the ablation fluid source  102  can be set to the ON position, allowing ablation fluid to flow. The ablation fluid flows from the ablation fluid source  102  to the input port  110  of the heater  104  via the lumen of the flexible tube  108 . Upon arriving at the heater  104 , the ablation fluid flows between the input port  110  an the output port  112  of the heater  104  via the lumen of the immersed tube. Upon leaving the heater  104  at the output port  112 , the ablation fluid is heated to approximately a predetermined temperature (e.g., 60-70 degrees Celsius). The heated ablation fluid flows from the output port  112  of heater  104  to the input port  418  of the ablation applicator  400  via the lumen of the connector tube  116 . 
         [0044]    In the present example, the temperature controller  120  can control the heater  118  to heat the fluid to a predetermined temperature. The heating element  118  is activated such that the heating liquid in the heater is at or near the predetermined temperature. The sensor  122  can monitor the temperature of ablation fluid in the ablation applicator  400  or the temperature of the application itself or the temperature of the ablation site, and the temperature controller  120  controls the intensity of the heating element  118  such as described herein with respect to  FIG. 1 . 
         [0045]    Once the heated ablation fluid is within the volume of the ablation applicator  400 , the heated ablation fluid directly contacts the myocardial ablation site adjacent the right inferior pulmonic vein  502 . The contact edge  416  of the ablation applicator  400  thus surrounds an area of the patient&#39;s heart muscle defining the ablation site. The suction source  124  will pull the heated ablation fluid through the ablation applicator  400  out the output port  420  of the ablation applicator  400  via the lumen of the output port  420 . The heated ablation fluid will continue to flow to the waste reservoir via the lumen of the suction tube  126 . When the heated ablation fluid is applied, tissue in contact with the heated ablation fluid (at the ablation site) will increase in temperature. Typically, the cells in such heated tissue are destroyed tissue will die once the tissue is heated to approximately 65 degrees Celsius. When a sufficient amount of tissue has been destroyed, the application of heeled ablation fluid can be turned to the OFF position, such as causing substantially all of the ablation fluid that has been released by the ablation fluid source  102  (both heated and unheated) to flow through the system  100  and into the waste reservoir. When the suction source  124  is deactivated, the ablation applicator  400  can be removed. It is to be understood that the activation and deactivation of the suction source  124  can selectively control flow of heated ablation fluid into and out of the ablation applicator  400 . 
         [0046]    What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.