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 - 50 . (canceled) 
     
     
         51 . An apparatus for generating one or more multiplexed signals, the apparatus comprising:
 a flexible substrate; and   a plurality of active electrical circuits coupled to the flexible substrate, each active electrical circuit in the plurality of active electrical circuits coupled to at least one adjacent active electrical circuit in the plurality of active electrical circuits via at least one conductive flexible interconnection, the plurality of active electrical circuits configured to transmit one or more multiplexed signals to at least one signal processor.   
     
     
         52 . The apparatus of  claim 51 , wherein one or more of the active electrical circuits in the plurality of active electrical circuits includes at least one electrode. 
     
     
         53 . The apparatus of  claim 51 , wherein one or more of the active electrical circuits in the plurality of active electrical circuits includes at least one multiplexing transistor. 
     
     
         54 . The apparatus of  claim 51 , one or more of the active electrical circuits in the plurality of active electrical circuits includes at least one amplifier. 
     
     
         55 . The apparatus of  claim 51 , wherein one or more of the active electrical circuits in the plurality of active electrical circuits includes at least one current mirror. 
     
     
         56 . The apparatus of  claim 51 , wherein the current mirror is switchable between an off state and an on state. 
     
     
         57 . The apparatus of  claim 51 , wherein one or more of the active electrical circuits in the plurality of active electrical circuits includes at least one current limiting resistor. 
     
     
         58 . The apparatus of  claim 51 , wherein the plurality of active electrical circuits are positioned in a plurality of arrays on the flexible substrate. 
     
     
         59 . The apparatus of  claim 58 , wherein the at least one signal processor is configured to receive a multiplexed signal from each active circuit. 
     
     
         60 . The apparatus of  claim 51 , wherein the substrate is stretchable. 
     
     
         61 . The apparatus of  claim 51 , wherein the substrate is elastic. 
     
     
         62 . The apparatus of  claim 51 , wherein the conductive flexible interconnection is buckled. 
     
     
         63 . The apparatus of  claim 51 , wherein the conductive flexible interconnection has a serpentine geometric configuration. 
     
     
         64 . The apparatus of  claim 51 , wherein the active electrical circuits includes one or more components selected from the group consisting of: a transistor, a resistor, a capacitor, an inductor, and a diode. 
     
     
         65 . The apparatus of  claim 51 , wherein at least one circuit in the plurality of active electrical circuits include at least one of, temperature sensor, a pressure sensor, a contact sensor, a conductivity sensor, a strain gauge, a complementary metal-oxide-semiconductor, metal oxide semiconductor field effect transistor, a light emitting diode, an electrode, a pH sensor, a chemical sensor, a biological sensor, and a calcium sensor. 
     
     
         66 . The apparatus of  claim 51 , wherein the plurality of active circuits are positioned in one or more arrays on the flexible substrate. 
     
     
         67 . The apparatus of  claim 51 , wherein the at least one processor is configured to construct a map of at least one physiological parameter by associating a portion of the multiplexed signal with one or more originating active electrical circuits in the plurality of active electrical circuits. 
     
     
         68 . The apparatus of  claim 51 , wherein the substrate has an active electrical circuit density of at least 64 circuits per cm 2 . 
     
     
         69 . The apparatus of  claim 51 , wherein the substrate has an active electrical circuit density ranging from 200 to 500 circuits per cm 2 . 
     
     
         70 . A method of generating one or more multiplexed signals, the method comprising: positioning a flexible substrate adjacent to an internal body surface, the flexible substrate having a plurality of active electrical circuits coupled thereto, each active electrical circuit in the plurality of active electrical circuits coupled to at least one adjacent active electrical circuit in the plurality of active electrical circuits via at least one conductive flexible interconnection;
 causing the substrate to move from a first configuration to a second configuration;   transmitting one or more multiplexed signals from the plurality of active electrical circuits to at least one signal processor; and   characterizing the at least one physiological parameter based on the multiplexed signal received by the signal processor.   
     
     
         71 - 98 . (canceled) 
     
     
         99 . An apparatus for readout of one or more multiplexed signals, the apparatus comprising:
 a flexible substrate; and   a plurality of active electrical circuits disposed on the substrate in a distributed arrangement, the plurality of active electrical circuits 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 differential pair amplifier coupled to the at least one electrode; wherein the plurality of active electrical circuits are disposed in a distributed arrangement on the substrate such that the apparatus is conformable to a contour of a surface to be measured.   
     
     
         100 . The apparatus of  claim 99 , wherein the flexible substrate is a portion of an inflatable body, and wherein the plurality of active electrical circuits are disposed at areas of minimal curvature of the inflatable body in the distributed arrangement. 
     
     
         101 . The apparatus of  claim 99 , 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 via at least one conductive flexible interconnection. 
     
     
         102 . The apparatus of  claim 99 , further comprising at least one conductive intermediate bus, wherein the at least one active electrical circuit of the plurality of active electrical is coupled to the at least one conductive intermediate bus. 
     
     
         103 . The apparatus of  claim 102 , wherein the plurality of active electrical circuits is configured to transmit one or more multiplexed signals to the at least one signal processor via the at least one conductive intermediate bus. 
     
     
         104 . The apparatus of  claim 99 , wherein the at least one active electrical circuit of the plurality of active electrical circuits further comprises a tail, and wherein the at least one differential pair amplifier is coupled to the tail. 
     
     
         105 . The apparatus of  claim 99 , wherein each of the active electrical circuit of the plurality of active electrical circuits comprises:
 at least one electrode; and   at least one differential pair amplifier coupled to the at least one electrode.   
     
     
         106 . The apparatus of  claim 105 , wherein each of the at least one differential pair amplifier comprises a pair of transistors whose sources are connected in a common connection to provide a common source. 
     
     
         107 . The apparatus of  claim 106 , wherein the pair of transistors are PMOS transistors. 
     
     
         108 . The apparatus of  claim 106 , wherein each of the transistors is connected in series with a current limiting resistor. 
     
     
         109 . The apparatus of  claim 106 , wherein each of the at least one differential pair amplifier is coupled to a tail. 
     
     
         110 . The apparatus of  claim 109 , wherein the tail is a transistor, and wherein the common source of the at least one differential pair amplifier is coupled to a drain of the tail. 
     
     
         111 . The apparatus of  claim 109 , wherein the gate of the tail is driven by a current-mirror. 
     
     
         112 . The apparatus of  claim 106 , wherein the at least one electrode is coupled to a gate of a transistor of the pair of transistors. 
     
     
         113 . The apparatus of  claim 106 , wherein the plurality of active electrical circuits are read in a row-column arrangement, wherein each row-column element of the row-column arrangement corresponds to at least one active electrical circuit of the plurality of active electrical circuits, and wherein a drain of a first transistor of the pair of transistors of each respective active electrical circuit is coupled to a column output of each respective row-column element. 
     
     
         114 . The apparatus of  claim 113 , wherein a second transistor of the pair of transistors of each respective active electrical circuit is coupled to a load resistor. 
     
     
         115 . The apparatus of  claim 113 , wherein all columns of the row-column arrangement are read substantially simultaneously, and wherein a single row of the row-column arrangement is active when the columns of the row-column arrangement are read. 
     
     
         116 . The apparatus of  claim 113 , wherein the drain of the first transistor of the pair of transistors of at least two active electrical circuits are coupled to the column output of each respective row-column element. 
     
     
         117 . The apparatus of  claim 106 , wherein each of the at least one differential pair amplifier of each active electrical circuit is coupled to a tail, and wherein each row input of the row-column arrangement is coupled to a gate of a tail of each active electrical circuit of the plurality of active electrical circuits. 
     
     
         118 . The apparatus of  claim 117 , wherein each row input of the row-column arrangement is coupled to a gate of a tail of each active electrical circuit of the plurality of active electrical circuits. 
     
     
         119 . The apparatus of  claim 99 , wherein the at least one active electrical circuit of the plurality of active electrical circuits comprises:
 two electrodes, and   a differential pair amplifier, wherein the two electrodes are coupled to the differential pair amplifier.   
     
     
         120 . The apparatus of  claim 119 , wherein the differential pair amplifier comprises a pair of transistors whose sources are connected in a common connection to provide a common source. 
     
     
         121 . The apparatus of  claim 120 , wherein each electrode is coupled to a gate of each transistor of the pair of transistors. 
     
     
         122 . The apparatus of  claim 121 , wherein a read-out of the at least one active electrical circuit is based on a differential of signals from the two electrodes. 
     
     
         123 . A method for readout of one or more multiplexed signals, the method comprising:
 disposing an apparatus proximate to a surface, the apparatus comprising: a plurality of active electrical circuits disposed on a flexible substrate in a distributed arrangement, the plurality of active electrical circuits configured to transmit one or more multiplexed signals to at least one signal processor, wherein at least one active electrical circuit of the plurality of active electrical circuits comprises:   an electrode;   a differential pair amplifier coupled to the electrode; and   a tail coupled to the differential pair amplifier, wherein the tail is coupled to a row control switch, wherein the differential pair amplifier is coupled to a column output, and wherein activating the row control switch activates the differential pair amplifier such that a signal from the electrode is transmitted to the column output;   applying a voltage to the row control switch; and   reading an output at the column output thereby providing the one or more multiplexed signals.   
     
     
         124 . The method of  claim 123 , wherein the plurality of active electrical circuits is coupled to a flexible substrate forming an inflatable body. 
     
     
         125 . The method of  claim 123 , 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 via at least one conductive flexible interconnection. 
     
     
         126 . The method of  claim 125 , further comprising transmitting the one or more multiplexed signals from the plurality of active electrical circuits to the at least one signal processor via the at least one conductive flexible interconnection. 
     
     
         127 . The method of  claim 123 , wherein the apparatus further comprises at least one conductive intermediate bus, wherein the at least one active electrical circuit of the plurality of active electrical is coupled to the at least one conductive intermediate bus. 
     
     
         128 . The method of  claim 127 , further comprising transmitting the one or more multiplexed signals from the plurality of active electrical circuits to the at least one signal processor via the at least one conductive intermediate bus. 
     
     
         129 . The method of  claim 123 , wherein the electrode is coupled to a first gate of the differential pair amplifier. 
     
     
         130 . The method of  claim 129 , wherein the apparatus further comprises a second electrode, and wherein a second gate of the differential pair amplifier is coupled to the second electrode. 
     
     
         131 . The method of  claim 129 , wherein the apparatus further comprises a second electrode, and wherein a second gate of the differential pair amplifier is biased to a ground potential. 
     
     
         132 . The method of  claim 123 , wherein the tail is coupled to the row control switch via a current-mirror, and wherein activating the row control switch biases the current-mirror, thereby activating the differential pair amplifier. 
     
     
         133 . The method of  claim 123 , wherein the at least one active electrical circuits comprises two active electrical circuits, wherein each of the two active electrical circuits is coupled to a respective row control switch, wherein the two active electrical circuits are coupled to a common column output, and wherein one of the row control switches is activated during the reading of the output from the common column output.