ABSTRACT
To explore formation mechanism of short P‐R interval in ECG during mid‐late pregnancy and its clinical value .Methods :A total of 100 mid‐late pregnant women ,who received ECG examination in our department of elec‐trophysiology ,according to ECG results were divided into short P‐R interval group (n＝50) and normal ECG group (n＝50).The 24h heart rate variability (HRV) ,general condition of pregnant women on 12 months after childbirth and the newborn condition were observed and compared between two groups .Results :Compared with normal ECG group ,there were significant reductions in standard deviation of normal to normal RR intervals calculated over the 24h period (SDNN) [(120.6 ± 28.7)ms vs.(90.6 ± 25.8)ms] ,SDNN Index [(115.6 ± 27.6)ms vs.(79.8 ± 25.9)ms] ,root‐mean square of differences between successive normal to normal intervals (rMSSD) [(38.8 ± 13.1)ms vs.(28.7 ± 12.5)ms] ,adjacent nor‐mal RR interval difference ＞ 50ms stroke accounted for a percentage of 24h total RR interval (PNN50) [(15.6 ± 10.3)%vs.(7.9 ± 5.4)%] ,very low frequency (VLF) [(1937.7 ± 734.9)Hz vs.(996.7 ± 114.2 )Hz] ,low frequency (LF) [(579.8 ± 256.0)Hz vs.(285.7 ± 134.7) Hz] and high frequency (HF) [(341.3 ± 185.3) Hz vs.(199.6 ± 146.8)Hz] in short P‐R interval group ,P＝0.001 all.There were no significant difference in newborn condition ,incidence rates of hyper‐tension ,anemia ,tachycardia ,heart failure and short P‐R interval on 12 months after childbirth between two groups ,P＞0.05 all.Conclusion :Occurrence of short P‐R interval is a relatively normal physiological phenomenon in mid‐late pregnant women.It＇s heart rate variability change .Its mechanism is related to enhanced sympathetic excitability during pregnancy , and possesses no significant influence on newborn and women after childbirth .