Key result
Pediatric vasovagal syncope is linked to ~30% lower 24-hour SDANN, signaling increased sympathetic tone.
Why the study?
Abnormalities of the autonomic nervous system in children and adolescents with vasovagal syncope were not well characterized.
Are there abnormalities in heart rate variability in pediatric patients with vasovagal syncope compared to healthy volunteers?
Case-Control (n=97)
Are there abnormalities in heart rate variability in pediatric patients with vasovagal syncope compared to healthy volunteers?
Absolute Event Rate: 256.21% vs 366.51%
p-value: p=0.048
Pediatric patients with vasovagal syncope exhibit altered basal autonomic balance characterized by increased sympathetic modulation, which is more pronounced in adolescent males.
Does not support routine HRV monitoring in pediatric syncope; leaves open whether reduced SDANN predicts outcomes or guides therapy.
Introduction The aim of the study was to detect any abnormalities of the autonomic nervous system in children and adolescents with vasovagal syncope. Material and methods We studied 56 children, ages eight to 17 years, with a history of vasovagal syncope and 41 healthy volunteers. Heart rate variability was calculated over a 24-hour period for heart rate, standard deviations of the averages of the R-R intervals in all 5-min segments of R-R intervals (SDANN), the root of the 24-hour square (RMSSD), the proportion of adjacent normal R-R intervals < 50 ms (pNN50), the total power (TP), the low frequency index (LF), the high frequency index (HF), and the LF/HF ratio. Results Patients with vasovagal syncope had significantly reduced values of 24-hour (256.21 ±190.97 ms, 366.51 ±264.7 ms, p = 0.048) and night-time SDANN (168.56 ±140.59 ms, 251.54 ±189.92 ms, p = 0.034); 24-hour (292.96 ±226.25 ms, 390.49 ±254.06 ms, p = 0.046), daytime (349.52 ±298.32 ms, 479.23 ±350.39 ms, p = 0.040), and night-time RMSSD (188.47 ±161.07 ms, 271.05 ±200.70 ms, p = 0.029); daytime pNN50 (25.10 ±13.10%, 32.10 ±14.19%, p = 0.037); and increased value of night-time LF/HF ratio (1.43 ±1.50, 0.86 ±1.00, p = 0.015), in comparison to healthy subjects. In adolescents with vasovagal syncope we found significantly lower values of 24-hour (7578.29 ±5409.74 ms2, 12236.00 ±5651.45 ms2, p = 0.025) and daytime TP (4776.19 ±4146.56 ms2, 10488.70 ±8326.43 ms2, p = 0.039), 24-hour (2120.90 ±2057.00 ms2, 3634.22 ±3026.90 ms2, p = 0.015) and daytime HF (930.10 ±1101.66 ms2, 7832.90 ±18825.10 ms2, p = 0.015), in comparison with children. Males presented lower values of 24-hour (207.4 ±134.63 ms, 324.00 ±236.95 ms, p = 0.042) and daytime SDANN (264.56 ±208.16 ms, 432.65 ±320.52 ms, p = 0.044), and daytime RMSSD (282.54 ±248.94 ms, 446.28 ±342.35 ms, p = 0.041) compared with females. Conclusions Paediatric patients with vasovagal syncope had alterations in basal autonomic balance, which indicated an increased sympathetic modulation. More severe autonomic imbalance occurs in adolescent males.
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Kovalchuk et al. (2019) conducted a case-control in Vasovagal syncope (n=97). Vasovagal syncope vs. Healthy volunteers was evaluated on 24-hour SDANN (standard deviations of the averages of the R-R intervals) (p=0.048). Pediatric patients with vasovagal syncope had significantly reduced 24-hour SDANN (256.21 vs 366.51 ms, p=0.048) compared to healthy controls, indicating an increased sympathetic modulation.
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