Method for determining a metric of non-sustained arrhythmia occurrence for use in arrhythmia prediction and automatic adjustment of arrhythmia detection parameters
An implantable medical device and associated method are provided for detecting non-sustained arrhythmias and determining a metric of non-sustained arrhythmias. The metric may be used for predicting the occurrence of a sustained arrhythmia or for automatically adjusting the parameters used for detecting a sustained arrhythmia.
1. A method for determining a metric of the occurrence of non-sustained arrhythmias comprising;
detecting non-sustained arrhythmia episodes as episodes;
storing characteristic data related to the non-sustained arrhythmia; and
calculating a metric of non-sustained arrhythmias based on the stored data; and
adjusting a parameter for detecting a sustained arrhythmia based on the metric of non-sustained arrhythmia occurrence, wherein stored characteristic data includes one of a number of non-sustained arrhythmia episodes within a specified period of time, a duration of a non-sustained arrhythmia episode, a cycle length during a non-sustained arrhythmia episode, and a cardiac signal morphology during a non-sustained arrhythmia episode.
2. The method according to claim 1 , further including a method for predicting the occurrence of a sustained arrhythmia based on the metric of non-sustained arrhythmias comprising:
calculating an arrhythmia risk score based on a metric of non-sustained arrhythmias;
comparing the risk score to a predefined or automatically updated threshold criteria; and
predicting that a sustained arrhythmia is likely to occur with a high probability if the risk score meets or exceeds the threshold criteria.
3. The method according to claim 2 , further including delivering a preventative therapy if a sustained arrhythmia is predicted to occur.
4. The method according to claim 2 , further including adjusting the threshold criteria based on a detected sustained arrhythmia.
5. The method according to claim 1 , wherein the parameter for detecting a sustained arrhythmia is adjusted by increasing the number of cardiac cycle intervals occurring in an arrhythmia detection zone required to detect a sustained arrhythmia.
6. The method according to claim 5 , wherein the parameter is adjusted by varying the duration of non-sustained arrhythmia episodes.