Brady pause detection for implantable cardiac monitors

An apparatus comprising:

• a cardiac signal sensing circuit configured to receive a sensed cardiac signal and produce a sampled cardiac signal representative of electrical cardiac activity of a subject;
• a buffer memory configured to store at least a portion of the sampled cardiac signal;
• and
• a pause detection circuit electrically coupled to the cardiac signal sensing circuit and the buffer memory and configured to:
• identify ventricular depolarization R-waves in at least one of the sensed cardiac signal or the sampled cardiac signal;
• detect a candidate pause episode in which delay between identified R-waves exceeds a specified delay threshold and time a specified intra-pause duration in response to the detecting;
• calculate an intra-pause threshold of amplitude for signal samples obtained during the intra-pause duration;
• identify signal samples during the intra-pause duration that exceed the intra-pause threshold;
• and
• discard the candidate pause episode or store the candidate pause episode as a bradycardia pause episode according to the identified number of signal samples.

An apparatus comprising:

• a cardiac signal sensing circuit configured to receive a sensed cardiac signal and produce a sampled cardiac signal representative of electrical cardiac activity of a subject;
• a buffer memory configured to store at least a portion of the sampled cardiac signal;
• and
• a pause detection circuit electrically coupled to the cardiac signal sensing circuit and the buffer memory and configured to:
• identify ventricular depolarization in the sampled cardiac signal;
• detect a candidate pause episode in which delay in ventricular depolarization exceeds a specified delay threshold;
• and
• discard the candidate pause episode when detecting that the cardiac signal was not sensed during the candidate pause episode, otherwise store the candidate pause episode as a bradycardia pause episode.