Active medical device, in particular an implantable defibrillator, with detection of QRS complexes in a signal with a lot of interference

摘要

The device has a digital block (18) comprising a dual-threshold comparator (30) to deliver a peak detection indicator at output (40) when amplitude (A) of input electrogram signal exceeds amplitude threshold (SA) i.e. variable adaptive threshold, when the threshold exceeds during a duration. A peak amplitude threshold determination unit i.e. adder (34), combines a preset low threshold value (A0) with a variable value of noise level of the signal. A determination unit (32) determines the variable value from root mean square (RMS) of noise in the signal except signal peak detection periods.