QRS detection and bracketing

A method for use in cardiac evaluation comprising:

• monitoring electrical activity from tissue of a patient using a plurality of external electrodes to generate a plurality of electrical signals over time;
• filtering the plurality of electrical signals using a first filter having a first frequency range to generate a plurality of first filtered signals;
• filtering the plurality of electrical signals using a second filter having a second frequency range different than the first frequency range to generate a plurality of second filtered signals;
• detecting at least one QRS complex based on the plurality of first filtered signals;
• detecting a QRS peak based on the plurality of second filtered signals and the detected at least one QRS complex;
• generating a dispersion signal from the plurality second filtered signals, wherein the dispersion signal is representative of the dispersion of the plurality second filtered signals over time;
• determining a first derivative signal based on the dispersion signal;
• and
• determining a QRS onset time value and a QRS offset time value corresponding to the at least one QRS complex based on the first derivative signal.

A system for use in cardiac evaluation comprising:

• an electrode apparatus comprising a plurality of external electrodes to be disposed proximate a patient's skin;
• and
• a computing apparatus comprising processing circuitry, the computing apparatus operably coupled to the electrode apparatus and configured to:
• monitor electrical activity from tissue of a patient using the plurality of external electrodes to generate a plurality of electrical signals over time;
• filter the plurality of electrical signals using a first filter and a second filter to generate a plurality of first filtered signals and plurality of second filtered signals, the first filter and the second filter having different frequency ranges;
• detect a QRS peak based on the plurality of first and second filtered signals,
• generate a dispersion signal from the plurality second filtered signals, wherein the dispersion signal is representative of the dispersion of the plurality second filtered signals over time;
• determine a first derivative signal based on the dispersion signal;
• determine a QRS onset time value and a QRS offset time value corresponding to the at least one QRS complex based on the first derivative signal.