Dual chamber pacemaker with automatically optimized AV delay
First Claim
1. A dual chamber pacing system having AS means for sensing atrial beats (AS), AP means for generating and delivering atrial pace pulses (AP), VS means for sensing ventricular beats (VS), VP means for generating and delivering ventricular pace pulses (VP), and AV means for timing an AV interval following an atrial event (AS or AP) and for controlling delivery of a VP at an interval according to the function AV=f(rate) following a said atrial event and in the absence of a VS, comprisingdetermining means for automatically determining an optimized AV interval corresponding to at least one predetermined pacing rate, andadjusting means for adjusting said function AV=f(rate) to comprise said determined optimized AV interval at said predetermined pacing rate.
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Abstract
The dual chamber system and method of operation contains an automatic test for determining an optimum AV interval at a test frequency such as LRL. In a preferred embodiment the test is carried out at nighttime, wherein the implanted pacer is set to asynchronous operation at LRL, and AV interval is sequenced through a range from a predetermined AVmin to a predetermined AVmax. The QT interval corresponding to each respective AV interval is determined and stored; the QT data is analyzed to determine the maximum QT interval; and the optimum AV is determined at that which corresponds to the maximum QT. The optimum AV interval thus found is incorporated into the pacer memory for use in timing out AV interval. The optimum AV data may be utilized for determining AV=fs (rate) for calculating AV interval following each AS, as well as AV=fp (rate) for calculating AV interval following an atrial pace. Alternately, a test can be performed to determine whether an incremental adjustment of AV delay is indicated. In accordance with the invention, a DDDR pacer with automatic AV delay control can be achieved, without need for an extra sensor.
175 Citations
26 Claims
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1. A dual chamber pacing system having AS means for sensing atrial beats (AS), AP means for generating and delivering atrial pace pulses (AP), VS means for sensing ventricular beats (VS), VP means for generating and delivering ventricular pace pulses (VP), and AV means for timing an AV interval following an atrial event (AS or AP) and for controlling delivery of a VP at an interval according to the function AV=f(rate) following a said atrial event and in the absence of a VS, comprising
determining means for automatically determining an optimized AV interval corresponding to at least one predetermined pacing rate, and adjusting means for adjusting said function AV=f(rate) to comprise said determined optimized AV interval at said predetermined pacing rate.
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13. A method of dual chamber operation by a pacing system implanted in a patient, said pacing system having atrial sense means for sensing natural atrial events (AS) and atrial pace means for delivering atrial pace pulses (AP), ventricular pace means for delivering ventricular pace pulses (VP), synchronizing means for controlling delivery of a said VP at an AV interval following either an AS or AP according to a function AV=f(rate), said method of operation further comprising determining an optimum AV interval at at least one rate, and adjusting said function in accordance with said optimum AV interval, said determining step comprising:
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switching said implanted pacing system into a mode wherein AP and VP pulses are delivered to the patient at a predetermined rate, each VP following a prior AP by an AV interval, testing the AV interval by adjusting the AV interval to a plurality of adjusted intervals, and determining a measure of the patient QT interval corresponding to each respective adjusted AV interval, and determining from said measures of QT intervals whether the AV interval at said predetermined rate should be changed, and changing the value of the AV interval corresponding to said predetermined rate in accordance with said testing. - View Dependent Claims (14)
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15. A dual chamber pacemaker having means for sensing atrial heartbeats (AS) and for generating ventricular pace pulses (VP) each synchronized to a preceding AS, comprising means for determining the QT intervals following a series of delivered VPs, means for analyzing said QT intervals, and AV means for setting the AV interval between an AS and a following VP, said AV means having adjusting means for adjusting said AV interval as a function of said analyzed QT intervals.
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16. A rate responsive dual chamber pacemaker having means for sensing atrial heartbeats (AS), means for generating atrial pace pulses (AP) at a rate variable through a rate range, means for generating ventricular pace pulses (VP) at a rate variable through said rate range, means for synchronizing a VP to a preceding AS, AV means for setting the AV interval between an AS or AP and a following VP, and variable means for sensing the value of a predetermined variable representative of patient cardiac hemodynamics, characterized by
determining means for determining the variation of said predetermined variable with variation of AV interval, and said AV means having adjusting means for adjusting said AV interval in accordance with said determined variation.
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24. A dual chamber pacemaker having means for sensing atrial heartbeats (AS), means for generating atrial pace pulses (AP), means for generating ventricular pace pulses (VP), lead means for delivering said pace pulses and sensing ventricular heartbeats (VS), means for synchronizing a VP to a preceding AS, AV means for setting the AV interval between an AS or AP and a following VP, variable means for sensing the value of a predetermined variable representative of patient cardiac hemodynamics, rate control means for controlling the rate of said ventricular pace pulses as a function of said variable, and characterized by
change means for changing said AV interval in a predetermined manner, determining means for determining the change in said variable attributable to said AV interval change, and said AV means having adjust means for adjusting the AV interval in accordance with said attributable variable change.
Specification