Systems and methods for mechanical mapping of cardiac rhythm

Abstract

Techniques for mapping behavior of a heart include acquiring a series of two or more images of the heart. The series of images is taken at one or more pixel locations, each pixel location corresponding to a region of the heart. Image data corresponding to the pixel locations can be obtained, and a periodicity of the image data measured for each of the pixel locations over the series of images. The periodicity corresponds to an electromechanical signal of the heart in the region corresponding to the measured one or more pixel locations.

1 . A method for mapping behavior of a heart, comprising:
 acquiring a series of two or more images of the heart, the series of images taken at one or more pixel locations, each pixel location corresponding to a region of the heart;   obtaining image data corresponding to the one or more pixel locations during the series of images; and   measuring, by an image processor, a periodicity of the image data for each of the one or more pixel locations over the series of images, the periodicity corresponding to an electromechanical signal of the heart in the region corresponding to the measured one or more pixel locations.   
     
     
         2 . The method of  claim 1 , wherein measuring the periodicity of the image data comprises measuring a peak frequency of the image data for each of the one or more pixel locations, the method further comprising determining a peak cycle length from each peak frequency, the peak cycle length corresponding to an electrical cycle length of the electromechanical signal of the heart in the region corresponding to the measured one or more pixel locations. 
     
     
         3 . The method of  claim 2 , further comprising measuring a phase associated with each peak frequency, the phase corresponding to a direction of propagation of the electromechanical signal in the heart. 
     
     
         4 . The method of  claim 1 , wherein measuring the periodicity comprises measuring a crossing of a threshold of the image data for each of the one or more pixel locations. 
     
     
         5 . The method of  claim 4 , wherein the threshold corresponds to a condition of zero strain at the region of the heart corresponding to the one or more pixel locations. 
     
     
         6 . The method of  claim 1 , wherein measuring the periodicity comprises performing a Fourier transform of the image data for each of the one or more pixel locations. 
     
     
         7 . The method of  claim 1 , wherein the image data comprises first image data corresponding to one or more first pixel locations corresponding to a first region of the heart and second image data corresponding to one or more second pixel locations corresponding to a second region of the heart, the method further comprising comparing a first periodicity corresponding to the first region and a second periodicity corresponding to the second region. 
     
     
         8 . The method of  claim 7 , further comprising measuring a first phase associated with the first periodicity and a second phase associated with the second periodicity, and comparing the first phase with the second phase to determine a direction of propagation of the electromechanical signal in the heart. 
     
     
         9 . The method of  claim 8 , wherein the first region of the heart comprises at least a portion of the right atrium and the second region of the heart comprises at least a portion of the left atrium or ventricles. 
     
     
         10 . The method of  claim 1 , further comprising, determining, by the imaging processor, a type of arrhythmia in the heart corresponding to the electromechanical signal. 
     
     
         11 . The method of  claim 10 , further comprising, estimating a likelihood of success of a treatment for the arrhythmia. 
     
     
         12 . The method of  claim 11 , wherein the treatment comprises ablation or cardioversion. 
     
     
         13 . An imaging system for mapping behavior of a heart, comprising:
 an imaging device configured to acquire a series of two or more images of the heart at one or more pixel locations, each pixel location corresponding to a region of the heart;   an image processor, coupled to the imaging device, configured to:
 obtain image data of the one or more pixel locations during the series of images, and 
 measure a periodicity of the image data for each of the one or more pixel locations over the series of images, the periodicity corresponding to an electromechanical signal of the heart in the region corresponding to the measured one or more pixel locations. 
   
     
     
         14 . The imaging system of  claim 13 , wherein the image processor is configured to measure the periodicity of the image data by measuring a peak frequency of the image data for each of the one or more pixel locations, the image processor being further configured to determine a peak cycle length from each peak frequency, the peak cycle length corresponding to an electrical cycle length of the electromechanical signal of the heart in the region corresponding to the measured one or more pixel locations. 
     
     
         15 . The imaging system of  claim 14 , wherein the image processor is further configured to measure a phase associated with each peak frequency, the phase corresponding to a direction of propagation of the electromechanical signal in the heart. 
     
     
         16 . The imaging system of  claim 13 , wherein the image processor is further configured to measure the periodicity by measuring a crossing of a threshold of the image data for each of the one or more pixel locations. 
     
     
         17 . The imaging system of  claim 16 , wherein the threshold corresponds to a condition of zero strain at the region of the heart corresponding to the one or more pixel locations. 
     
     
         18 . The imaging system of  claim 13 , wherein the image processor is further configured to measure the periodicity by performing a Fourier transform of the image data for each of the one or more pixel locations. 
     
     
         19 . The imaging system of  claim 13 , wherein the image data comprises an intensity of each of the one or more pixel locations. 
     
     
         20 . The imaging system of  claim 13 , wherein the imaging device comprises an ultrasound transducer. 
     
     
         21 . The imaging system of  claim 13 , wherein the image data comprises first image data corresponding to one or more first pixel locations corresponding to a first region of the heart and second image data corresponding to one or more second pixel locations corresponding to a second region of the heart, and the image processor is further configured to compare a first periodicity corresponding to the first region and a second periodicity corresponding to the second region. 
     
     
         22 . The imaging system of  claim 21 , wherein the image processor is further configured to compare a first phase associated with the first periodicity and a second phase associated with the second periodicity, and compare the first phase with the second phase to determine a direction of propagation of the electromechanical signal in the heart. 
     
     
         23 . The imaging system of  claim 22 , wherein the first region of the heart comprises at least a portion of the right atrium and the second region of the heart comprises at least a portion of the left atrium or ventricles. 
     
     
         24 . The imaging system of  claim 13 , wherein the imaging processor is further configured to determine a type of arrhythmia in the heart corresponding to the electromechanical signal. 
     
     
         25 . The imaging system of  claim 24 , wherein the imaging processor is further configured to estimate a likelihood of success of a treatment for the arrhythmia. 
     
     
         26 . The imaging system of  claim 25 , wherein the treatment comprises ablation or cardioversion. 
     
     
         27 . A method for planning and monitoring treatment of an arrhythmia, comprising:
 acquiring a series of two or more images of the heart, the series of images taken at one or more pixel locations, each pixel location corresponding to a region of the heart;   obtaining image data corresponding to the one or more pixel locations during the series of images;   measuring, by an image processor, a periodicity of the image data for each of the one or more pixel locations over the series of images, the periodicity corresponding to an electromechanical signal of the heart in the region corresponding to the measured one or more pixel locations;   analyzing the electromechanical signal to determine one or more patterns characteristic of the arrhythmia;   if the electromechanical signal indicates the arrhythmia is a focal arrhythmia, identifying a location of a focal zone and a subsequent propagation of cardiac activation;   if the electromechanical signal indicates the arrhythmia is a reentrant arrhythmia, performing a Fourier analysis on the electromechanical signal to determine a cycle lengths and one or more propagation patterns; and   if the electromechanical signal indicates atrial flutter, imaging the heart to identify an anatomic structure and guide ablation to treat the arrhythmia.   
     
     
         28 . The method of  claim 27 , wherein the ablation comprises radio-frequency ablation, the method further comprising measuring myocardial strains and differences between the myocardial strains before or after the radio-frequency ablation.