Method for diagnosing cardiac arrhythmias using interval irregularity
First Claim
1. A method for analyzing a cardiac rhythm, including the steps of:
- detecting a patient'"'"'s cardiac activity, said cardiac activity including successive heartbeats, and providing a sequence of cardiac intervals which are measures for the time between sequential ones of said successive heartbeats;
selecting a window containing a predetermined number N of successive cardiac intervals;
ignoring a predetermined number n of the shortest and longest ones of said intervals where 0≦
n<
N/2; and
taking the difference between the remaining longest and shortest intervals where said difference provides a measure of interval irregularity whereby said measure of interval irregularity is indicative of whether the cardiac rhythm is of supraventricular or ventricular origin.
1 Assignment
0 Petitions
Accused Products
Abstract
A method for detecting or classifying cardiac arrhythmias using interval irregularity. The method includes the steps of detecting a patient'"'"'s cardiac activity and looking at a first selected criterion such as the patient'"'"'s heart rate exceeding a preset rate threshold to determine if a tachycardia is present. When the first criterion is met, a window of N successive cardiac intervals is selected for analysis. A selected number of the shortest and longest intervals are ignored and the difference between the remaining longest and shortest intervals is calculated to provide a measure of interval irregularity indicative of the origin of the cardiac rhythm. In one embodiment, a parameter n is set such that 0≦n<N/2, and the intervals in the window are ordered from shortest to longest with the shortest being interval 1 and the longest being interval N. The difference between interval N-n and interval n+1 is then computed to provide a measure of interval irregularity which is indicative of the origin of a cardiac rhythm. For example, if n=1, the longest and shortest of the intervals in a window of intervals are discarded, and the difference between the duration of the second longest and second shortest is calculated and this difference is a measure of interval irregularity. The difference is compared to a selected irregularity threshold and if the difference is greater than the threshold, the rhythm is considered irregular. If the difference is less than or equal to the irregularity threshold, the rhythm is considered regular.
-
Citations
6 Claims
-
1. A method for analyzing a cardiac rhythm, including the steps of:
-
detecting a patient'"'"'s cardiac activity, said cardiac activity including successive heartbeats, and providing a sequence of cardiac intervals which are measures for the time between sequential ones of said successive heartbeats; selecting a window containing a predetermined number N of successive cardiac intervals; ignoring a predetermined number n of the shortest and longest ones of said intervals where 0≦
n<
N/2; andtaking the difference between the remaining longest and shortest intervals where said difference provides a measure of interval irregularity whereby said measure of interval irregularity is indicative of whether the cardiac rhythm is of supraventricular or ventricular origin. - View Dependent Claims (2, 3)
-
-
4. A method for analyzing a cardiac rhythm, comprising the steps of:
-
detecting a patient'"'"'s cardiac activity including a sequence of successive cardiac intervals; determining from said detected cardiac activity a heart rate for said patient and determining if said patient'"'"'s heart rate exceeds a preselected tachycardia rate threshold; if said patient'"'"'s heart rate exceeds said preselected tachycardia rate threshold, selecting a window of successive cardiac intervals; ignoring a predetermined number of the shortest and longest ones of said intervals in said window; and taking the difference between the remaining longest and shortest intervals to provide a measure of interval irregularity.
-
-
5. A method for providing a measure of cardiac interval irregularity, including the steps of:
-
detecting a patient'"'"'s cardiac activity including a sequence of heartbeats and providing a sequence of intervals that are measures for the time between successive heartbeats; ignoring a preselected number of the shortest and longest ones of said intervals; and taking the difference between the remaining longest and shortest intervals to provide a measure of interval irregularity. - View Dependent Claims (6)
-
Specification