Diagnostic function data storage and telemetry out for rate responsive cardiac pacemaker

An implantable, rate responsive cardiac pacemaker comprising:

• means for determining an occurrence of selected cardiac events;
• means for detecting and processing a physiologic parameter;
• means for delivering pacing pulses at a selected pacing rate;
• means for varying the pacing rate as a function of a stored algorithm having at least one programmed-in rate responsive modifier value for setting the pacing rate in dependence upon the measured physiologic parameter and the occurrence of selected cardiac events;
• means for establishing at least one rate response algorithm modifier value;
• means for periodically optimizing the rate response algorithm modifier value to achieve a predetermined rate achievement criteria;
• means for transmitting signals representative of the optimized rate responsive modifier value and the programmed-in rate responsive modifier value to a remote location external of said implantable pacemaker;
• means for storing n periodic changes of the first rate response algorithm modifier value and a time of change of the response algorithm modifier value in n memory locations;
• means for transmitting the n periodic changes to said remote location and their corresponding times;
• means for selectively disabling said means for varying the pacing rate, and for operating said pacemaker at a further defined fixed or varying pacing rate;
• means for deriving a projected pacing rate as a function of said stored algorithm and storing projected rate trend data in memory over a predetermined time duration, said rate trend data indicative of a trend in said pacing rate;
• and
• means for transmitting the projected rate trend data in conjunction with the algorithm modifier value to said remote location.

An implantable, rate responsive cardiac pacemaker comprising:

• means for determining an occurrence of selected cardiac events;
• means for detecting and processing a physiologic parameter;
• means for delivering pacing pulses at a selected pacing rate;
• means for varying the pacing rate as a function of a stored algorithm having at least one programmed-in algorithm modifiers rate responsive modifier value for setting the pacing rate in dependence upon the measured physiologic parameter and the occurrence of selected cardiac events;
• modifier value establishing means for establishing at least one rate response algorithm modifier value;
• means for periodically optimizing the rate response algorithm modifier value to achieve a predetermined rate achievement criteria;
• and,
• means for transmitting signals representative of the optimized rate responsive modifier value and the programmed-in rate responsive modifier value to a remote location external of said implantable pacemaker;
• wherein said means for detecting and processing a physiologic parameter further comprises:
• first sensor and signal processing means for deriving a first physiologic signal representative of a cardiac function;
• and
• second sensor and signal processing means for deriving a second physiologic signal representative of a metabolic demand for cardiac output;
• and wherein said means for varying the pacing rate further comprises means for selectively employing either or both of the first and second physiologic signals to derive a pacing rate;
• and wherein said modifier value establishing means further comprises means for establishing first and second gain control values and a relative weighting coefficient for said first and second physiologic signals;
• and further comprising:
• means for deriving a pacing rate as a function of the first and/or second physiologic signals modified by said gain control values and weighting coefficient;
• and wherein said optimizing means periodically optimizes the gain control values and weighting coefficient.

An implantable, programmable cardiac pacemaker comprising:

• means for determining an occurrence of selected cardiac paced and sensed events;
• means for delivering pacing pulses at a predetermined pacing rate corresponding to an interval elapsed from a preceding paced or sensed event;
• means for measuring a predetermined parameter associated with each one of said selected cardiac events;
• means for registering occurrences of said selected cardiac events;
• means for classifying each said registered event into respective classes of said parameter associated with said event in accordance with a measured value of said parameter;
• means for accumulating counts of said registered events for each said class thereby providing data of a distribution of said registered events;
• means for halting accumulating of said counts of said registered events upon achievement of a predetermined count of said registered events for at least one of said classes and registering a time corresponding to the achievement of the maximum count in association with the specific register;
• and
• means for outputting signals representative of said accumulated counts and said time to a location external of said implantable pacemaker.

A method for providing an optimized pacing rate of stimulation pulses in a rate responsive cardiac pacemaker, as a function of at least one selected rate control parameter, each of said rate control parameters having a value which varies as a function of changes in a patient's physiologic demand for cardiac output, the method comprising the steps of:

• sensing each of said rate control parameter values and for providing a sensor output representative thereof;
• deriving desired pacing rates for each of said sensor means as a function of said sensor output signals corresponding thereto, modified by a predetermined rate response algorithm modifier function for each of said sensor means, such that for a predetermined change in sensor output signal a corresponding change in said desired pacing rate is provided;
• periodically monitoring a relationship between each of said derived desired pacing rates and a defined achievement criterion corresponding thereto over a predetermined optimization period, for providing an achievement output indicative of each of said monitored relationships, wherein each of said achievement criterion is reflective of expected levels of exercise of said patient during said optimization period;
• providing optimized pacing rates as a function of each of said derived desired pacing rates;
• adjusting each of said rate response algorithm modifier functions as a function of said achievement output corresponding thereto, such that each of said adjusted rate response functions provides an increased or decreased change in desired pacing rate corresponding to said predetermined change in sensor output;
• storing in memory, said rate response algorithm modifier functions adjusted during the optimization periods;
• and upon receipt of an interrogation command, transmitting the stored functions to a remote location.