Systems, devices, and methods for focal ablation

Abstract

Systems, devices, and methods for electroporation ablation therapy are disclosed, with the device including a set of splines coupled to a catheter for medical ablation therapy. Each spline of the set of splines may include a set of electrodes formed on that spline. The set of splines may be configured for translation to transition between a first configuration and a second configuration. The devices described herein may be used to form a lesion via focal ablation.

We claim: 
     
         1 . A method of ablating via irreversible electroporation, the method comprising:
 translating, when an ablation device is positioned in a cardiac chamber of a heart of a subject, an inner shaft of the ablation device relative to an outer shaft of the ablation device to transition a set of splines of the ablation device into a deployed state in which a distal portion of each spline of the set of splines and a proximal portion of each spline of the set of splines are set at an angle of less than 90 degrees with respect to each other, each spline from the set of splines having a distal end coupled to the inner shaft and a proximal end coupled to the outer shaft, each spline from the set of splines including a proximal electrode and a distal electrode;   generating a voltage pulse waveform using a signal generator; and   delivering, independently of an orientation of the set of splines relative to the target area, the voltage pulse waveform to a subset of proximal and distal electrodes such that the subset of proximal and distal electrodes collectively generate an electric field that ablates the target area via irreversible electroporation, the electric field having an electric field intensity of at least about 200 V/cm in the target area being ablated.   
     
     
         2 . The method of  claim 1 , wherein the voltage pulse waveform is delivered to the proximal and distal electrodes via a set of insulated electrical leads coupled to the proximal and distal electrodes,
 each proximal and distal electrode coupled to a different insulated electrical lead from the set of insulated electrical leads,   each insulated electrical lead from the set of insulated electrical leads configured to sustain a voltage potential of at least about 700 V without dielectric breakdown.   
     
     
         3 . The method of  claim 2 , wherein each spline from the set of splines includes a tubular body that houses the insulated electrical leads associated with the proximal and distal electrodes formed on that spline. 
     
     
         4 . The method of  claim 1 , wherein each spline from the set of splines includes a tubular body, the proximal and distal electrodes formed on each spline from the set of splines are metallic rings disposed about the tubular body of that spline. 
     
     
         5 . The method of  claim 1 , wherein the set of splines in the deployed state are positionable at a plurality of different orientations relative to the tissue, the method further comprising:
 configuring, when the set of splines are positioned at any one of the plurality of different orientations, the distal electrodes of a first subset of splines as anodes and the proximal electrodes of a second subset of splines as cathodes,   the voltage pulse waveform being delivered to the proximal and distal electrodes of the respective first and second subsets of splines such that the proximal and distal electrodes of the subset of splines act as anode-cathode pairs to generate the electric field.   
     
     
         6 . An apparatus positionable in a cardiac chamber of a heart for ablating tissue via irreversible electroporation, the apparatus comprising:
 a first shaft defining a longitudinal axis and a lumen; and   a second shaft disposed within the lumen and having a distal portion that extends from a distal end of the first shaft;   a plurality of electrodes;   a set of splines, each spline of the set of splines including:
 a set of electrodes from the plurality of electrodes formed on that spline, each set of electrodes including (1) a distal electrode such that the set of splines includes a set of distal electrodes and (2) a proximal electrode such that the set of splines includes a set of proximal electrodes; 
 a proximal end coupled to the first shaft; and 
 a distal end coupled to the second shaft, 
   the set of splines transitionable into a deployed state in which the set of splines is positionable in a plurality of different orientations relative to the tissue, a pre-selected portion of the plurality of electrodes activatable in the deployed state in any one of the plurality of different orientations to generate an electric field for ablating tissue via irreversible electroporation independent of the orientation of the set of splines, the electric field having an electric field intensity of at least about 200 V/cm.   
     
     
         7 . The apparatus of  claim 6 , wherein each spline from the set of splines includes a tubular body, the distal and proximal electrodes of that spline being ring electrodes that are disposed about the tubular body. 
     
     
         8 . The apparatus of  claim 6 , wherein each spline from the set of splines includes a tubular body,
 each spline from the set of splines further including a set of insulated electrical leads disposed within the tubular body, the proximal and distal electrodes of each spline coupled to different insulated electrical leads from the set of insulated electrical leads,   each insulated electrical lead from the set of insulated electrical leads configured to sustain a voltage potential of at least about 700 V without dielectric breakdown.   
     
     
         9 . The apparatus of  claim 6 , wherein each spline from the set of splines includes a tubular body,
 each spline from the set of splines bowing outwardly from the second shaft spaced from adjacent splines such that central portions of the tubular bodies of the set of splines are spaced from one another.   
     
     
         10 . The apparatus of  claim 6 , wherein, when the set of splines are in the deployed state, a distal portion of each spline of the set of splines and a proximal portion of each spline of the set of splines are set at an angle of about 70 degree to about 120 degrees with respect to each other. 
     
     
         11 . The apparatus of  claim 6 , wherein a distal end of the second shaft is separated from each distal electrode from the set of distal electrodes by the same distance, the distance being at most about 6 mm. 
     
     
         12 . An apparatus positionable in a cardiac chamber of a heart for ablating tissue via irreversible electroporation, the apparatus comprising:
 a first shaft defining a longitudinal axis and a lumen; and   a second shaft disposed within the lumen and having a distal portion that extends from a distal end of the first shaft;   a plurality of electrodes; and   a set of splines, each spline of the set of splines including:
 a set of electrodes from the plurality of electrodes formed on that spline, each set of electrodes including (1) a distal electrode such that the set of splines includes a set of distal electrodes and (2) a proximal electrode such that the set of splines includes a set of proximal electrodes; 
 a proximal end coupled to the first shaft; and 
 a distal end coupled to the second shaft, 
   the set of splines transitionable into a plurality of states between and inclusive of an undeployed configuration and an expanded configuration in which an angle between a first unit tangent vector extending through a length of a distal portion of each spline from the set of splines and a second unit tangent vector extending through a proximal portion of each spline from the set of splines varies between about 70 degrees and about 180 degrees,   a pre-selected portion of the plurality of electrodes activatable in each of the plurality of states to generate an electric field having an electric field intensity of at least about 200 V/cm for ablating tissue via irreversible electroporation.   
     
     
         13 . The apparatus of  claim 12 , wherein the set of splines, when used to ablate cardiac tissue, is transitioned into one or more states from the plurality of states in which the angle is between about 90 degrees and about 180 degrees. 
     
     
         14 . The apparatus of  claim 12 , wherein the set of splines, when used to ablate cardiac tissue, is transitioned into one or more states from the plurality of states in which the angle is between about 70 degrees and about 120 degrees. 
     
     
         15 . The apparatus of  claim 12 , wherein each electrode of the plurality of electrodes has an insulated electrical lead associated therewith, the insulated electrical leads configured to convey a pulse waveform to the pre-selected portion of the plurality of electrodes in each of the plurality of states to activate the electrodes and generate the electric field, the insulated electrical leads configured to sustain a voltage potential of at least about 700 V without dielectric breakdown. 
     
     
         16 . The apparatus of  claim 15 , wherein each spline from the set of splines includes a tubular body that houses the insulated electrical leads associated with the set of electrodes formed on that spline. 
     
     
         17 . The apparatus of  claim 12 , wherein the set of splines is transitionable into the plurality of states in response to the second shaft moving relative to the first shaft along the longitudinal axis. 
     
     
         18 . The apparatus of  claim 12 , wherein a distal end of the second shaft is separated from each distal electrode from the set of distal electrodes by the same distance, the distance being at must about 6 mm.