Methods and apparatus for treatment of atrial fibrillation

Abstract

Apparatus and methods for the treatment of atrial fibrillation are described herein where tissue to be ablated may be monitored under direct visualization. Such a system may include a deployment catheter and an attached imaging hood deployable into an expanded configuration. In use, the imaging hood is placed against or adjacent to the tissue to be imaged in a body lumen that is normally filled with an opaque bodily fluid such as blood. A translucent or transparent fluid can be pumped into the imaging hood until the fluid displaces any blood leaving a clear region of tissue to be imaged via an imaging element in the deployment catheter. An ablation probe may be advanced into the contained region where the tissue may be ablated and monitored for changes in color as well as appropriate positioning.

1 . A tissue imaging and treatment system, comprising: 
 a deployment catheter defining at least one lumen therethrough;    a barrier or membrane projecting distally from the deployment catheter and defining an open area therein, wherein the open area is in fluid communication with the at least one lumen;    a visualization element disposed within or along the barrier or membrane for visualizing tissue adjacent to the open area; and    an ablation energy transmitting surface positionable to ablate tissue adjacent to or contained within the open area.    
   
   
       2 . The system of  claim 1  further comprising a delivery catheter through which the deployment catheter is deliverable.  
   
   
       3 . The system of  claim 1  wherein the deployment catheter is steerable.  
   
   
       4 . The system of  claim 3  wherein the deployment catheter is steered via pulling at least one wire.  
   
   
       5 . The system of  claim 3  wherein the deployment catheter is steered via computer control.  
   
   
       6 . The system of  claim 1  wherein the barrier or membrane is comprised of a compliant material.  
   
   
       7 . The system of  claim 1  wherein the barrier or membrane defines a peripheral contact edge for placement against a tissue surface so that the tissue surface spans along and within the contact edge, wherein the energy transmitting surface comprises an electrode electrically coupleable to the tissue surface span for ablating the visualized tissue.  
   
   
       8 . The system of  claim 1  wherein the barrier or membrane is adapted to be reconfigured from a low-profile delivery configuration to an expanded deployed configuration.  
   
   
       9 . The system of  claim 8  wherein the barrier or membrane is adapted to self-expand into the expanded deployed configuration.  
   
   
       10 . The system of  claim 8  wherein the barrier or membrane comprises one or more support struts along the barrier or membrane.  
   
   
       11 . The system of  claim 1  wherein the barrier or membrane is conically shaped.  
   
   
       12 . The system of  claim 1  wherein the visualization element comprises at least one optical fiber, CCD imager, or CMOS imager.  
   
   
       13 . The system of  claim 1  wherein the visualization element is disposed within a distal end of the deployment catheter.  
   
   
       14 . The system of  claim 1  wherein the visualization element is articulatable off-axis relative to a longitudinal axis of the deployment catheter.  
   
   
       15 . The system of  claim 1  further comprising a fluid reservoir fluidly coupled to the barrier or membrane.  
   
   
       16 . The system of  claim 15  wherein the fluid comprises saline, plasma, water, or perfluorinated liquid.  
   
   
       17 . The system of  claim 1  wherein the barrier or membrane further comprises a distal membrane extending over the open area such that the energy transmitting surface comprises an ablation electrode circumferentially disposed over the distal membrane.  
   
   
       18 . The system of  claim 1  wherein the barrier or membrane further comprises a distal membrane extending radially inwardly near a distal edge of the barrier or membrane partially over the open area such that the distal membrane defines an aperture through which the ablation electrode is extendable.  
   
   
       19 . The system of  claim 1  wherein the energy transmitting surface comprises an ablation electrode, and wherein the ablation electrode is articulatable.  
   
   
       20 . The system of  claim 1  wherein the energy transmitting surface comprises an ablation electrode, and wherein the ablation electrode comprises a monopolar or bipolar radio-frequency electrode.  
   
   
       21 . The system of  claim 1  wherein the energy transmitting surface is reconfigurable from a first linear profile to a second extended profile.  
   
   
       22 . The system of  claim 21  wherein the second extended profile defines a linear configuration transverse relative to a longitudinal axis of the deployment catheter.  
   
   
       23 . The system of  claim 21  wherein the energy transmitting surface is contained within a linear housing which is articulatable between a linear profile and an expanded Y-shaped profile.  
   
   
       24 . The system of  claim 21  wherein the second extended profile defines a circular configuration.  
   
   
       25 . The system of  claim 1  wherein the energy transmitting surface is circumferentially disposed over a contact lip or edge of the barrier or membrane.  
   
   
       26 . The system of  claim 1  wherein the ablation probe comprises a plurality of needles.  
   
   
       27 . The system of  claim 26  wherein the plurality of needles is extendable from a retracted configuration into an ablation configuration.  
   
