Method and apparatus for automatic determination of hemodynamically optimal cardiac pacing parameter values

Abstract

For cardiac rhythm management a combination of cardiac pacing and a noninvasive heart monitoring is proposed for the determination of a set of programmable pacing parameters hemodynamically most beneficial to the patient. The apparatus incorporates a cardiac pacemaker ( 130 ) and a thoracic electrical bioimpedance (TEB) heart monitor ( 120 ). This combination allows the creation of a closed-loop system that conveniently and effectively obtains pacing parameter settings providing hemodynamically optimal pacing therapy to the patient as determined by measuring and recording of stroke volume (SV), cardiac output (GO), and other indices of ventricular performance by the heart monitor during an optimization cycle automatically employing different permutations of values of pacing parameters such as atrioventricular delays, inter-atrial delay, inter-ventricular delay, or heart rate, that are sequentially programmed to the pacemaker. The hemodynamically optimal permutation of pacing parameter values is determined from all recordings and programmed to the pacemaker for permanent or temporary pacing therapy.

I claim:  
     
         1 . Method of automatic determination of a multi-chamber cardiac pacemaker's programmable pacing parameter values providing hemodynamically optimal pacing therapy, comprising 
 defining one or more pacing parameters, such as atrioventricular delays, inter-atrial delay, inter-ventricular delay, or heart rate, which are subject to variation during an optimization cycle,    defining a variation range for values of each pacing parameter and a variation step width for stepping through the variation range during the optimization cycle,    with the number of pacing parameters subject to variation and the number of applicable variation steps for each parameter defining the number of permutations of pacing parameter values and, thus, the sequence of the optimization cycle,    within an optimization cycle sequentially programming the pacemaker with one permutation of pacing parameter values after the other and taking, with each permutation applied, hemodynamic measurements of the stroke volume (SV), cardiac output (CO) or ejection fraction (EF) and other indices of ventricular performance for a predefined time period, and recording each of the measurements taken,    determining the hemodynamically optimal permutation of pacing parameter values from all recordings, and    programming the pacemaker with this hemodynamically optimal permutation of pacing parameter values for pacing therapy.    
     
     
         2 . Method according to  claim 1 , characterized in that non-invasive measurements of thoracic electrical bioimpedance (or bioadmittance) are performed to determine stroke volume (SV), cardiac output (CO) or ejection fraction (EF) and other indices of ventricular performance in combination with the cardiac pacemaker.  
     
     
         3 . Method according to  claim 2 , characterized in that the non-invasive measurements of thoracic electrical bioimpedance (or bioadmittance) are performed using an array of surface electrodes, especially ECG-type electrodes, attached to a patient's right side of his neck and the left side of the lower thorax, or electrodes located on an esophagus catheter/probe.  
     
     
         4 . Method according to  claim 2 , characterized in that the non-invasive measurements of thoracic electrical bioimpedance (or bioadmittance) are performed using a first array of surface electrodes, especially EGG-type electrodes, attached to a patient's left side of his neck and the left side of the lower thorax and a second array of surface electrodes, especially EGG-type electrodes, attached to a patient's right side of his neck and the right side of the lower thorax, or electrodes located on an esophagus catheter/probe.  
     
     
         5 . Method according to any of  claims 1  to  4 , characterized in that each permutation of pacing parameter values is applied for a period of about 30 to 120 seconds.  
     
     
         6 . Apparatus for automatic determination of a multi-chamber cardiac pacemaker's pacing parameter values providing optimal pacing therapy (optimization apparatus), comprising 
 a programmable processing unit ( 110 ) for storing an operator defined set of one or more programmable pacing parameters subject to variation and operator defined parameter specific variation ranges and step widths of values for pacing parameters, such as atrioventricular delays, inter-atrial delay, inter-ventricular delay, or heart rate, thus defining the number of permutations of pacing parameter values and the sequence of the optimization cycle,    means for programming one permutation of pacing parameter values at a time to a pacemaker ( 130 ,  170 ) in accordance with the defined sequence of the optimization cycle,    a heart monitor ( 120 ) for communication with the pacemaker for taking hemodynamic measurements of the stroke volume (SV), cardiac output (GO) or ejection fraction (EF) and other indices of ventricular performance in accordance with the defined sequence of the optimization cycle,    means ( 110 ) for recording the measurements for each permutation of applied pacing parameter values,    means ( 110 ) for determining the optimal permutation of pacing parameter values from all recordings, and    means ( 110 ) for permanently programming the pacemaker with the so found optimal pacing parameter values.    
     
     
         7 . Apparatus of  claim 6 , characterized in that the cardiac pacemaker ( 130 ) is integrated in the optimization apparatus ( 100 ).  
     
     
         8 . Apparatus of  claim 6 , characterized by display means ( 140 ) for numerically or graphically displaying the results of the measurements and/or the optimal permutation of pacing parameter values.  
     
     
         9 . Any communicate with the cardiac pacemaker ( 170 ) through which the pacemaker is programmable by the processing unit ( 110 ).  
     
     
         10 . Apparatus of  claim 6 , characterized in that the pacemaker ( 170 ) is programmable in such a way that the optimization cycle is automatically performed according to a program sequence built into the pacemaker, which can be activated, especially by the processing unit ( 110 ), in such a way that the hemodynamic measurements obtained by the heart monitor ( 120 ) can be related (synchronized) to the various permutations of pacing parameters values.  
     
     
         11 . Apparatus of claims  9  or  10 , characterized in that the interface ( 150 ) is adapted to communicate with the pacemaker ( 170 ) a set of pacing parameter values through a telemetry means ( 160 ).