Devices and methods for accelerometer-based characterization of cardiac synchrony and dyssynchrony

Abstract

Systems and methods according to the invention employ an acceleration sensor to characterize the synchrony or dyssynchrony of the left ventricle. Patterns of acceleration related to myocardial contraction can be used to assess synchrony or dyssynchrony. Time-frequency transforms and coherence are derived from the acceleration. Information and numerical indices determined from the acceleration time frequency transforms and coherence can be used to find the optimal pacing location for cardiac resynchronization therapy. Similarly, the information can be used to optimize timing intervals including V to V and A to V timing.

1 . A device for measuring cardiac dyssynchrony, comprising: 
 a. a catheter having a tubular polymeric outer lumen configured for accessing the coronary sinus, the lumen having a proximal end and a distal end, such that when installed in a patient the distal end resides in the coronary sinus;    b. a second tubular polymeric lumen for receiving a guide wire;    c. an acceleration sensor disposed at the distal end of the outer lumen; and    d. at least one decoupling capacitor adjacent to said acceleration sensor.    
     
     
         2 . A device of  claim 1 , further comprising a guide wire, wherein said guide wire has an electrically conductive tip.  
     
     
         3 . A device of  claim 1  wherein said configuration includes a curve of 90 degrees or greater.  
     
     
         4 . A device of  claim 1  wherein said sensor is surface mounted in the distal catheter region to a circuit board.  
     
     
         5 . A device of  claim 1  wherein said decoupling capacitor is surface mounted in the distal catheter region to a circuit board.  
     
     
         6 . A device of  claim 1  wherein said sensor measures 3 different axes of acceleration.  
     
     
         7 . A device of  claim 1 , wherein said sensor is a capacitive type sensor.  
     
     
         8 . A device of  claim 1 , further comprising a microprocessor.  
     
     
         9 . A device of  claim 1 , wherein said microprocessor is programmed to compute dyssynchrony indices from acceleration signals.  
     
     
         10 . A device of  claim 1  wherein said device measures global dyssynchrony of the left ventricle.  
     
     
         11 . A system for measuring dyssynchrony, comprising: 
 a. a catheter with an acceleration sensor mounted in the distal region of the catheter;    b. a pacing device;    c. a microprocessor, said microprocessor programmed to convert acceleration patterns into one or more dyssynchrony indices; and    d. a display for showing acceleration patterns or dyssynchrony indices.    
     
     
         12 . A system of  claim 11 , wherein said catheter is configured such that the catheter can access the coronary sinus.  
     
     
         13 . A system of  claim 11 , wherein said acceleration sensor measures acceleration in 3 axes.  
     
     
         14 . A system of  claim 11 , wherein said catheter further comprises a lumen for receiving a guide wire.  
     
     
         15 . A system as described in  claim 11 , wherein said pacing device is a pacing guide wire.  
     
     
         16 . A system as described in  claim 11 , wherein the microprocessor is programmed to produce a phase average of acceleration and ECG signals.  
     
     
         17 . A system as described in  claim 11 , wherein the microprocessor is programmed to identify the peak acceleration and a QRS component of the ECG of the phased averaged signals.  
     
     
         18 . A system as described in  claim 11 , wherein the microprocessor is programmed to perform Fourier transformation of acceleration signals.  
     
     
         19 . A system of  claim 11  wherein said dyssynchrony indices include one or more of the following: 
 Time delay from onset of ventricular electrical activity to onset of LV motion during systole;    Time delay from onset of ventricular electrical activity to peak LV motion during systole;    Time delay from onset of ventricular electrical activity to onset of LV motion during diastole;    Time delay from onset of ventricular electrical activity to peak LV motion during diastole;    The ratio of the peak motion during systole and diastole;    The time interval between the peak motion of systole and diastole;    Number of motion peaks during systole greater than a threshold;    Time delay between two highest peaks of motion during systole;    Variability of time delay from onset of ventricular electrical activity to peak motion in each acceleration axis (X, Y, or Z);    Variability of peak motion in each independent axis (X, Y, or Z);    Reduction in the peak acceleration of delayed motion;    Frequency of peak amplitude of power spectrum;    The acceleration axis with the dominant frequency in power spectrum Cross correlations of time-frequency transforms between ECG signal and acceleration signals or between different acceleration signal axes.    
     
     
         20 . A method for measuring cardiac dyssynchrony, comprising: 
 a. placing one 3-axis acceleration sensor for disposition within a patient's coronary sinus;    b. wherein said sensor measures the global acceleration of the left ventricle;    c. and wherein said measured acceleration forms a pattern indicative of global dyssynchrony of the left ventricle.    
     
