Key result
Pediatric syncope patients show similar orthostatic tolerance to controls despite impaired cardiovascular and autoregulatory responses.
Why the study?
Children and adolescents commonly experience orthostatic intolerance with impaired participation and quality of life, but their autonomic responses to presyncope are not well characterized compared to adults.
Do autonomic responses to provoked presyncope differ in children with recurrent presyncope/syncope compared to healthy adolescents?
Case-Control (n=53)
Do autonomic responses to provoked presyncope differ in children with recurrent presyncope/syncope compared to healthy adolescents?
Absolute Event Rate: 21% vs 20%
p-value: p=0.74
Children and adolescents have distinct, smaller sympathetically-mediated autonomic responses compared to adults, highlighting the need for pediatric-specific standards in evaluating orthostatic syncope.
Orthostatic tolerance time may underestimate autonomic impairment in pediatric syncope; leaves open whether targeted testing improves risk stratification.
Children and adolescents commonly experience orthostatic intolerance associated with impaired participation and quality of life. We aimed to characterize autonomic responses to provoked presyncope in children with recurrent presyncope/syncope and healthy adolescents. We determined orthostatic tolerance (OT, time to presyncope [mins]) in 36 pediatric patients (age 15 ± 3 yrs., 26 female) with recurrent presyncope/syncope, and 17 asymptomatic controls (age 13 ± 3 yrs., 8 female), using a tilt test with graded lower body negative pressure. Cardiovascular parameters, forearm vascular resistance (FVR), mean middle cerebral artery velocity (MCAv mean ), and breath-by-breath end tidal gases were continuously monitored. Responses to the Valsalva maneuver (VM), cerebral autoregulation, and cerebral reactivity to carbon dioxide were also determined. OT was similar in pediatric patients (21 ± 1.5 min) and controls (20 ± 2.0 min, p = 0.74), but smaller than adult reference values (33.8 ± 0.8 min, p < 0.01). Tilting decreased systolic arterial pressure in pediatric patients ( p = 0.009), but not pediatric controls ( p = 0.12). Tilting decreased MCAv mean ( p = 0.002) in pediatric patients, with impairments in cerebral autoregulation ( p = 0.02) that were negatively correlated with OT ( r = −0.322; p = 0.024). Both pediatric patients (+48.9 ± 8.0 %) and controls (+36.7 ± 14.7 %) had small FVR responses compared to adult reference data (+100 ± 12 %, p < 0.01). Blood pressure responses to the VM were abnormal in pediatric patients, with a lower nadir in mean arterial pressure (81.7 ± 2.0 mmHg) compared to pediatric controls (94.0 ± 2.8 mmHg, p = 0.001). Pediatric patients with recurrent presyncope/syncope had impaired orthostatic cardiovascular and autoregulatory responses compared to pediatric controls. Sympathetically-mediated responses were small in children, underscoring the need for pediatric-specific standards for orthostatic cardiovascular control, and treatments targeting enhancement of vascular resistance in children with syncope.
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Lucci et al. (2025) conducted a case-control in Recurrent presyncope/syncope (n=53). Recurrent presyncope/syncope vs. Healthy asymptomatic controls was evaluated on Orthostatic tolerance (time to presyncope in minutes) (p=0.74). Pediatric patients with recurrent presyncope/syncope had similar orthostatic tolerance to healthy controls (21 vs 20 min, p=0.74) but impaired cardiovascular and autoregulatory responses.
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