   
       28 . The system of  claim 1  further comprising an occlusion balloon which is expandable into an inflated shape sufficiently sized to occlude a vessel lumen.  
   
   
       29 . The system of  claim 1  further comprising a first articulatable tissue grasper positioned upon a first support member extending distally from the barrier or membrane.  
   
   
       30 . The system of  claim 29  further comprising a second articulatable tissue grasper positioned upon a second support member extending distally from the barrier or membrane, wherein the second tissue grasper is articulatable independently of the first tissue grasper.  
   
   
       31 . The system of  claim 29  further comprising a length of wire or suture slidably passed through the tissue grasper, wherein a first end of the wire or suture is attached to the tissue imaging and treatment system and a second end of the wire or suture is pulled from outside a patient body.  
   
   
       32 . The system of  claim 1  further comprising an intra-atrial balloon disposed upon a distal end of the catheter, wherein the balloon is expandable from a low-profile deflated configuration to an inflated configuration.  
   
   
       33 . The system of  claim 32  wherein the inflated configuration occupies up to 75% or more of volume of an atrial chamber within a patient heart.  
   
   
       34 . The system of  claim 32  wherein the intra-atrial balloon comprises one or more radio-opaque markers.  
   
   
       35 . A tissue imaging and treatment system for treating a tissue region within a heart, the heart having a chamber, the chamber including a tissue surface and containing blood, the system comprising: 
 a catheter body having a lumen;    a visualization element disposed adjacent the catheter body, the visualization element having a field of view;    a translucent fluid source in fluid communication with the lumen; and    a barrier or membrane extendable from the catheter body to localize, between the visualization element and the field of view, displacement of blood by translucent fluid that flows from the lumen; and    an ablation energy transmitting surface positionable for ablating the tissue within the field of view.    
   
   
       36 . The system of  claim 35  wherein the membrane or barrier is disposed about an open area between the visualization element and the field of view, the fluid source configured to inject translucent fluid so as to displace the blood from the open area sufficiently to allow optical imaging of the tissue surface though the open area while the heart is beating.  
   
   
       37 . The system of  claim 36  wherein the membrane is expandable from a low-profile delivery configuration to an expanded configuration to encompass an imaged tissue surface larger than a cross-section of the catheter.  
   
   
       38 . The system of  claim 37  further comprises a frame supporting the membrane outside of the open area in the expanded configuration.  
   
   
       39 . The system of  claim 38  wherein the frame comprises a shape memory alloy, and wherein the visualization element is supported by the frame.  
   
   
       40 . The system of  claim 35  wherein the barrier or membrane comprises a hood, the barrier or membrane having a contact edge surrounding an aperture adjacent the field of view so that, during use, transparent fluid from the lumen is released into the chamber of the heart through the aperture, wherein the energy transmitting surface is translatable through the aperture.  
   
   
       41 . The system of  claim 35  wherein the barrier or membrane has an inner surface and an outer surface, a volume disposed within the inner surface being greater than a volume disposed between the inner surface and the outer surface.  
   
   
       42 . The system of  claim 35  wherein the catheter body is included in a steerable catheter, the steerable catheter having an elongate proximal portion and an articulable section adjacent the barrier, the steerable section comprising a plurality of links and steerable from a proximal end of the proximal portion so as to impose a smooth axial curvature on the catheter body.  
   
   
       43 . The system of  claim 35  wherein the catheter body has a working lumen slidably receiving the energy transmitting surface, a lumen for receiving a steering element to laterally deflect the catheter body, a translucent fluid flow lumen, and an image conduit for transmitting images of the tissue surface from the visualization element.  
   
   
       44 . The system of  claim 35  wherein the barrier or membrane further comprises a distal membrane extending partially over the open area such that the distal membrane defines an aperture through which the energy transmitting surface is extendable.  
   
   
       45 . The system of  claim 35  wherein the energy transmitting surface comprises an articulatable ablation electrode.  
   
   
       46 . The system of  claim 35  wherein the energy transmitting surface comprises a monopolar or bipolar radio-frequency electrode.  
   
   
       47 . The system of  claim 35  wherein the energy transmitting surface comprises a plurality of needles.  
   
   
       48 . The system of claim.  47  wherein the plurality of needles is extendable from a retracted configuration into an ablation configuration.  
   
   
       49 . The system of  claim 35  further comprising an occlusion balloon which is expandable into an inflated shape sufficiently sized to occlude a vessel lumen.  
   
   
       50 . The system of  claim 35  further comprising a first articulatable tissue grasper positioned upon a first support member extending distally from the barrier or membrane.  
   
   
       51 . The system of  claim 50  further comprising a second articulatable tissue grasper positioned upon a second support member extending distally from the barrier or membrane, wherein the second tissue grasper is articulatable independently of the first tissue grasper.  
   