     
         21 . A method of  claim 20 , further comprising: 
 a. converting said acceleration pattern into a numerical or dyssynchrony index;    b. wherein said numerical or dyssynchrony indices may include one or more of the following: 
 Time delay from onset of ventricular electrical activity to onset of LV motion during systole;  
 Time delay from onset of ventricular electrical activity to peak LV motion during systole;  
 Time delay from onset of ventricular electrical activity to onset of LV motion during diastole;  
 Time delay from onset of ventricular electrical activity to peak LV motion during diastole;  
 The ratio of the peak motion during systole and diastole;  
 The time interval between the peak motion of systole and diastole;  
 Number of motion peaks during systole greater than a threshold;  
 Time delay between two highest peaks of motion during systole;  
 Variability of time delay from onset of ventricular electrical activity to peak motion in each acceleration axis (X, Y, or Z);  
 Variability of peak motion in each independent axis (X, Y, or Z);  
 Reduction in the peak acceleration of delayed motion;  
 Frequency of peak amplitude of power spectrum;  
 The acceleration axis with the dominant frequency in power spectrum Cross correlations of time-frequency transforms between ECG signal and acceleration signals or between different acceleration signal axes.  
   
     
     
         22 . A computer-readable medium, containing instructions for causing a computer to carry out the method of  claim 21 .  
     
     
         23 . A method for identifying an optimal pacing location, comprising: 
 a. introducing an acceleration-measuring catheter into the coronary sinus of a patient;    b. measuring a baseline pattern of left ventricular myocardial acceleration;    c. placing a right ventricular pacing device in the right ventricle;    d. placing a left ventricular pacing device in or on the left ventricle;    e. moving the left ventricular pacing device to a plurality of locations in or on the left ventricle;    f. performing biventricular or left ventricular pacing at the plurality of locations with the left ventricular pacing device;    g. measuring the acceleration pattern with biventricular or left ventricular pacing;    h. determining a location of the left ventricle with a less dyssynchronous acceleration pattern; and    i. selecting the less dyssynchronous location to implant a CRT pacing lead.    
     
     
         24 . The method of  claim 23  further comprising converting said acceleration pattern into one or more dyssynchrony indices.  
     
     
         25 . A computer-readable medium, containing instructions for causing a computer to carry out the method of  claim 24 .  
     
     
         26 . A method of  claim 23  further comprising moving said right ventricular pacing device to a plurality of locations in the right ventricle and measuring dyssynchrony at the plurality of locations.  
     
     
         27 . A method of  claim 26  further comprising implanting a right ventricular pacing lead in a location with a less dyssynchronous acceleration pattern or numerical index.  
     
     
         28 . A method for optimizing the V to V and A to V timing intervals, comprising: 
 a. introducing an acceleration-measuring catheter into the coronary sinus of a patient;    b. measuring a baseline pattern of left ventricular myocardial acceleration;    c. placing a right ventricular pacing device in the right ventricle;    d. placing a left ventricular pacing device in or on the left ventricle;    e. moving the left ventricular pacing to a plurality of locations in or on the left ventricle;    f. performing biventricular pacing at the plurality of locations of the left ventricular pacing catheter;    g. measuring the acceleration pattern with biventricular pacing;    h. determining the location of pacing in or on the left ventricle with a less dyssynchronous acceleration pattern;    i. selecting the less dyssynchronous location to implant a CRT pacing lead;    j. varying the V to V timing intervals between a range of millisecond delays and selecting the timing that produces a less dyssynchronous acceleration pattern.    
     
     
         29 . A method of  claim 28  further comprising using the acceleration pattern to determine one or more dyssynchrony indices.  
     
     
         30 . A method of  claim 28 , further comprising varying the A to V timing interval within a range and selecting the timing that produces a less dyssynchronous acceleration pattern.  
     
     
         31 . A method for improving the outcome of CRT, comprising: 
 a. placing a catheter with an acceleration sensor in the coronary sinus;    b. diagnosing the presence of dyssynchrony by measuring an acceleration pattern that characterizes dyssynchrony;    c. inserting a pacing guide wire;    d. test pacing with said pacing guide wire a plurality of locations in or on the left ventricle;    e. identifying locations with a less dyssynchronous acceleration pattern than that found in step b; and    f. implanting a left ventricular lead in said identified location.    
     
     
         32 . The method of  claim 31 , wherein the acceleration sensor includes three acceleration axes.  
     
     
         33 . The method of  claim 30 , further comprising using said acceleration pattern to derive one or more dyssynchrony indices.  
     
     
         34 . A method of  claim 32  further comprising deriving dyssynchrony indices from said acceleration patterns.  
     
     
         35 . A computer-readable medium, containing instructions for causing a computer to carry out the method of  claim 34 .  
     
     
         36 . A method for measuring cardiac dyssynchrony, comprising: 
 g. placing a 3-axis acceleration sensor for disposition within a patient's coronary sinus;    h. measuring the global acceleration of the left ventricle with the sensor;    i. creating a time-frequency transform; and    j. using frequency or frequency energy data from said time-frequency transform to characterize dyssynchrony.    
     
     
         37 . A method for measuring cardiac dyssynchrony, comprising: 
 k. placing a 3-axis acceleration sensor for disposition within a patient's coronary sinus    l. measuring the global acceleration of the left ventricle with the sensor;    m. using the acceleration data to create a measure of coherence; and    n. characterizing dyssynchony using the coherence.