METHOD AND DEVICE FOR DETECTING CARDIAC CYCLE ONSET Russian patent published in 2003 - IPC

FIELD: medicine; medical engineering. SUBSTANCE: method involves twice differentiating electrocardiogram signal filtered from high frequency noise and comparing the obtained signal at two threshold levels. One level is set Δ higher than the zero line and the other one Δ lower than the zero line. Double- differentiated signal amplitude being found between the threshold levels, clock pulses counting begins. Given number N being reached, position of the last pulse from the counted ones (that is number N) on time axis is to be taken as the next cardiac cycle onset. The double-differentiated signal amplitude being found beyond the threshold levels earlier than the number N is achieved, counting is started once more. The number N is selected in a way that when counting the value could be reached only on electrocardiogram signal interval between T and P teeth. The device has in series connected filter and two differentiating units, two threshold level sources, two comparator units, clock pulse oscillator, the first, the second, the third AND- gate and pulse counter. Filter input is device input. EFFECT: high reliability in determining cardiac cycle onset notwithstanding the cardiac signal teeth deviations from norm. 2 cl, 2 dwg