Methods and systems for storage, retrieval, and visualization of signals and signal features

An implantable device, comprising:

• a memory;
• and
• a processor coupled to the memory and configured to perform actions, comprising:
• receiving electrical signals from tissue of a patient;
• and
• in response to each of a plurality of triggers, determining at least one feature of the received electrical signals, wherein at least one of the at least one feature is selected from an area under a curve of the received electrical signal;
• a range of an amplitude of the curve in a defined time window;
• a length of the curve of the received electrical signal;
• an energy content of the received electrical signal;
• a range of a derivative of the received electrical signal in a predefined time window;
• a time delay of a specified signal peak of the received electrical signal;
• power of the received electrical signal in a predefined frequency band;
• variation of a frequency peak with highest energy in the received electrical signal in a predefined frequency band;
• coherence changes in the received electrical signal;
• a quality factor for a specified signal peak of the received electrical signal in a predefined time window;
• full width at half amplitude (FWHM) for a specified signal peak of the received electrical signal in a predefined time window;
• entropy of the received electrical signal;
• or spectral entropy of the received electrical signal;
• storing the at least one feature in the memory on a first-in-first-out basis;
• and
• in response to each of the plurality of triggers, storing a portion of the received electrical signals, occurring after the trigger and extending for a limited duration, in the memory on a first-in-first-out basis, wherein the limited duration is divided into at least a first segment and a second segment, wherein storing the portion of the received electrical signals comprises storing a first portion of the received electrical signals during the first segment at a first sampling rate and storing a second portion of the received electrical signals during the second segment at a second sampling rate that is lower than the first sampling rate.