Objective To observe and measure the changes of area under the waveform curves of invasive arterial pressure waveform（IABW） and pulse oximetry waveform（POW） before and after arrhythmia

and to explore its clinical significance. Methods The invasive arterial pressure and pulse oximetry waveform curves of 200 patients who underwent invasive arterial pressure monitoring and pulse oximetry monitoring were collected. They were divided into sinus rhythm group and arrhythmia group

and the arrhythmia group was divided into atrial presystolic group（AP）

ventricular presystolic group（VP）

atrial fibrillation group（AF） and tachyarrhythmia（supraventricular/ventricular） group.The areas under the curve of invasive arterial pressure and pulse oximetry waveform in sinus rhythm and arrhythmia were calculated respectively

and the PR and RR intervals of corresponding electrocardiogram cycles were calculated too. And LVEF

FS

LVED and other parameters of cardiac Doppler and clinical test parameters were collected.Results The area under the IABW curve in the sinus rhythm was 64.75±40.75mm2. The area under POW curve was87.05±37.46mm2. There was no significant difference between male and female. RR interval was positively correlated with the area under IABW and POW curve

with correlation coefficients γ=0.609

0.378

p<0.001

p=0.036respectively. The areas under IABW and POW curve of atrial premature

atrial fibrillation and ventricular premature were positively correlated with RR interval

but not with PR interval. The correlation coefficients between the area under the IABW curve and POW curve

and RR interval in AP group were γ=0.848

0.675

0.614 respectively

p<0.001; and the correlation coefficients during AF group were γ=0.430

0.641

0.392

p<0.001; and γ=0.820

0.554

0.714 in VP group

p<0.001. The area under the IABW curve of tachyarrhythmia was positively correlated with RR interval

and the correlation coefficient was γ=0.847

p<0.05. There was significant difference in the decrease of areas under IABW curve in tachyarrhythmia compared with cardioversion

p<0.05. Conclusions The area under the curve of invasive arterial pressure waveform and pulse oximetry waveform is significantly different in different arrhythmias. The areas under IABW and POW curve of atrial premature

atrial fibrillation and ventricular premature were positively correlated with RR interval

but not with PR interval. The areas under IABW curve is positively correlated with the area under the POW curve. And the area under the IABW curve of tachyarrhythmia was positively correlated with RR interval. There was significant difference in the decrease of areas under IABW curve in tachyarrhythmia compared with cardioversion. Therefore

we can immediately evaluate the impact of arrhythmia on stroke output by observing and estimating the changes of area under the curve of IABW and POW. Combined with invasive blood pressure

we can timely understand the impact of arrhythmia on hemodynamics

and timely adjust RR interval can improve stroke output and hemodynamics in tachyarrhythmia

which has great clinical significance.