A device for reducing noise in signals having successive substantially
repetitive portions, comprising: an iterative averager operative to
superimpose and average said substantially repetitive portions to produce
a running average thereof, and an iteration ender comprising a noise
analyzer for determining a noise level in said running average and ending
operation of said iterative averager when said noise level reaches a
predetermined level. Also, a method of obtaining an indication of
ischemia in a patient using an ECG signal therefrom, the method
comprising: extracting an ECG signal over a duration, extracting from
said ECG signal a series of QRS complexes over said duration, extracting
high frequency components of said QRS complexes, analyzing said high
frequency components over said duration for at least one of a
predetermined quality, and inferring from said predetermined quality an
indication of ischemia.