P-204 Heart failure and heart rate variabilityin children with second type atrial septal defect

2003 Europace  
effect on cardiac autonomic regulation and through electmphysiologic effects on heart cell membranes. Heart rate variability (HRV) and baroreflex sensitivity (BRS) reflect cardiac autonomic regulation; reduced values predict arhythmic events and mortality. Effects of n-3 fatty acids on these risk indicators of arrhythmia have not widely been studied. A standard electrocardiogram (ECG) may be used to detect clues as to the mechanism by which n-3 fatty acids affect the electrophysiology of the
more » ... rt. Objective: To investigate the effect of supplemental intake of n-3 fatty acids on autonomic regulation and electrophysiology of the heart in apparently healthy subjects aged 50 to 70. Materials and methods: After a m-in period of 4 weeks, 84 subjects were randomized to receive capsules with either 3.5 g fish oil or placebo oil daily for 12 weeks. Before and after intervention, ECGs and blood pressure were recorded for 10 minutes with standardized respiration of 15 breaths per minute. Results: HRV and BRS did not significantly improve by the intake of n-3 fatty acids. HRV decreased by 3.05 ms or 7.7% (95% coniidence interval, -8.91 to 2.82 ms) and BRS decreased by 0.92 ms/mmHg or 0.1% (95% cmiidence interval, -2.66 to 0.81 ms/mmHg) in the fish oil group compared to the placebo group. ECG characteristics were hardly affected by n-3 fatty acids. Conclusions: N-3 fatty acids have no substantial effect on indicators of autonomic regulation in healthy subjects. Also, these results cm not support the hypothesis that n-3 fatty acids prevent arrhythmia through electrophysiologic effects on heart cell membranes. Potential effects of n-3 fatty acids on autonomic regulation and electrophysiology of the heart should be studied in more susceptible populations. Fast Fourier Transform (FFTJ algorithm is widely used in standard estimation of heart rate variability (HRV spectral indices, however, it seems to have some limitations. The goal of this work was to show how these limitations could influence final results of spectral analysis. Method: The stationary sinusoidal signals of T=120,300,600 s and various frequencies were numerically prepared. Calculations of FFT and exact Direct Fourier Transform (DFTJ were performed and then obtained power spectra were compared. Real samples of HRV data of length T=100,200,500 s were used in DFT calculations with frequency interval of l,T (= FFT), l/ZT, 1/5T, l/lOT, l/lOOT. Resulting power spectra were compared. Results: Power spectrum obtained by FFT, its peak power (up to 60% error) and peak frequency depend strongly on difference between signal frequency and nearest FFT frequency, while DFT algorithm with frequency resolution gives correct peak values around 5-10 times better than FFT. The results are consistent with theoretical predictions. This effect does not depend on duration of signal. Total power (TP) obtained by FFT changes about 5.10% depending on signal frequency, while DFT gives < 1%. Conclusions: Spectral parameters' values obtained by FFT algorithm can show up to 10% unpredictable errors of order. Application of DFT algorithm with better frequency resolution gives more stable and repetitive values of parameters. The results are of importance for analysis of heart rate variability spectral parameters. Aim of study: Influence of surgical reparation (SR) of second type atria1 septal defect (ASD II) on heart rate variability (HRV in children Study population: We observed 53 children, 32 girls and 21 boys, aged 0,s to 16,4 years (mean 6,76 years) with second type atria1 septal defect (ASD II) -group I and 38 children, 21 girls and 17 boys aged 0,s to 15,2 years (mean 7,86 years) without any cardiac disorder-group II. Methods: All pts with ASD II underwent 24.hour ECG Halter monitoring before, 1 month and 2 years after SR. Healthy children had 24.ECG recorded at the beginning of study. Based on 24.hour ECG recording the following HRV parameters were assessed: SDNN, rmsSD, pNN50, InTP, InLF, InHF and LF/HF ratio. Measured HRV parameters were analysed in children with ASD II before SR and within 2.years follow-up and compared to the healthy PWSOIK
doi:10.1016/s1099-5129(03)91955-6 fatcat:myajxgcoyzabvhiie27i3vsf3a