The Alterations Of Heart Rate Variability And Its Relationship With Renin-Angiotensin-Aldosterone System In Infants And Young Children With Paroxysmal Supraventricular Tachycardia

Background and Objectives Paroxysmal supraventricular tachycardia(PSVT)is a common arrhythmia in infants and young children.It can break out recurrently and result in heart failure if lasts more than 24 hours.It' recurrent attacks severely influenced physical and mental health of children.Heart rate variability(HRV)is a quantitative method for assessing cardiovascular autonomic nerve system function so far.Renin-angiotensin-aldosteron system(RAAS)is an important humoral factor to regulate cardiovascular activity,and it's an indirect proof of sympathetic nervous system activation.This study aims at exploring the alterations of heart rate variability and its relationship with plasma renin-angiotensin-aldosterone system,in infants and young children with paroxysmal supraventricular tachycardia(PSVT)Methods The study included 28 children with PSVT admitted in pediatric department of Shandong provincial hospital and 30 age-matched healthy children in out-patient clinic examination during September in 2005 to may in 2007.There were 16 male patients and 12 female patients in patient group,the age are between 1 month to 30 months.There were 16 boys and 14 girls in normal control group,the age are between 1 month to 32 months.All children underwent detection of CK-MB,CTnI, and trans-thoracic echocardiography to exclude the myocarditis,myocardiopathy and other organic heart disease.All patients admitted in hospital were administrated with Propafenone firstly,the none responder were administrated with Amiodarone. The peripheral blood of the patients were collected before breakfast tomorrow morning and all patients underwent 24 hours holter monitoring and HRV analysis. The plasma renin,angiotensinⅡand aldosterone were detected by radioimmunity. The patients in normal control group collected peripheral blood and underwent 24 hours holter and HRV analysis.HRV analysis mainly included long-term time domain index such as the standard deviation of the NN intervals(SDNN),the standard deviation of all mean 5-minute NN intervals(SDANN),the square root of the mean squared differences of successive NN intervals(rMSSD),the pencentage of the number of interval differences of successive NN intervals greater than 50ms in total number of NN intervals(PNN50).Results1.There were 1 to 10 times in the patients with PSVT during 24 hours holter monitoring and the longest time lasts for less than 60 minutes.The normal control group children didn't happened.2.The SDNN of patients with PSVT decreased than the normal control group(65.03±14.34ms Vs 77.17±13.27ms,p＜0.01).The rMSSD of patients with PSVT decreased significantly than the normal control group(21.82±5.87ms Vs 27.61±6.30ms,p＜0.01).The PNN50%of patients with PSVT decreased significantly than the normal control group(4.35±2.11 Vs 8.61±2.05,p＜0.01).The SDANN of patients with PSVT increased than the normal control group,but there were no statistical significance(56.29±15.20ms Vs 52.44±14.20ms,p=0.448).3.The level of plasma renin in patients with PSVT increased than the normal control children(1.99±0.84ng/ml,h Vs 1.79±0.54ng/ml.h,p＞0.05).The level of plasma angiotensinⅡin patients with PSVT increased significantly than the normal control children(195.41±75.66pg/ml Vs 99.15±18.36pg/ml,p＜0.01).The level of plasms aldosterone in patients with PSVT increased than the normal control children but there were no statistical significance(143.60±48.32pg/ml Vs 129.99±44.82pg/ml,p＞0.05).4.The HRV index had good correlation with part of RAAS index.SDNN,rMSSD, PNN50 were negative correlated with plasma angiotensinⅡ(r=-0.438,p＜0.01; r=-0.592,p＜0.01;r=-0.786,p＜0.01,respectively).SDNN,rMSSD and PNN50 had no obvious correlation with plasma renin and aldosterone.Conclusions1.The HRV index such as SDNN,rMSSD and PNN50 all decreased in patients with PSVT,it suggested that the activity of autonomic nerve especially vagus nerve decreased.2.The level of plasma rennin,angiotensinⅡand aldosterone increased in patients with PSVT,it suggested that the RAAS had been activated and the sympathetic nervous tensions increased.3.The HRV index such as SDNN,rMSSD and PNN50 had good correlation with plasma level of angiotensinⅡin patients with PSVT,it suggested that the HRV alterations in concordance with RAAS alterations.In a word,the HRV index was a good method for assessing the alterations of autonomic nerve activity of patients with PSVT.