Patent ID: 8204582

Claim:
A method of generating a trigger from an R wave of an electrocardiogram (ECG) waveform using a threshold that adapts to the slope of the R wave during a leading edge of the R wave, the method comprising using a processing unit for: a) setting a threshold for the trigger, where the threshold is a percentage of the amplitude of the expected R wave; b) measuring slopes of the R wave over successive small time periods during the leading edge of the R wave; where slopes corresponding to waveforms that include frequencies greater than the expected R wave prevent generation of a trigger; c) adjusting the threshold for the trigger for the R wave during the leading edge of the R wave, where the threshold is increased if the slopes measured in b) are greater than expected for the R wave; d) applying a scalar value to the slopes measured in b) to set a frequency above which signal frequencies are not considered valid for recognition as an R wave; and e) generating a trigger during the leading edge of the R wave when the amplitude of the R wave reaches the threshold.