Methods and apparatus for controlling a pacing system in the presence of EMI
First Claim
1. A method of operating a pacing system to respond to a presence of electromagnetic interference tending to corrupt the features of an electrogram, comprising:
- accumulating data from sense events and delivered pacing pulses over a predetermined time interval, deriving a mean heart rate from the accumulated data, and deriving a pacing dependency percentage representing the ratio of delivered pacing pulses to the sum of delivered pacing pulses and sensed events over the predetermined time interval;
declaring an interference state if electromagnetic interference tending to corrupt the features of the electrogram is detected;
determining whether the patient is pacemaker dependent or pacemaker independent from the pacing dependency percentage;
during the declared interference state;
setting a pacing mode of the pacing system to an inhibited pacing mode if the patient is determined to be pacemaker independent, whereby pacing pulses are not delivered to the heart chamber;
setting the pacing mode to a fixed rate pacing mode if the patient is determined to be pacemaker dependent, whereby a pacing escape interval is not restarted by a sense event and pacing pulses are delivered to the heart chamber at a fixed rate; and
adjusting the pacing escape interval to provide an interference state pacing rate exceeding the mean heart rate by a predetermined increment; and
operating the pacing system in the interference state pacing mode at the interference state pacing rate, whereby the patient'"'"'s heart is paced while minimizing occurrences of parasystole.
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Accused Products
Abstract
Pacing systems are disclosed including detectors for detecting the presence of electromagnetic interference and setting an interference state pacing mode and pacing rate. The interference state pacing mode and pacing rate are altered as a function of patient pacemaker dependency and the prevailing mean heart rate. When pacemaker dependency exists, the pacing rate is maintained and even increased from the prevailing mean heart for the duration of the interference state. When the patient is determined to not be pacemaker dependent, pacing is inhibited or suspended for the duration of the interference state.
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Citations
6 Claims
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1. A method of operating a pacing system to respond to a presence of electromagnetic interference tending to corrupt the features of an electrogram, comprising:
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accumulating data from sense events and delivered pacing pulses over a predetermined time interval, deriving a mean heart rate from the accumulated data, and deriving a pacing dependency percentage representing the ratio of delivered pacing pulses to the sum of delivered pacing pulses and sensed events over the predetermined time interval; declaring an interference state if electromagnetic interference tending to corrupt the features of the electrogram is detected; determining whether the patient is pacemaker dependent or pacemaker independent from the pacing dependency percentage; during the declared interference state; setting a pacing mode of the pacing system to an inhibited pacing mode if the patient is determined to be pacemaker independent, whereby pacing pulses are not delivered to the heart chamber; setting the pacing mode to a fixed rate pacing mode if the patient is determined to be pacemaker dependent, whereby a pacing escape interval is not restarted by a sense event and pacing pulses are delivered to the heart chamber at a fixed rate; and adjusting the pacing escape interval to provide an interference state pacing rate exceeding the mean heart rate by a predetermined increment; and operating the pacing system in the interference state pacing mode at the interference state pacing rate, whereby the patient'"'"'s heart is paced while minimizing occurrences of parasystole. - View Dependent Claims (2, 3)
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4. A system that operates a pacing system to respond to a presence of electromagnetic interference tending to corrupt the features of an electrogram, comprising:
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means for accumulating data from sense events and delivered pacing pulses over a predetermined time interval, for deriving a mean heart rate from the accumulated data, and for deriving a pacing dependency percentage representing the ratio of delivered pacing pulses to the sum of delivered pacing pulses and sensed events over the predetermined time interval; means for declaring an interference state upon detecting electromagnetic interference tending to corrupt the features of the electrogram; means for determining whether the patient is pacemaker dependent or pacemaker independent from the pacing dependency percentage; means for setting a pacing mode of the pacing system to an inhibited pacing mode if the patient is determined to be pacemaker independent, whereby pacing pulses are not delivered to the heart chamber; means for setting the pacing mode to a fixed rate pacing mode if the patient is determined to be pacemaker dependent, whereby the pacing escape interval is not restarted by a sense event and pacing pulses are delivered to the heart chamber at a fixed rate; and means for adjusting a pacing escape interval to provide an interference state pacing rate exceeding the mean heart rate by a predetermined increment, whereby the patient'"'"'s heart is paced while minimizing occurrences of parasystole. - View Dependent Claims (5, 6)
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Specification