Left atrial access apparatus and methods

Abstract

Left atrial access apparatus and methods are described herein. Different parameters, such as oxygen saturation difference, between the left and right atrial chambers is utilized to guide a needle or catheter into a desired position within the heart. Various sensing elements can be utilized to detect the physiological parameter difference, such as oxygen levels, in the left atrium. The sensor can be carried by the needle, at its tip or along its body, and can measure the physiological parameter levels contained in the blood, fluid, or tissue.

1 . An apparatus for detecting a physiological parameter, comprising: 
 a probe configured to pierce a tissue region of interest;    a sensor disposed near or at the distal end of the probe, the sensor being adapted to detect the physiological parameter; and    a guidewire connected to the probe and adapted to advance the sensor towards the tissue region of interest.    
     
     
         2 . The apparatus of  claim 1  further comprising a handle removably positioned on a proximal end of the guidewire for manipulating the guidewire.  
     
     
         3 . The apparatus of  claim 1  further comprising a detector in electrical communication with the sensor for detecting the physiological parameter.  
     
     
         4 . The apparatus of  claim 3  further comprising a user interface in electrical communication with the detector for indicating the physiological parameter to a user.  
     
     
         5 . The apparatus of  claim 1  further comprising a catheter advanceable over the guidewire towards the tissue region of interest.  
     
     
         6 . The apparatus of  claim 5  wherein the catheter comprises an end effector.  
     
     
         7 . The apparatus of  claim 1  wherein the probe comprises a needle body.  
     
     
         8 . The apparatus of  claim 7  wherein the needle body is at least partially hollow.  
     
     
         9 . The apparatus of  claim 7  wherein the needle body comprises a tapered distal end for piercing into or through the tissue region of interest.  
     
     
         10 . The apparatus of  claim 7  wherein the needle body comprises a 20-27 gauge needle.  
     
     
         11 . The apparatus of  claim 1  wherein the sensor is adapted to detect the physiological parameter selected from the group consisting of oxygen saturation, temperature, carbon dioxide concentration, blood pressure, blood velocity, pH, and combinations thereof.  
     
     
         12 . The apparatus of  claim 1  wherein the sensor comprises at least one optical fiber adapted to detect light reflections indicative of the physiological parameter from fluids or tissue within or adjacent to the tissue region of interest.  
     
     
         13 . The apparatus of  claim 1  wherein the sensor comprises at least one optical fiber adapted to detect a pressure change via a flexible membrane indicative of the physiological parameter from fluids or tissue within or adjacent to the tissue region of interest.  
     
     
         14 . The apparatus of  claim 1  wherein the sensor comprises at least one optical fiber adapted to detect fluorescence from a polymeric material indicative of the physiological parameter from fluids or tissue within or adjacent to the tissue region of interest.  
     
     
         15 . A method of locating a tissue region of interest for passage of an apparatus therethrough, comprising: 
 probing an area of tissue with a probe;    sensing a physiological parameter of the tissue while probing the area; and    piercing the tissue at least partially with the probe upon detecting a change in the sensed physiological parameter.    
     
     
         16 . The method of  claim 15  further comprising advancing the probe to the tissue region of interest within a mammalian heart prior to probing an area.  
     
     
         17 . The method of  claim 15  further comprising advancing the probe into a right atrial chamber of a heart prior to probing an area.  
     
     
         18 . The method of  claim 15  further comprising advancing a catheter over a guidewire towards the tissue region of interest, the guidewire being attached to a proximal end of the probe.  
     
     
         19 . The method of  claim 15  wherein probing an area of tissue comprises advancing the probe against, into, or through the area of tissue.  
     
     
         20 . The method of  claim 15  wherein probing an area of tissue comprises probing the tissue in a predetermined pattern.  
     
     
         21 . The method of  claim 15  wherein probing an area of tissue comprises probing an atrial septum.  
     
     
         22 . The method of  claim 15  wherein sensing a physiological parameter comprises sensing the parameter selected from the group consisting of oxygen saturation, temperature, carbon dioxide concentration, blood pressure, blood velocity, pH, and combinations thereof.  
     
     
         23 . The method of  claim 15  wherein sensing a physiological parameter comprises transmitting a light and measuring its reflectance as being indicative of the physiological parameter.  
     
     
         24 . The method of  claim 15  wherein sensing a physiological parameter comprises comparing a measurement from the probed area to a measurement from an area proximal of the probed area.  
     
     
         25 . The method of  claim 15  wherein sensing a physiological parameter comprises comparing a measurement from a left atrial chamber to a measurement from a right atrial chamber.  
     
     
         26 . The method of  claim 15  wherein piercing the tissue comprises advancing the probe at least partially into a left atrial chamber.