Cardiac catheter employing conformal electronics for mapping

Abstract

An apparatus for medical diagnosis and/or treatment is provided. The apparatus includes a flexible substrate, an intermediate bus disposed on the flexible substrate, and a plurality of sensing elements disposed on the flexible substrate and coupled to the intermediate bus. The plurality of sensing elements and intermediate bus are disposed on the flexible substrate such that the sensing elements are disposed at areas of minimal strain of the flexible substrate.

1 - 133 . (canceled) 
     
     
         134 . A cryoablation apparatus comprising:
 a flexible substrate forming an inflatable cryoballoon;   a shaft supporting the inflatable cryoballoon, the shaft including a channel for delivering a cryoablation fluid to the inflatable cryoballoon; and   a plurality of active electrical circuits disposed in an array on the inflatable cryoballoon, the plurality of active electrical circuits including at least one amplifier.   
     
     
         135 . The apparatus of  claim 134 , wherein one or more active electrical circuits of the plurality of active electrical circuits provide cryoablation therapy to tissue adjacent to the one or more active electrical circuits. 
     
     
         136 . The apparatus of  claim 135 , wherein one or more additional active electrical circuits of the plurality of active electrical circuits provide drug administration to the tissue. 
     
     
         137 . The apparatus of  claim 134 , wherein the plurality of active electrical circuits include at least one of a pressure sensing element, a temperature sensing element, or an electrode. 
     
     
         138 . The apparatus of  claim 137 , wherein the electrode is a bipole electrode, an intracardiac electrogram (EGM) electrode, a recording electrode, or a radiofrequency (RF) electrode. 
     
     
         139 . The apparatus of  claim 134 , wherein at least one active electrical circuit of the plurality of active electrical circuits includes at least one electrode, and the at least one amplifier includes at least one differential pair amplifier coupled to the at least one electrode. 
     
     
         140 . The apparatus of  claim 139 , wherein the at least one differential pair amplifier includes a pair of transistors connected to a common source. 
     
     
         141 . The apparatus of  claim 134 , wherein the plurality of active electrical circuits includes two electrodes coupled to at least one differential pair amplifier. 
     
     
         142 . The apparatus of  claim 134 , wherein the plurality of active electrical circuits includes at least one electrode and at least one source-follower amplifier coupled to the at least one electrode. 
     
     
         143 . The apparatus of  claim 142 , wherein the at least one source-follower amplifier is coupled to at least one pass-through switch. 
     
     
         144 . The apparatus of  claim 142 , wherein the at least one electrode is coupled to a gate of the at least one source-follower amplifier. 
     
     
         145 . The apparatus of  claim 142 , wherein at least one active electrical circuit of the plurality of active electrical circuits includes at least one differential pair amplifier coupled to the at least one electrode. 
     
     
         146 . The apparatus of  claim 134 , wherein the plurality of active electrical circuits includes an array of amplifiers distributed across the inflatable cryoballoon. 
     
     
         147 . The apparatus of  claim 134 , wherein one or more measurements of the plurality of active electrical circuits indicates an amount of contact between the inflatable cryoballoon and tissue. 
     
     
         148 . The apparatus of  claim 147 , wherein one or more measurements from the plurality of active electrical circuits indicates an arrhythmia condition of the tissue. 
     
     
         149 . The apparatus of  claim 147 , wherein one or more measurements from the plurality of active electrical circuits indicates an atrial fibrillation or a ventricular fibrillation of the tissue. 
     
     
         150 . The apparatus of  claim 147 , wherein one or more measurements of the plurality of active electrical circuits provides a spatial mapping and/or a temporal mapping of an arrhythmia associated with the tissue. 
     
     
         151 . The apparatus of  claim 134 , further comprising:
 at least one intermediate bus connected to the flexible substrate,   wherein each active electrical circuit of the plurality of active electrical circuits is electrically coupled to the at least one intermediate bus.   
     
     
         152 . The apparatus of  claim 151 , wherein a portion of the at least one intermediate bus is disposed about a distal region of the inflatable cryoballoon, and the plurality of active electrical circuits is disposed proximate to the distal region of the inflatable cryoballoon. 
     
     
         153 . A cryoablation apparatus comprising:
 a flexible substrate forming an inflatable cryoballoon;   a shaft supporting the inflatable cryoballoon, the shaft including a channel for delivering a cryoablation fluid to the inflatable cryoballoon; and   a plurality of active electrical circuits disposed on the inflatable cryoballoon, the plurality of active electrical circuits being configured to transmit one or more multiplexed signals to at least one signal processor, at least one active electrical circuit of the plurality of active electrical circuits comprising:   at least one electrode; and   at least one source-follower amplifier coupled to the at least one electrode,   wherein the inflatable cryoballoon is conformable to a contour of a surface to be measured.   
     
     
         154 . The apparatus of  claim 153 , wherein each active electrical circuit of the plurality of active electrical circuits is coupled to at least one adjacent active electrical circuit of the plurality of active electrical circuits by at least one conductive flexible interconnection. 
     
     
         155 . The apparatus of  claim 153 , wherein at least one active electrical circuit of the plurality of active electrical circuits includes at least one pass-through switch, and the at least one source-follower amplifier is coupled to the at least one pass-through switch. 
     
     
         156 . The apparatus of  claim 155 , wherein the at least one source-follower amplifier is an input transistor having a drain coupled to a ground, and the at least one pass-through switch is a pass-through transistor coupled to the input transistor. 
     
     
         157 . The apparatus of  claim 156 , wherein a source of the input transistor is coupled to a drain of the pass-through transistor. 
     
     
         158 . The apparatus of  claim 156 , wherein the input transistor and the pass-through transistor are NMOS transistors. 
     
     
         159 . A method of cryoablating tissue, the method comprising:
 positioning a cryoballoon with respect to the tissue, wherein the cryoballoon includes a flexible substrate, a shaft supporting the flexible substrate, and a plurality of active electrical circuits disposed in an array on the inflatable cryoballoon, the plurality of active electrical circuits including at least one amplifier;   energizing one or more active electrical circuits of the plurality of active electrical circuits to generate one or more measurements of a state of the tissue;   amplifying the one or more measurements with the at least one amplifier; and   delivering a cryothermal fluid to the cryoballoon through the shaft to provide cryothermal energy to the tissue based on the one or more amplified measurements.   
     
     
         160 . The method of  claim 159 , further comprising:
 inflating the cryoballoon after positioning the cryoballoon with respect to the tissue;   energizing one or more active electrical circuits to determine a contact state of the inflated cryoballoon relative to the tissue; and   causing visualization on a user interface of a representation of the contact state of the inflated cryoballoon.   
     
     
         161 . The method of  claim 160 , wherein the representation of the contact state provides a quantitative representation of contact between the cryoballoon and the tissue. 
     
     
         162 . The method of  claim 160 , wherein the tissue is a blood vessel, and the inflating of the cryoballoon occludes blood flow through the blood vessel prior to delivering the cryothermal fluid. 
     
     
         163 . The method of  claim 160 , further comprising:
 re-energizing one or more active electrical circuits of the plurality of active electrical circuits to generate one or more additional measurements of a subsequent state of the tissue;   amplifying the one or more additional measurements with the at least one amplifier; and determining an efficacy of cryoablating the tissue based on the one or more amplified additional measurements.