초록 ▼

Cardiac activity is sensed over a plurality of heart beats defining a beat set. For each beat in the set, it is determined whether the beat is a non-classified beat (e.g., paced beat, a beat outside of a specified heart rate range or a PVC), or a classified beat. For each classified beat, it is dete

Cardiac activity is sensed over a plurality of heart beats defining a beat set. For each beat in the set, it is determined whether the beat is a non-classified beat (e.g., paced beat, a beat outside of a specified heart rate range or a PVC), or a classified beat. For each classified beat, it is determined whether the beat is a non-detect beat, a minor beat or a major beat. Counts of classified beats, non-classified beats, major beats, minor beats, and non-detect beats are maintained. The beat set is declared to be one of a non-classified set, a major set, a minor set or a non-detect set based on the relative counts of classified beats, non-classified beats, major beats, minor beats, and non-detect beats. Over a period of time, counts of beat-set types are maintained and entry into and exit from ST episodes are determined based on these beat-set counts.

대표청구항 ▼

1. A method of monitoring ST segments, said method comprising: sensing electrical cardiac activity over a plurality of heart beats defining a beat set;for each beat in the beat set, determining whether the beat of the ST segment is a non-classified beat or a classified beat;for each classified beat,

1. A method of monitoring ST segments, said method comprising: sensing electrical cardiac activity over a plurality of heart beats defining a beat set;for each beat in the beat set, determining whether the beat of the ST segment is a non-classified beat or a classified beat;for each classified beat, determining whether the beat is a non-detect beat, a minor beat or a major beat;maintaining a count of classified beats, a count of non-classified beats, a count of major beats, a count of minor beats, and a count of non-detect beats;declaring the beat set to be one of a non-classified set, a major set, a minor set or a non-detect set based on the relative counts of classified beats, non-classified beats, major beats, minor beats, and non-detect beats. 2. The method of claim 1 wherein determining whether the beat is a non-detect beat, a minor beat or a major beat comprises: comparing the ST segment shift of the beat to each of a minor threshold and a major threshold;determining the beat is a non-detect beat if the ST segment shift does not exceed the minor threshold;determining the beat is a minor beat if the ST segment shift is at or above the minor threshold; anddetermining the beat is a major beat if the ST segment shift is at or above the major threshold. 3. The method of claim 1 wherein a beat set is declared a non-classified set if the count of non-classified beats reaches a non-classified-beat value before the count of classified beats reaches a classified-beat value. 4. The method of claim 3 wherein the plurality of heart beats is Z, the classified-beat value is Y and the non-classified beat value is Z−Y+1. 5. The method of claim 1 wherein a beat set is declared a major set if the count of classified beats reaches a classified-beat value before the count of non-classified beats reaches a non-classified-beat value, and the count of major beats reaches a major-beat value before either of the count of minor beats and the count of non-detect beats reaches its respective minor-beat value and non-detect beat value. 6. The method of claim 5 wherein: the plurality of heart beats is Z, the classified-beat value is Y and the non-classified-beat value is Z−Y+1; andthe major-beat value is X, the minor beat value is X and the non-detect beat value is Y−X+1. 7. The method of claim 1 wherein a beat set is declared a minor set if the count of classified beats reaches a classified-beat value before the count of non-classified beats reaches a non-classified-beat value, and the count of minor beats reaches a minor-beat value before either of the count of major beats and the count of non-detect beats reaches its respective major-beat value and non-detect beat value. 8. The method of claim 7 wherein: the plurality of heart beats is Z, the classified-beat value is Y and the non-classified-beat value is Z−Y+1; andthe major-beat value is X, the minor-beat value is X and the non-detect-beat value is Y−X+1. 9. The method of claim 1 wherein a beat set is declared a non-detect set if the count of classified beats reaches a classified-beat value before the count of non-classified beats reaches a non-classified-beat value, and the count of non-detect beats reaches a non-detect-beat value before either of the count of major beats and the count of minor beats reaches its respective major-beat value and minor-beat value. 10. The method of claim 9 wherein: the plurality of heart beats is Z, the classified-beat value is Y and the non-classified-beat value is Z−Y+1; andthe major-beat value is X, the minor-beat value is X and the non-detect-beat value is Y−X+1. 11. The method of claim 1 further comprising maintaining a count of major sets, a count of minor sets, a count of non-detect sets and a count of non-classified sets. 12. The method of claim 11 wherein the count of major sets is incremented upon declaration of a major set and is initialized upon declaration of a non-detect set. 13. The method of claim 12 further comprising detecting a major ST episode onset when the count of major sets reaches a nominal value. 14. The method of claim 13 wherein upon declaration of a major ST episode, detecting an ST episode exit when a first number of non-classified sets are declared or a second number of non-detect sets are declared. 15. The method of claim 11 wherein the count of minor sets is incremented upon declaration of a major set or declaration of a minor set, and is initialized upon declaration of a non-detect set. 16. The method of claim 15 further comprising detecting a minor ST episode onset when the count of minor sets reaches a nominal value. 17. The method of claim 16 wherein upon declaration of a minor ST episode, detecting an ST episode exit when a first number of non-classified sets are declared or a second number of non-detect sets are declared. 18. The method of claim 11 wherein the count of non-detect sets is incremented upon declaration of a non-detect set, and is initialized upon declaration of a major set or declaration of a minor set. 19. The method of claim 11 wherein the count of non-classified sets is incremented upon declaration of a non-classified set. 20. The method of claim 1 wherein a non-classified beat corresponds to anyone of a paced beat, a beat outside of a specified heart rate range or a PVC. 21. A device for monitoring ST segments, said device comprising: a sensor configured to sense electrical cardiac activity over a plurality of heart beats defining a beat set; anda processor configured to: for each beat in the beat set, determine whether the beat is a non-classified beat or a classified beat;for each classified beat, determine whether the beat of the ST segment is a non-detect beat, a minor beat or a major beat;maintain a count of classified beats, a count of non-classified beats, a count of major beats, a count of minor beats, and a count of non-detect beats;declare the beat set to be one of a non-classified set, a major set, a minor set or a non-detect set based on the relative counts of classified beats, non-classified beats, major beats, minor beats, and non-detect beats.