R-wave detection method

1. A method for detecting an R-wave from an ECG signal derived from a living body, the ECG signal including a plurality of ECG channel signals, the method comprising the steps of:

providing a plurality of channel R-wave detectors each processing a distinct signal of the plurality of channel ECG signals to generate a distinct channel trigger signal of a plurality of channel trigger signals;

inputting each channel trigger signal into a composite R-wave detector to generate a composite R-wave trigger,

whereby the composite R-wave detector more accurately detects R-waves than each of the plurality of channel R-wave detectors.

2. The method of claim 1 wherein each of the plurality of channel trigger signals is an input to a trigger-window filter, and a composite trigger output of the composite R-wave detector is triggered by a channel trigger signal from any one of the channel R-wave detectors, all channel trigger signals for the other channel R-wave detectors not triggering the composite R-wave detector for a predetermined time period after the composite R-wave detector trigger output is triggered.

3. The method of claim 2 wherein the channel trigger signal triggering the composite R-wave detector is the first-received channel trigger signal after the predetermined time period has ended.

4. The method of claim 1 wherein each of the plurality of channel trigger signals is an input to an OR-gate the output of which is the trigger output of the composite R-wave detector.

5. The method of claim 4 wherein each channel trigger signal includes a single pulse of predetermined duration for each R-wave detected by its corresponding channel R-wave detector, and the composite R-wave detector trigger output is triggered by the leading edge of the OR-gate output.

6. The method of claim 1 wherein each channel R-wave detector performs the steps of:

acquiring its corresponding ECG channel signal from the living body;

digitizing its corresponding ECG channel signal into a corresponding digital ECG channel signal;

filtering its corresponding digital ECG channel signal with a bandpass filter and applying an absolute value filter thereto to create a corresponding filtered ECG channel signal;

for each sequential value of its corresponding filtered ECG channel signal, comparing the filtered signal to an ECG tracking threshold (TT),

applying the computation TT=TT p +c 2 (ST-TT p ) where TT p is the previous value of TT, c 2 is a constant, and ST is a fraction (c 1 ) of the maximum value of its corresponding filtered ECG channel signal during a previous predetermined time period (t m );

if the corresponding filtered ECG signal is no greater than TT, incrementing a corresponding counter, but if greater than TT, setting its corresponding counter to zero; and

if no channel trigger has occurred for a predetermined dropout period (t D ), then setting TT to ST; and

comparing its corresponding counter value to a predetermined refractory count RC and, if its corresponding counter value is equal to RC, outputting a channel trigger.

7. The method of claim 6 wherein each of the plurality of channel R-wave detectors has the same settings for c 1 , c 2 , t m , t D , and RC.

8. The method of claim 6 wherein each of the plurality of channel trigger signals is an input to an OR-gate the output of which is the trigger output of the composite R-wave detector.

9. The method of claim 8 wherein each channel trigger signal includes a single pulse of predetermined duration for each R-wave detected by its corresponding channel R-wave detector, and the composite R-wave detector is triggered by the leading edge of the OR-gate output.