R-wave detection method for implantable cardioverter defibrillators
First Claim
1. An improved detection method for sensing the occurrence of an R-wave associated with a heart beat event from electrical signals provided by at least two electrodes implanted in the heart, the method including the device implemented steps of:
- (a) receiving an electrical signal from the electrodes implanted in the heart, and (b) limiting recognition of the electrical signal as a R-wave event to those events in which the amplitude of the electrical signal exceeds a decreasing threshold level and a floor level, the improvement to step (b) comprising;
using a time constant of decay, selected from a plurality of time constants, as the decreasing threshold level, each time constant corresponding to a classification of the amplitude of the electrical sign of at least one most recent previously recognized R-wave events.
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Abstract
An ICD detection method for sensing the occurrence of an R-wave improves the ability to distinguish R-waves from noise through the use of variable declining sensitivity thresholds. The method includes the consideration of the amplitude of at least the previous most recent R-wave to determine a declining threshold of sensitivity used to recognize a subsequent electrical signal as an R-wave. In the method, the amplitude of the previous R-wave may be classified, based upon amplitude, and based upon the classification, a desirable time constant for the declining threshold of sensitivity is provided as an exponential or reverse exponential decay. Alternatively, a piece wise use of various decay formulas may be combined and used to avoid false recognition of noise as an R-wave.
243 Citations
15 Claims
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1. An improved detection method for sensing the occurrence of an R-wave associated with a heart beat event from electrical signals provided by at least two electrodes implanted in the heart, the method including the device implemented steps of:
- (a) receiving an electrical signal from the electrodes implanted in the heart, and (b) limiting recognition of the electrical signal as a R-wave event to those events in which the amplitude of the electrical signal exceeds a decreasing threshold level and a floor level, the improvement to step (b) comprising;
using a time constant of decay, selected from a plurality of time constants, as the decreasing threshold level, each time constant corresponding to a classification of the amplitude of the electrical sign of at least one most recent previously recognized R-wave events. - View Dependent Claims (2, 3, 4)
- (a) receiving an electrical signal from the electrodes implanted in the heart, and (b) limiting recognition of the electrical signal as a R-wave event to those events in which the amplitude of the electrical signal exceeds a decreasing threshold level and a floor level, the improvement to step (b) comprising;
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5. An improved detection method for sensing the occurrence of an R-wave associated with a heart beat event from electrical signals provided by at least two electrodes implanted in the heart, the method including the device implemented steps of:
- (a) receiving an electrical signal from the electrodes implanted in the heart, and (b) limiting recognition of the electrical signal as an R-wave event to those events in which the amplitude of the electrical signal exceeds a decreasing threshold level and a floor level, the improvement to step (b) comprising;
using a first decay as the decreasing threshold level from an initial threshold level to an intermediate threshold level; and using a second decay, distinct from the first decay, as the decreasing threshold level from the intermediate threshold level to the floor level. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
- (a) receiving an electrical signal from the electrodes implanted in the heart, and (b) limiting recognition of the electrical signal as an R-wave event to those events in which the amplitude of the electrical signal exceeds a decreasing threshold level and a floor level, the improvement to step (b) comprising;
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13. An improved detection method for sensing the occurrence of an R-wave associated with a heart beat event from electrical signals provided by at least two electrodes implanted proximate the heart, the method including the device-implemented steps of:
- (a) receiving an electrical signal from the electrodes, and (b) limiting recognition of the electrical signal as an R-wave event to those event in which the amplitude of the electrical signal exceeds a decreasing threshold level and a floor level, the improvement to step (b) comprising;
(b1) using a first threshold having a first sensitivity for a first portion of the decreasing threshold level; and (b2) using a second threshold having a second sensitivity for a second portion of the decreasing threshold level. - View Dependent Claims (14, 15)
- (a) receiving an electrical signal from the electrodes, and (b) limiting recognition of the electrical signal as an R-wave event to those event in which the amplitude of the electrical signal exceeds a decreasing threshold level and a floor level, the improvement to step (b) comprising;
Specification