Apparatus and methods of optimizing atrioventricular pacing delay intervals

Abstract

Provided herewith are methods and apparatus for optimizing an atrioventricular (AV) pacing delay interval based upon ECG-based optimization is calculated as a linear function of P-wave duration, sensed PR (intrinsic) interval, sensed or paced QRS duration and heart rate. Since the relationship among these parameters is linear, once the coefficients are solved (which can be any value, including null) with reference to a known optimized AV interval (AVopt) such as from an echocardiographic study, an AVopt value can be dynamically adjusted in an ambulatory subject. The various combinations of values can be loaded into a look up table or calculated automatically. And, since some of the parameters do not typically change much over time they can be determined acutely and fed into the equation while the other values can be measured frequently. The parameter values can be measured by an implantable medical device such as a dual- or triple-chamber pacemaker.

1 . A method of adjusting an operating atrio-ventricular (AV) interval in a pacing therapy delivery device, wherein the operating atrio-ventricular interval extends between delivery of an atrial pacing pulse and delivery of a following ventricular pacing pulse, comprising:
 defining a minimum duration as a predetermined certain value;   monitoring occurrences of P-waves;   determining a time of an end of a given P-wave end relative to time of onset of the given P-wave;   subsequently delivering an atrial pacing pulse following the given P-wave to trigger a subsequent P-wave;   employing the determined time to modify the operating atrio-ventricular interval extending between the subsequently delivered atrial pacing pulse and delivery of a following subsequent ventricular pacing pulse to provide an interval between the end of the subsequent P-wave and the beginning of a QRS complex triggered by the subsequent following ventricular pacing pulse above the predetermined certain value; and   delivering the subsequent ventricular pacing pulse on expiration of the modified operating atrio-ventricular interval.   
     
     
         2 . The method of  claim 1  wherein the time of onset of the given P-wave comprises time of delivery of an atrial pacing pulse triggering the given P-wave. 
     
     
         3 . The method of  claim 1  wherein determining the time of the end of the given P-wave comprises measuring one of a slope of the given P-wave, a threshold crossing of the given P-wave, and a change in a polarity of the cardiac signal. 
     
     
         4 . The method of  claim 1  further comprising operating the pacing delivery device in a bi-ventricular pacing mode at the operating atrio-ventricular interval. 
     
     
         5 . The method of  claim 1  further comprising:
 measuring a heart rate; and 
 adjusting the operating atrio-ventricular interval in response to a change in the monitored heart rate. 
 
     
     
         6 . A method of adjusting an operating atrio-ventricular (AV) interval in a pacing therapy delivery device, wherein the operating atrio-ventricular interval extends between detection of a P-wave and delivery of a following ventricular pacing pulse, comprising:
 defining a minimum duration as a predetermined certain value;   monitoring occurrences of P-waves;   determining a time of an end of a given P-wave end relative to time of detection of the given P-wave;   detecting a subsequent P-wave following the given P-wave;   employing the determined time to modify the operating atrio-ventricular interval extending between detection of the subsequent P-wave and delivery of a following subsequent ventricular pacing pulse to provide an interval between the end of the subsequent P-wave and the beginning of a QRS complex triggered by the subsequent ventricular pacing pulse above the predetermined certain value; and   delivering the subsequent ventricular pacing pulse on expiration of the modified operating atrio-ventricular interval.   
     
     
         7 . The method of  claim 6  wherein the time of detection of the given P-wave comprises time of onset of the given P-wave. 
     
     
         8 . The method of  claim 6  wherein determining the time of the end of the given P-wave comprises measuring one of a slope of the given P-wave, a threshold crossing of the given P-wave, and a change in a polarity of the cardiac signal. 
     
     
         9 . The method of  claim 6  further comprising operating the pacing delivery device in a bi-ventricular pacing mode at the operating atrio-ventricular interval. 
     
     
         10 . The method of  claim 6  further comprising:
 measuring a heart rate; and 
 adjusting the operating atrio-ventricular interval in response to a change in the monitored heart rate. 
 
     
     
         11 . A pacing therapy delivery device, employing an operating atrio-ventricular interval extending between delivery of an atrial pacing pulse and delivery of a following ventricular pacing pulse, comprising:
 means for defining a minimum duration as a predetermined certain value;   means for monitoring occurrences of P-waves;   means for determining a time of an end of a given P-wave end relative to onset of the given P-wave;   means for subsequently delivering an atrial pacing pulse following the given P-wave to trigger a subsequent P-wave;   means for employing the determined time to modify the operating atrio-ventricular interval extending between the subsequently delivered atrial pacing pulse and delivery of a following subsequent ventricular pacing pulse to provide an interval between the end of the subsequent P-wave and the beginning of a QRS complex triggered by the subsequent following ventricular pacing pulse above the predetermined certain value; and   means for delivering the subsequent ventricular pacing pulse on expiration of the modified operating atrio-ventricular interval.   
     
     
         12 . The device of  claim 11  wherein the time of onset of the given P-wave comprises time of delivery of an atrial pacing pulse triggering the given P-wave. 
     
     
         13 . The device of  claim 11  wherein determining the time of the end of the given P-wave comprises measuring one of a slope of the given P-wave, a threshold crossing of the given P-wave, and a change in a polarity of the cardiac signal. 
     
     
         14 . The device of  claim 11  further comprising means for operating the pacing delivery device in a bi-ventricular pacing mode at the operating atrio-ventricular interval. 
     
     
         15 . The device of  claim 11  further comprising:
 means for measuring a heart rate; and 
 means for adjusting the operating atrio-ventricular interval in response to a change in the monitored heart rate. 
 
     
     
         16 . A pacing therapy delivery device employing an operating atrio-ventricular interval extending between detection of a P-wave and delivery of a following ventricular pacing pulse, comprising:
 means for defining a minimum duration as a predetermined certain value;   means for monitoring occurrences of P-waves;   determining a time of an end of a given P-wave end relative to detection of the given P-wave;   means for detecting a subsequent P-wave following the given P-wave;   means for employing the determined time to modify the operating atrio-ventricular interval extending between detection of the subsequent P-wave and delivery of a following subsequent ventricular pacing pulse to provide an interval between the end of the subsequent P-wave and the beginning of a QRS complex triggered by the subsequent ventricular pacing pulse above the predetermined certain value; and   means for delivering the subsequent ventricular pacing pulse on expiration of the modified operating atrio-ventricular interval.   
     
     
         17 . The device of  claim 16  wherein the time of detection of the given P-wave comprises time of onset of the given P-wave. 
     
     
         18 . The device of  claim 16  wherein determining the time of the end of the given P-wave comprises measuring one of a slope of the given P-wave, a threshold crossing of the given P-wave, and a change in a polarity of the cardiac signal. 
     
     
         19 . The device of  claim 16  further comprising means for operating the pacing delivery device in a bi-ventricular pacing mode at the operating atrio-ventricular interval. 
     
     
         20 . The device of  claim 16  further comprising:
 means for measuring a heart rate; and 
 means for adjusting the operating atrio-ventricular interval in response to a change in the monitored heart rate.