Dual chamber pacemaker with AV extension and PMT control
First Claim
1. A dual chamber pacemaker having ventricular generating means for generating ventricular pace pulses, atrial sensing means for sensing atrial events, AV means for timing out an AV interval following an atrial event and triggering generation of a ventricular pace pulse following said AV time out, and VV means for timing out a ventricular pacing interval and for triggering generating of a ventricular pace pulse following said V--V time out in the absence of an earlier ventricular event, further comprising VA test means for carrying out a VA interval test, said test means comprisingchanging means for changing at least one of said AV and VV intervals to a predetermined interval for a predetermined number of pacemaker cycles;
- interval means for determining a measure of each VA interval over a predetermined number of cycles;
equality means for determining VA interval equality from said VA interval measures;
comparing means for comparing a measure of the equal VA interval when equality is determined with both predetermined respective retrograde conduction (RC) and far field R wave sensing (FFRS) criteria;
FFRS means for decreasing the opportunity of said atrial sensing means to sense far field R waves when said FFRS criterion is met; and
RC means for disabling response by said pacemaker to a retrogrde conduction when said RC criterion is met.
1 Assignment
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Accused Products
Abstract
A dual chamber pacemaker is provided having incorporated therein a VA conduction test for concurrently testing for the conditions of retrograde conduction (RC) and far field R wave sensing (FFRS). The pacemaker changes the AV or VV interval to a predetermined interval over a number of pacemaker cycles, and determines whether the VA interval remains substantially unchanged, i.e., the VA intervals are substantially equal. When VA interval equality is determined, the pacemaker checks the measure of VA interval with stored RC and FFRS criteria to determine whether either can be verified. Respective corrective steps are taken if either RC or FFRS is verified.
47 Citations
34 Claims
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1. A dual chamber pacemaker having ventricular generating means for generating ventricular pace pulses, atrial sensing means for sensing atrial events, AV means for timing out an AV interval following an atrial event and triggering generation of a ventricular pace pulse following said AV time out, and VV means for timing out a ventricular pacing interval and for triggering generating of a ventricular pace pulse following said V--V time out in the absence of an earlier ventricular event, further comprising VA test means for carrying out a VA interval test, said test means comprising
changing means for changing at least one of said AV and VV intervals to a predetermined interval for a predetermined number of pacemaker cycles; -
interval means for determining a measure of each VA interval over a predetermined number of cycles; equality means for determining VA interval equality from said VA interval measures; comparing means for comparing a measure of the equal VA interval when equality is determined with both predetermined respective retrograde conduction (RC) and far field R wave sensing (FFRS) criteria; FFRS means for decreasing the opportunity of said atrial sensing means to sense far field R waves when said FFRS criterion is met; and RC means for disabling response by said pacemaker to a retrogrde conduction when said RC criterion is met. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. The dual chamber pacemaker having ventricular generating means for generating ventricular pace pulses and atrial sensing means for sensing atrial events, characterized by
change means for changing the timing relationship between atrial senses and following ventricular pulses; -
VA means for determining a measure of VA time intervals following ventricular pulses of changed timing relationship; equality means for determining if said VA following time remains within a predetermined deviation and thus substantially constant; and response means for changing pacemaker operation in response to a substantially constant determination. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. The dual chamber pacemaker having ventricular generating means for generating ventricular stimulus pulses and atrial sensing means for sensing atrial events, characterized by
change means for changing the timing relationship between sensed atrial events and following ventricular pulses; -
VA means for determining the VA time following ventricular pulses of changed timing relationship; determining means for determining if said following time remains within a predetermined deviation and thus substantially constant; determining means for determining when said VA time is below a predetermined upper limit and when it is below a predetermined lower limit; and response means for controlling the response of said pacemaker with a first response when said VA time is below said lower limit and with a second response when said VA time is above said lower limit and below said upper limit. - View Dependent Claims (26, 27)
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- 28. A dual chamber pacemaker having ventricular generating means for generating ventricular stimulus pulses and atrial sensing means for sensing atrial events, characterized by far field R wave sensing (FFRS) control means for detecting an FFRS condition and for changing pacemaker operation in response thereto, said control means comprising atrial rate means for determining the rate of atrial senses per cycle over a predetermined interval and for identifying an FFRS condition when said rate exceeds a predetermined number r, wherein r is greater than 1 and less than 2.
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30. A method carried out by a dual chamber pacemaker, said pacemaker having ventricular generating means for generating ventricular pace pulses and atrial sensing means for sensing atrial events, said method comprising
initiating a search to determine by said search when one of either far field R wave sensing (FFRS) or retrograde conduction (RC) conditions exist, when one of said conditions is determined to exist, determining which one exists, and changing the operation of said pacemaker as a function of whether FFRS or RC is determined to exist.
Specification