Method of and apparatus for classifying arrhythmias using scatter plot analysis
First Claim
1. A computer-readable medium programmed with instructions for performing a method of classifying arrhythmias, the medium comprising instructions for causing a programmable processor to:
- acquire a cardiac signal;
derive a recurring cardiac rhythm parameter from the cardiac signal and storing the parameter as a series of values;
plot a point on a scatter plot for each pair of successive stored values, wherein an abscissa of the point is a first value of a pair of successive stored values, and an ordinate of the point is a second value of the pair of successive stored values, and wherein the scatter plot is divided into a plurality of regions;
derive a measure of variability by counting the number of regions that have one or more points plotted therein; and
compare the measure of variability to a threshold.
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Abstract
A method of classifying arrhythmias using scatter plot analysis to define a measure of variability of a cardiac rhythm parameter such as for example, without limitation, R-R interval, A-A interval, and the slope of a portion of a cardiac signal, is disclosed. The variability measurement is derived from a scatter plot of a cardiac rhythm parameter, employing a region counting technique that quantifies the variability of the cardiac rhythm parameter while minimizing the computational complexity. The method may be employed by an implantable medical device or system, such as an implantable pacemaker or cardioverter defibrillator, or by an external device or system, such as a programmer or computer. The variability measurement may be correlated with other device or system information to differentiate between atrial flutter and atrial fibrillation, for example. The variability information may also be used by the device or system to select an appropriate therapy for a patient.
130 Citations
20 Claims
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1. A computer-readable medium programmed with instructions for performing a method of classifying arrhythmias, the medium comprising instructions for causing a programmable processor to:
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acquire a cardiac signal;
derive a recurring cardiac rhythm parameter from the cardiac signal and storing the parameter as a series of values;
plot a point on a scatter plot for each pair of successive stored values, wherein an abscissa of the point is a first value of a pair of successive stored values, and an ordinate of the point is a second value of the pair of successive stored values, and wherein the scatter plot is divided into a plurality of regions;
derive a measure of variability by counting the number of regions that have one or more points plotted therein; and
compare the measure of variability to a threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A system for classifying arrhythmias, the system comprising:
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a sensor for acquiring a cardiac signal;
first processing means for deriving a recurring cardiac rhythm parameter from the cardiac signal and storing the parameter as a series of values;
a database for plotting a point on a scatter plot for each pair of successive stored values, wherein an abscissa of the point is a first value of a pair of successive stored values, and an ordinate of the point is a second value of the pair of successive stored values, and wherein the scatter plot is divided into a plurality of regions;
second processing means for deriving a measure of variability by counting the number of regions that have one or more points plotted therein; and
a comparator for comparing the measure of variability to a threshold.
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18. An implantable medical device (IMD) for classifying arrhythmias, the IMD comprising:
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means for acquiring a cardiac signal;
means for deriving a recurring cardiac rhythm parameter from the cardiac signal and storing as a series of values;
means for recording a point in a data bin for each pair of successive stored values, wherein an abscissa of the point is a first value of a pair of successive stored values, and an ordinate of the point is a second value of the pair of successive stored values, and wherein the data bin is selected from a plurality of data bins based on the first and second values of the point;
means for deriving a measure of variability by counting the data bins that have one or more points recorded therein; and
means for comparing the measure of variability to a threshold to classify an arrhythmia. - View Dependent Claims (19, 20)
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Specification