PMT detecting pacemaker
First Claim
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1. A heart pacemaker comprising:
- sensing means for detecting atrial events in a heart beating in successive heart cycles;
stimulating means for stimulating the ventricle of said heart, said atrial events and the stimulation of the ventricle constituting cardiac events;
variable delay means for generating a variable time delay between the detection of an atrial event and the stimulation of the ventricle;
time measuring means for measuring a time interval between consecutive cardiac events, at least one of said detected events being a natural heartbeat detected by said sensing means;
calculating means for calculating the correlation between said time delay and said time interval measured by said time measuring means; and
logic means for indicating the presence of a pacemaker-mediated tachycarida if the value of said correlation deviates from a predetermined value.
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Abstract
A pacemaker-mediated tachycardia (PMT) is detected by calculating the correlations for typically two to six heart cycles between, for example, spontaneous atrial beats (PP-intervals) and the pacemaker generated AV delays, which are varied in a predictable manner. The correlation is low when no PMT is present because the possible variation in the interval between spontaneous atrial beats is independent of the variation of the AV delay. Correlation is high when a PMT is present, because the interval between spontaneous atrial beats will then equal the PMT cycle time, i.e., the AV delay plus the retrograde conduction time in the heart tissue.
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Citations
10 Claims
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1. A heart pacemaker comprising:
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sensing means for detecting atrial events in a heart beating in successive heart cycles; stimulating means for stimulating the ventricle of said heart, said atrial events and the stimulation of the ventricle constituting cardiac events; variable delay means for generating a variable time delay between the detection of an atrial event and the stimulation of the ventricle; time measuring means for measuring a time interval between consecutive cardiac events, at least one of said detected events being a natural heartbeat detected by said sensing means; calculating means for calculating the correlation between said time delay and said time interval measured by said time measuring means; and logic means for indicating the presence of a pacemaker-mediated tachycarida if the value of said correlation deviates from a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification