System and method for evaluating and optimizing the contribution of particular heart chambers to the overall efficacy of cardiac pacing therapy

Abstract

Techniques are provided for evaluating and optimizing the contribution of particular heart chambers to pacing efficacy. Briefly, a pacemaker temporarily alters the mode with which pacing therapy is delivered so as to selectively alter the heart chambers that are paced. The pacemaker detects any transient changes in pacing efficacy following the alteration in pacing mode. The pacemaker then assesses the contribution of particular heart chambers to pacing efficacy based on the alteration in the pacing mode and on any transient changes in the pacing efficacy. Additionally, techniques are provided herein for automatically adjusting pacing parameters to optimize the contribution of particular chambers to pacing efficacy.

1 . A system for use with an implantable cardiac stimulation device equipped to deliver pacing therapy to the heart of a patient in which the device is implanted, the system comprising:
 a pacing controller operative to control the delivery of pacing therapy; and   a heart chamber contribution evaluation unit operative to evaluate the contribution of a particular heart chamber to the overall efficacy of pacing therapy based on a temporary alteration in pacing mode and based on any transient changes in the efficacy of the pacing therapy following the alteration in pacing mode.   
   
   
       2 . The system of  claim 1  wherein the heart chamber contribution evaluation unit includes:
 a pacing mode temporary adjustment unit operative to temporarily alter the pacing mode with which pacing therapy is delivered, the pacing mode specifying which chambers are paced;   a pacing efficacy detector operative to detect transient changes in the efficacy of pacing therapy following the alteration in pacing mode; and   a heart chamber contribution determination unit operative to determine the contribution of the particular heart chamber to the overall efficacy of pacing therapy based on the alteration in pacing mode and based on the transient changes in the effectiveness of the pacing therapy.   
   
   
       3 . The system of  claim 1  wherein pacing therapy is controlled by the pacing controller subject to one or more pacing parameters that affect the efficacy of pacing therapy and wherein the system further includes a heart chamber contribution optimization unit operative to adjust the pacing parameters based on the contribution of the particular heart chamber to pacing efficacy. 
   
   
       4 . The system of  claim 1  further comprising a diagnostic controller operative to record diagnostic information indicative of the contribution of the particular heart chamber to the overall efficacy of pacing therapy. 
   
   
       5 . The system of  claim 1  further comprising a tracking unit operative to track changes over time in the contribution of the particular heart chamber to the overall efficacy of pacing therapy. 
   
   
       6 . The system of  claim 1  further comprising an internal warning device operative to generate warning signals if the contribution of the particular heart chamber to the overall efficacy of pacing therapy falls below a predetermined minimum acceptable amount. 
   
   
       7 . The system of  claim 2  wherein the pacing mode temporary adjustment unit is operative to temporarily alter the pacing mode by switching between a biventricular pacing mode and a monoventricular pacing mode. 
   
   
       8 . The system of  claim 2  wherein the pacing mode temporary adjustment unit is operative to temporarily alter the pacing mode by switching between a dual-chambered pacing mode, wherein pacing is performed in both the atria and ventricles, and a non-dual-chambered pacing mode, wherein pacing is exclusively performed in either the atria or the ventricles. 
   
   
       9 . The system of  claim 2  wherein the pacing mode temporary adjustment unit is operative to temporarily alter the pacing mode by switching among any of: AAI; VVI; DDD; DDI; VDD; and VOO pacing modes. 
   
   
       10 . The system of  claim 2  wherein the pacing mode temporary adjustment unit is operative to temporarily alter the pacing mode for a duration in the range of two to sixty seconds. 
   
   
       11 . The system of  claim 2  wherein the pacing efficacy detector is operative to detect signals representative of one or more of: morphological features of an intracardiac electrogram (IEGM); blood oxygen saturation; blood pressure; contractility; stroke volume; cardiac output; and a heart output pulse waveform. 
   
   
       12 . The system of  claim 11  wherein the pacing efficacy detector is operative to detect transient changes in the peak amplitude of the signals. 
   
   
       13 . The system of  claim 3  wherein the pacing parameters include one or more of: an atrioventricular (A-V) delay; an inter-ventricular (V-V) delay; and an inter-atrial (A-A) delay. 
   
   
       14 . The system of  claim 3  wherein the heart chamber contribution optimization system is operative to adjust the pacing parameters to increase the contribution of the particular heart chamber to the overall efficacy of pacing therapy. 
   
   
       15 . The system of  claim 14  wherein the heart chamber contribution optimization unit is operative to adjust the pacing parameters to maximize the contribution of the particular heart chamber. 
   
   
       16 . The system of  claim 3  wherein the heart chamber contribution optimization unit is operative to adjust the pacing parameters to decrease the contribution of the particular heart chamber to the overall efficacy of pacing therapy. 
   
   
       17 . A system for adjusting pacing parameters used in delivering cardiac pacing therapy to the heart of a patient in which an implantable cardiac stimulation device is implanted, the system comprising:
 means for temporarily altering a pacing mode with which pacing therapy is delivered, the pacing mode specifying which chambers are paced;   means for detecting any transient changes in the efficacy of pacing therapy following the temporary alteration in pacing mode; and   means for evaluating the contribution of a particular heart chamber to the overall efficacy of pacing therapy based on any transient changes in the efficacy of the pacing therapy following an alteration in pacing mode.   
   
   
       18 . The system of  claim 17  further comprising:
 means for controlling pacing therapy by using one or more pacing parameters that affect the efficacy of pacing therapy; and   means for adjusting the pacing parameters based on the contribution of the particular heart chamber to pacing efficacy.   
   
   
       19 . The system of  claim 1  further comprising means for recording diagnostic information indicative of the contribution of the particular heart chamber to the overall efficacy of pacing therapy. 
   
   
       20 . The system of  claim 1  further comprising means for generating warning signals if the contribution of the particular heart chamber to the overall efficacy of pacing therapy falls below a predetermined minimum acceptable amount.