Analysis of heart rate variability in children with ventricular premature beat

Objective To explore the heart rate variability (HRV) of dynamic electrocardiogram in children with benign or malignant ventricular premature beat (VPB) and healthy children, and analyze the changes of time and frequency domain indexes of HRV. Methods From January 2012 to December 2017, a total of 100 children with VPB diagnosed by auxiliary examinations and follow-up visits results, who were 6-14 years old and accepted dynamic electrocardiogram test in West China Second University Hospital, Sichuan University were recruited in this study. According to benign or malignant VPB, they were divided into benign VPB group (n=50) and malignant VPB group (n=50). Children in malignant VPB group were all combined with organic heart diseases, such as congenital heart defects (4 cases), dilated cardiomyopathy (DCM) (9 cases ), and viral myocarditis (37 cases) diagnosed by abnormal myocardial enzyme levels. Meanwhile, 50 cases of healthy children with the same age range who received dynamic electrocardiogram in the same hospital during the same period and the results were normal were included into control group. Measurement data with normal distribution and homogeneity such as standard deviation of all normal-to-normal intervals (SDNN), standard deviation of average normal-to-normal intervals (SDANN), root mean square of the successive difference (rMSSD), percentage normal-to-normal interval deviation greater than 50 ms (PNN50), coefficient of variance (CV), coefficient of variance (ULF), very-low frequencies (VLF), low frequencies (LF), and high frequencies (HF) were expressed by ±s. And those data among 3 groups were compared by one-way ANOVA, further comparisons between each two groups were conducted by least singnificant difference (LSD) test. Numeration data such as constituent ratio of genders were expressed by rate (%), and were compared by chi-square test among 3 groups. There were no significant differences among 3 groups in the constituent ratio of gender and age (P>0.05). This study met the requirements of the World Medical Association Declaration of Helsinki revised in 2013. Clinical informed consent was obtained from each child′s guardians. Results There were significant differences among 3 groups in HRV analysis results of time domain indicators such as SDNN, SDANN, rMSSD, PNN50, CV, and frequency domain indicators such as ULF, VLF, LF and HF (F=42.304, 14.144, 26.344, 15.362, 8.115, 18.031, 10.611, 20.928, 13.719; P 0.05), and PNN50 and HF between benign VPB group and control group (P>0.05), but there were significant differences in the others time domain indicators and frequency domain indicators of HRV between each two groups (P<0.05). Conclusions The HRV analysis of dynamic electrocardiogram is helpful in determining benign and malignant VPB in children. However, prospective randomized controlled trials with multicenter and large-sample size are needed to evaluate whether the HRV analysis can be used to determine the severity of VPB and as a prognosis marker in children with VPB. Key words: Arrhythmias, cardiac; Ventricular premature complexes; Heart rate variability; Electrocardiography; Controlled clinical trial; Child