Pacing Methods, Systems and Computer Program Products for Using Feedback Controlled Timing

Abstract

Methods, systems and computer program products for cardiac pacing are provided. For pacing using biventricular synchronization in a patient, a first stimulation signal is applied to a first region of a heart of the patient at a first time and a second stimulation signal applied to a second region of the heart of the patient at a second time to provide biventricular synchronization stimulation of the heart. Cardiac function of the patient associated with application of the first and the second stimulation signals is sensed and a timing relationship of the first stimulation signal to the second stimulation signal is adjusted based on the sensed cardiac function. Additionally, a cardiac timing interval, such as the A-V timing interval, may be adjusted by applying stimulation to a heart of the patient utilizing a cardiac timing interval, detecting a change in cardiac function by sensing cardiac function associated with application of the stimulation using the cardiac timing interval and adjusting the cardiac timing interval directly from the detected change in cardiac function.

1 . A method of cardiac pacing in a patient, comprising: applying stimulation to a heart of the patient utilizing a cardiac timing interval;
 detecting a change in cardiac function by sensing cardiac function associated with application of the stimulation using the cardiac timing interval; and   adjusting the cardiac timing interval directly from the detected change in cardiac function, wherein the cardiac timing interval comprises an A-V timing interval, the method further comprising repeating applying stimulation to a heart of the patient utilizing the A-V timing interval, detecting a change in cardiac function by sensing cardiac function associated with application of the stimulation using the A-V timing interval and adjusting the A-V timing interval directly from the detected change in cardiac function without predicting a desired A-V timing until adjusting the A-V timing interval does not improve cardiac function,   wherein the step of detecting a change in cardiac function by sensing cardiac function comprises detecting a change in cardiac function by measuring changes in distance and/or the rate of change in distance between at least two locations on the heart of the patient and wherein the step of adjusting the A-V timing interval comprises the step of adjusting the A-V timing interval directly from the changes in distance and/or the rate of change in distance.   
     
     
         2 . The method of  claim 1 , wherein the cardiac timing interval comprises a pacing interval. 
     
     
         3 . The method of  claim 1 , wherein the step of applying stimulation comprises applying stimulation to the heart utilizing a single electrode. 
     
     
         4 . The method of  claim 1 , wherein the cardiac timing interval comprises a timing interval from a reference signal to a left ventricular stimulation and/or a timing interval from the reference signal to a right ventricular stimulation. 
     
     
         5 . The method of  claim 1 , wherein the cardiac timing interval comprises a timing interval from a reference signal to a left ventricular stimulation and a timing interval from the reference signal to a right ventricular stimulation, and the timing interval is adjusted so as to adjust a timing relationship between the left ventricular stimulation and the right ventricular stimulation. 
     
     
         6 . The method of  claim 4 , wherein the cardiac timing interval is adjusted so as to adjust a timing between both the left ventricular stimulation and the right ventricular stimulation and the reference signal. 
     
     
         7 . The method of  claim 4 , wherein the reference signal comprises a spontaneous atrial signal. 
     
     
         8 . The method of  claim 4 , wherein the reference signal comprises a pacing stimulation. 
     
     
         9 . The method of  claim 1 , wherein the step of detecting a change in cardiac function comprises detecting a change in cardiac function by sensing changes in impedance and wherein the step of adjusting the A-V timing interval comprises adjusting the A-V timing interval directly from the sensed changes in impedance. 
     
     
         10 . The method of  claim 1 , wherein the step of detecting a change in cardiac function by sensing changes in impedance comprises detecting a change in cardiac function by measuring impedance utilizing a conductance catheter positioned proximate a left ventricle of the heart of the patient. 
     
     
         11 . The method of  claim 1 , wherein the step of detecting a change in cardiac function by measuring changes in distance and/or the rate of change in distance comprises detecting a change in cardiac function by measuring changes in distance and/or the rate of change in distance between at least an electrode positioned on a left ventricle and an electrode positioned within a right ventricle of the heart of the patient. 
     
     
         12 . The method of  claim 1 , wherein the step of detecting a change in cardiac function by measuring changes in distance and/or the rate of change in distance comprises detecting a change in cardiac function by measuring changes in distance and/or the rate of change in distance utilizing ultrasonic crystals. 
     
     
         13 . The method of  claim 12 , wherein the ultrasonic crystals are placed on electrodes that receive the first and the second stimulation signals. 
     
     
         14 . The method of  claim 1 , wherein the step of detecting a change in cardiac function by sensing cardiac function comprises detecting a change in cardiac function by measuring motion of a location associated with the heart of the patient and wherein the step of adjusting the A-V timing interval comprises adjusting the A-V timing interval directly from the measured motion. 
     
     
         15 . The method of  claim 14 , wherein the location associated with the heart of the patient comprises a left ventricle of the heart of the patient. 
     
     
         16 . The method of  claim 14 , wherein the step of detecting a change in cardiac function by measuring motion comprises detecting motion utilizing an accelerometer. 
     
     
         17 . The method of  claim 16 , further comprising:
 determining a derivative of the detected motion; and   estimating cardiac function based on the determined derivative.   
     
     
         18 . The method of  claim 16 , further comprising:
 determining an integral of the detected motion; and   estimating cardiac function based on the determined integral.   
     
     
         19 .- 30 . (canceled) 
     
     
         31 . A system for cardiac pacing in a patient, comprising:
 an electrode stimulation timing circuit configured to control a cardiac timing interval of application of stimulation to a heart of the patient;   a cardiac function sensing circuit configured to detect a change in cardiac function by sensing cardiac function associated with application of the stimulation; and   a feedback control circuit operatively associated with the electrode stimulation timing circuit and the cardiac function sensing circuit and configured to adjust the cardiac timing interval directly from the detected change in cardiac function wherein the cardiac timing interval comprises an A-V timing interval, and the electrode stimulation timing circuit is configured to repeat applying stimulation to a heart of the patient utilizing the A-V timing interval, the cardiac function sensing circuit is configured to detect a change in cardiac function by sensing cardiac function associated with application of the stimulation using the A-V timing interval, and the feedback control circuit is configured to adjust the A-V timing interval directly from the detected change in cardiac function until adjusting the A-V timing interval does not improve cardiac function, wherein the cardiac function sensing circuit is further configured to detect a change in cardiac function by measuring changes in distance and/or the rate of change in distance between at least two locations on the heart of the patient, and the feedback control circuit is configured to adjust the A-V timing interval directly from the changes in distance and/or the rate of change in distance without predicting a desired A-V interval.   
     
     
         32 . A system for cardiac pacing in a patient, comprising:
 means for applying stimulation to a heart of the patient utilizing a cardiac timing interval;   means for detecting a change in cardiac function by sensing cardiac function associated with application of the stimulation using the cardiac timing interval; and   means for adjusting the cardiac timing interval directly from the detected change in cardiac function, wherein the cardiac timing interval comprises an A-V timing interval, and the system further comprises:   means for repeating applying stimulation to a heart of the patient utilizing an A-V timing interval;   means for detecting a change in cardiac function by sensing cardiac function associated with application of the stimulation using the A-V timing interval by measuring changes in distance and/or the rate of change in distance between at least two locations on the heart of the patient; and   means for adjusting the A-V timing interval directly from the detected change in cardiac function from the changes in distance and/or the rate of change in distance without predicting a desired A-V timing until adjusting the A-V timing interval does not improve cardiac function.