   
       52 . The system of  claim 50  further comprising a length of wire or suture slidably passed through the tissue grasper, wherein a first end of the wire or suture is attached to the tissue imaging and treatment system and a second end of the wire or suture is pulled from outside a patient body.  
   
   
       53 . A method for intravascularly treating a tissue region within a body lumen, comprising: 
 positioning an open area of a barrier or membrane against or adjacent to the tissue region to be treated;    displacing an opaque bodily fluid with a translucent fluid from an open area defined by the barrier or membrane and the tissue region;    visualizing the tissue region within the open area through the translucent fluid; and    ablating at least a portion of the tissue region within the open area.    
   
   
       54 . The method of  claim 53  wherein positioning an open area of a barrier or membrane comprises advancing the barrier or membrane into a left atrial chamber of a heart.  
   
   
       55 . The method of  claim 53  wherein positioning an open area of a barrier or membrane comprises deploying the barrier or membrane from a low-profile delivery configuration into an expanded deployed configuration.  
   
   
       56 . The method of  claim 53  wherein positioning an open area of a barrier or membrane comprises stabilizing a position of the barrier or membrane relative to the tissue region.  
   
   
       57 . The method of  claim 53  wherein positioning an open area of a barrier or membrane comprises steering the deployment catheter to the tissue region.  
   
   
       58 . The method of  claim 53  wherein displacing an opaque bodily fluid with a translucent fluid comprises infusing the translucent fluid into the open area through a fluid delivery lumen defined through the deployment catheter.  
   
   
       59 . The method of  claim 58  wherein infusing the translucent fluid comprises pumping saline, plasma, water, or perfluorinated liquid into the open area such that blood is displaced from therefrom.  
   
   
       60 . The method of  claim 53  wherein displacing an opaque bodily fluid with a translucent fluid comprises partially retaining the fluid within the open area via at least one transparent distal membrane disposed at least partially over a distal end of the barrier or membrane.  
   
   
       61 . The method of  claim 60  wherein partially retaining the fluid comprises allowing the fluid to leak through at least one aperture defined through the distal membrane.  
   
   
       62 . The method of  claim 61  wherein ablating comprises ablating the tissue region through the at least one aperture.  
   
   
       63 . The method of  claim 53  wherein visualizing the region of tissue comprises viewing the tissue via an imaging element positioned off-axis relative to a longitudinal axis of the barrier or membrane.  
   
   
       64 . The method of  claim 53  wherein ablating comprises contacting the tissue region with an ablation probe advanced through the open area.  
   
   
       65 . The method of  claim 64  further comprising articulating the ablation probe within the open area.  
   
   
       66 . The method of  claim 53  wherein ablating comprises forming a linear or circular lesion upon the tissue region.  
   
   
       67 . The method of  claim 53  further comprising occluding a blood flow through a pulmonary vein via an occlusion balloon inflated within the pulmonary vein distal to the barrier or membrane prior to ablating.  
   
   
       68 . The method of  claim 53  further comprising temporarily engaging a first and second tissue region in an alternating manner such that the barrier or membrane is moved from a first location to a second location through the body lumen prior to displacing an opaque bodily fluid.  
   
   
       69 . The method of  claim 53  wherein ablating comprises advancing a plurality of ablation needles into the tissue region.  
   
   
       70 . The method of  claim 53  further comprising visually monitoring the tissue region for changes in color while ablating as an indication of sufficient tissue ablation.  
   
   
       71 . The method of  claim 53  further comprising visually monitoring the tissue region for indications of endocardiac disruptions.  
   
   
       72 . The method of  claim 71  wherein if an endocardiac disruption is detected, adjusting a power of an ablation probe or ceasing ablating the tissue region.  
   
   
       73 . The method of  claim 72  further comprising further visually inspecting the tissue region.  
   
   
       74 . The method of  claim 71  wherein if an endocardiac disruption occurs, containing any tissue debris released from the disruption within the barrier or membrane.  
   
   
       75 . The method of  claim 74  further comprising suctioning the tissue debris contained within the barrier or membrane proximally through the deployment catheter.  
   
   
       76 . The method of  claim 53  further comprising drawing the tissue region within the open area at least partially into the barrier or membrane to create a seal between therebetween.  
   
   
       77 . The method of  claim 76  wherein ablating comprises ablating the sealed tissue region within the open area.  
   
   
       78 . The method of  claim 53  further comprising visually inspecting a lesion formed upon the tissue region within the open area.  
   
   
       79 . The method of  claim 78  further comprising repositioning the barrier or membrane upon a second tissue region to treated.  
   
   
       80 . A method for treating a target tissue of a heart of a patient, the target tissue underlying an intracardiac heart tissue surface region within a chamber of the heart, the method comprising: 
 optically imaging the tissue surface region;    ablating the target tissue; and    monitoring tissue response to the ablation using the optical imaging while the heart is pumping blood.    
   
