Cardiac pacemaker with table-based pacing mode implementation
First Claim
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1. A cardiac pacemaker, comprising:
- sensing circuitry for sensing an electrogram signal from an electrode adapted for disposition at a cardiac location generating a sensed event when the electrogram signal exceeds a specified threshold;
pacing circuitry for delivering a pacing pulse to a pacing electrode adapted for disposition at a cardiac location;
a brady RAM containing a brady table which maps particular device states defined by timer states and/or sensed events to associated device actions which include pacing pulse delivery and/or changes in timer states;
wherein the brady table is made up of condition words representing particular device states and corresponding action words representing particular device actions;
one or more timers, state registers, and sensing comparators whose outputs define a current status word that represents the current operating state of the device; and
,a brady RAM controller configured to sequentially assert addresses of the condition words and corresponding action words in the brady table on an address bus to cause the data bits of an addressed condition word and the corresponding action word to be output from the brady RAM;
a multi-bit comparator for comparing the data bits of each sequentially addressed condition word with the current status word; and
a multi-bit buffer that, when enabled by an output from the multi-bit comparator when a condition word is found that matches the current status word, passes the data bits of the corresponding action word to a set of action inputs to cause actions specified by the action word.
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Abstract
A device and method for implementing a bradycardia pacing mode are disclosed which is mostly hardware-based but still allows the flexibility for making major changes in brady behavior normally found only in firmware-based implementations. The brady behavior of the device is encapsulated by a table in an area of RAM referred to as brady RAM, and the brady behavior can be changed by re-loading the brady RAM with a different table.
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8 Claims
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1. A cardiac pacemaker, comprising:
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sensing circuitry for sensing an electrogram signal from an electrode adapted for disposition at a cardiac location generating a sensed event when the electrogram signal exceeds a specified threshold; pacing circuitry for delivering a pacing pulse to a pacing electrode adapted for disposition at a cardiac location; a brady RAM containing a brady table which maps particular device states defined by timer states and/or sensed events to associated device actions which include pacing pulse delivery and/or changes in timer states; wherein the brady table is made up of condition words representing particular device states and corresponding action words representing particular device actions; one or more timers, state registers, and sensing comparators whose outputs define a current status word that represents the current operating state of the device; and
,a brady RAM controller configured to sequentially assert addresses of the condition words and corresponding action words in the brady table on an address bus to cause the data bits of an addressed condition word and the corresponding action word to be output from the brady RAM; a multi-bit comparator for comparing the data bits of each sequentially addressed condition word with the current status word; and a multi-bit buffer that, when enabled by an output from the multi-bit comparator when a condition word is found that matches the current status word, passes the data bits of the corresponding action word to a set of action inputs to cause actions specified by the action word. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification