Method and apparatus for detecting arrhythmias in a medical device

A method of treating a cardiac event with a medical device having therapeutic componentry and a plurality of electrodes, comprising:

• sensing cardiac signals from the plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector;
• determining a first characteristic of the cardiac signals sensed by the first sensing vector over a predetermined sensing window and a first characteristic of the cardiac signals sensed by the second sensing vector over the predetermined sensing window;
• determining a second characteristic of the cardiac signals sensed by the first sensing vector different from the first characteristic of the first sensing vector over the predetermined sensing window and a second characteristic of the cardiac signals sensed by the second sensing vector different from the first characteristic of the second sensing vector over the predetermined sensing window;
• determining a third characteristic of the cardiac signals sensed by the first sensing vector different from the first characteristic of the first sensing vector and the second characteristic of the first sensing vector over the predetermined sensing window and a third characteristic of the cardiac signals sensed by the second sensing vector different from the first characteristic of the second sensing vector and the second characteristic of the second sensing vector over the predetermined sensing window;
• and
• delivering a therapy from the therapeutic componentry based, at least in part, on:
• a minimum one of the first characteristic of the cardiac signals sensed by the first sensing vector and the first characteristic of the cardiac signals sensed by the second sensing vector;
• a minimum one of the second characteristic of the cardiac signals sensed by the first sensing vector and the second characteristic of the cardiac signals sensed the second sensing vector;
• and
• a maximum one of the third characteristic of the cardiac signals sensed by the first sensing vector and the third characteristic of the cardiac signals sensed by the second sensing vector.

A non-transitory computer readable medium having computer executable instructions for performing a method of treating a cardiac event with a medical device having therapeutic componentry and a plurality of electrodes comprising:

• sensing cardiac signals from the plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector;
• determining a first characteristic of the cardiac signals sensed by the first sensing vector over a predetermined sensing window and a first characteristic of the cardiac signals sensed by the second sensing vector over the predetermined sensing window;
• determining a second characteristic of the cardiac signals sensed by the first sensing vector different from the first characteristic of the first sensing vector over the predetermined sensing window and a second characteristic of the cardiac signals sensed by the second sensing vector different from the first characteristic of the second sensing vector over the predetermined sensing window;
• determining a third characteristic of the cardiac signals sensed by the first sensing vector different from the first characteristic of the first sensing vector and the second characteristic of the first sensing vector over the predetermined sensing window and a third characteristic of the cardiac signals sensed by the second sensing vector different from the first characteristic of the second sensing vector and the second characteristic of the second sensing vector over the predetermined sensing window;
• delivering a therapy from the therapeutic componentry based, at least in part, on:
• a relationship of one of the first characteristic sensed by the first sensing vector and the first characteristic sensed by the second sensing vector and one of the second characteristic sensed by the first sensing vector and the second characteristic sensed by the second sensing vector;
• and
• a relationship of one of the first characteristic sensed by the first sensing vector and the first characteristic sensed by the second sensing vector and one of the third characteristic sensed by the first sensing vector and the third characteristic sensed by the second sensing vector.

A method of detecting a cardiac event in a medical device, comprising:

• sensing cardiac signals from a plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector;
• determining a first characteristic in response to the cardiac signals sensed along the first sensing vector over a predetermined sensing window and in response to the cardiac signals sensed along the second sensing vector over the predetermined sensing window;
• determining a second characteristic in response to the cardiac signals sensed along the first sensing vector over the predetermined sensing window and in response to the cardiac signals sensed alone he second sensing vector over the predetermined sensing window;
• determining a third characteristic in response to the cardiac signals sensed along the first sensing vector over the predetermined sensing window and in response to the cardiac signals sensed along the second sensing vector over the predetermined sensing window;
• defining a second shock zone in response to the first characteristic associated with a predetermined one of the first sensing vector and the second sensing vector and the second characteristic associated with a predetermined one of the first sensing vector and the second sensing vector;
• defining a first shock zone in response to the first characteristic associated with a predetermined one of the first sensing vector and the second sensing vector and the third characteristic associated with a predetermined one of the first sensing vector and the second sensing vector;
• and
• detecting the sensed cardiac signals as being associated with the event in response to the first shock zone and the second shock zone;
• wherein defining a first shock zone comprises:
• determining a minimum of the first characteristic associated with the first sensing vector and the first characteristic associated with the second sensing vector;
• determining a minimum of the second characteristic associated with the first sensing vector and the second characteristic associated with the second sensing vector;
• and
• defining a first boundary associated with the minimum of the first characteristic and the minimum of the second characteristic;
• wherein defining a first shock zone comprises:
• determining a minimum of the first characteristic associated with the first sensing vector and the first characteristic associated with the second sensing vector:
• determining a minimum of the second characteristic associated with the first sensing vector and the second characteristic associated with the second sensing vector;
• and
• defining a first boundary associated with the minimum, of the first characteristic and the minimum of the second characteristic;
• wherein detecting the sensed cardiac signals comprises:
• determining whether the minimum of the first characteristic is less than the first boundary;
• determining whether the maximum of the third characteristic is greater than the second boundary;
• identifying the both the first sensing vector and the second sensing vector as being shockable in response to both the minimum of the first characteristic being less than the first boundary and the maximum of the third characteristic being greater than the second boundary;
• and
• identifying the both the first sensing vector and second sensing vector as being not shockable in response to one of the minimum of the first characteristic not being less than the first boundary and the maximum of the third characteristic not being greater than the second boundary;
• and
• wherein the first characteristic corresponds to low slope content, the second characteristic corresponds to spectral width, and the third characteristic corresponds to a normalized mean rectified amplitude.