   
       81 . The method of  claim 80  the heart of the patient having an arrhythmia, wherein the optical imaging provides a system user sufficient feedback to verify coupling between an energy transmitting surface and the tissue surface region during formation of an ablation lesion such that the lesion inhibits the arrhythmia.  
   
   
       82 . The method of  claim 81  wherein the energy delivery surface comprises an electrode surface, and wherein the system user can induce movement of the electrode surface or interrupts lesion formation in response to loss of contact between the target tissue and the electrode surface during formation of the lesion.  
   
   
       83 . The method of  claim 81  wherein the optical imaging feedback provided to the system user during formation of the lesion comprises changes in color along the tissue surface region, lesion-formation induced deformation along the tissue surface region, vaporization adjacent the tissue surface region, formation of bubbles adjacent the tissue surface region, positioning of the energy transmitting surface, movement of the energy transmitting surface, and/or ablation debris.  
   
   
       84 . The method of  claim 80  the heart of the patient having an arrhythmia, wherein the target tissue comprises an elongate lesion pattern, and wherein the optical imaging provides a system user sufficient feedback to verify contiguity along a length of the lesion pattern such that the lesion pattern inhibits propagation of the arrhythmia.  
   
   
       85 . The method of  claim 84  wherein the lesion pattern comprises a plurality of discrete ablation lesions formed sequentially in the target tissue, and wherein a movement of an energy transmitting surface from alignment with a first portion of the target tissue to a second portion of the target tissue is performed using optical feedback from the tissue response along a first discrete lesion associated with the first region of the target tissue.  
   
   
       86 . The method of  claim 84  wherein the lesion pattern is formed by moving an energy transmitting surface relative to the tissue surface region while transmitting energy from the energy transmitting surface to the target tissue, and wherein the movement is performed using optical feedback on progress of the tissue response along the length of the lesion pattern.  
   
   
       87 . The method of  claim 84  wherein the optical imaging feedback provided to the system user during formation of the lesion comprises changes in color along the tissue surface region, lesion-formation induced deformation along the tissue surface region, vaporization adjacent the tissue surface region, formation of bubbles adjacent the tissue surface region, positioning of the energy transmitting surface, movement of the energy transmitting surface, and/or ablation debris.  
   
   
       88 . The method of  claim 80  further comprising interrupting the ablating of the target tissue during the ablation in response to optical indicia of a potential tissue surface disruption, wherein the ablation is interrupted prior to embolization of ablation debris or bursting along the tissue surface region.  
   
   
       89 . The method of  claim 81  further comprising cooling the imaged tissue surface region during the imaging and the ablation.  
   
   
       90 . The method of  claim 80  wherein the tissue surface region is imaged by locally displacing blood from an imaging volume within the chamber of the heart.  
   
   
       91 . The method of  claim 90  wherein the translucent fluid comprises a transparent fluid, wherein the chamber of the heart pumps blood disposed around the imaging volume, and wherein-the transparent fluid is in contact with the tissue surface region.  
   
   
       92 . The method of  claim 91  wherein the transparent fluid flows along the tissue surface region so as to purge blood from between the energy transmitting surface and the tissue surface region.  
   
   
       93 . The method of  claim 92  wherein the transparent fluid cools the tissue surface region.  
   
   
       94 . The method of  claim 91  further comprising introducing a barrier or membrane into the chamber, expanding the barrier or membrane within the chamber, and limiting intrusion of the blood from within the chamber into the imaging volume with the barrier or membrane during the imaging.  
   
   
       95 . The method of  claim 80  wherein the optical imaging is performed so as to image a plurality of anatomical landmarks, and further comprising aligning the energy delivery surface with the target tissue in response to an image of one or more of the imaged landmarks.  
   
   
       96 . The method of  claim 80  wherein the anatomical landmarks comprise a pulmonary vein, an ostium of the pulmonary vein, a left atrial septum, a left atrial appendage, a mitral valve, a tricuspid valve, a fossa ovalis and a right atrial appendage.  
   
   
       97 . A system for treating a target tissue of the heart of a patient, the target tissue underlying an intracardiac heart tissue surface region within a chamber of the heart, the method comprising: 
 an intracardiac catheter having a proximal end, a distal end, and at least one lumen;    an optical imaging element advanceable distally using the catheter into the chamber of the heart;    an energy transmitting surface advanceable distally using the catheter into alignment with the tissue surface region for ablation of the target tissue; and    an imaging fluid flow path extendable distally from a translucent fluid source, through the catheter, and toward the tissue surface region, the extended flow path encompassing the optical imaging element and the aligned energy transmitting surface so as to inhibiting persistence of blood within a field of view of the imaging element when optically directing the ablation while the heart is pumping the blood.