Strieper M J, Campbell R M
Children's Heart Center, Egleston Children's Hospital, Emory University, Atlanta, Georgia 30322.
J Am Coll Cardiol. 1993 Aug;22(2):594-7. doi: 10.1016/0735-1097(93)90070-h.
The purpose of our study was to determine whether alpha-adrenergic agonist therapy could prevent neurocardiogenic syncope in pediatric patients.
Recent reports from adult patients suggest that withdrawal of alpha-sympathetic stimulation contributes to neurocardiogenic syncope.
Sixteen young patients (mean age 13.1 years, range 7 years 10 months to 17 years 10 months) with recurrent syncope and a positive baseline head-up tilt response were studied. After a positive baseline tilt response, phenylephrine was infused and repeat tilt was performed for 30 min or until the test result was positive. At discharge, patients were followed up on a regimen of oral pseudoephedrine to evaluate treatment effectiveness and side effects.
During baseline tilt, seven patients experienced vasodepressor syncope, seven had mixed vasodepressor-cardioinhibitory syncope and two had cardioinhibitory responses. All patients became symptomatic, reproducing their clinical symptoms. Baseline mean arterial pressure decreased slightly immediately on tilt testing and significantly at the end point (82 +/- 13 vs. 77 +/- 18 vs. 30 +/- 14 mm Hg, respectively, p < 0.0001). Although heart rate varied, the changes were not statistically significant (78 +/- 17 vs. 105 +/- 19 vs. 87 +/- 46 beats/min, respectively, p = NS). Phenylephrine was infused (mean 1.74, range 0.6 to 3.0 micrograms/kg per min) as patients underwent follow-up tilt testing. Fifteen patients remained asymptomatic without hemodynamic changes; the remaining patient manifested a blunted mixed response. During phenylephrine infusion, heart rate (64 +/- 12 vs. 81 +/- 17 vs. 76 +/- 16 beats/min, respectively, p = NS) and mean arterial pressure (96 +/- 15 vs. 83 +/- 19 vs. 80 +/- 18 mm Hg, respectively, p = NS) did not change. During outpatient oral pseudoephedrine treatment (mean 11.7, range 6 to 14) 15 of 16 patients reported that their clinical condition was controlled without side effects.
Alpha-adrenergic stimulation prevents pediatric neurocardiogenic syncope. Intravenous phenylephrine prevents neurocardiogenic syncope during head-up tilt, despite reflex vagal bradycardia. Oral pseudoephedrine alleviates symptoms in patients with neurocardiogenic syncope without causing significant side effects.
我们研究的目的是确定α-肾上腺素能激动剂治疗能否预防小儿神经心源性晕厥。
来自成年患者的近期报告表明，α-交感神经刺激的撤除与神经心源性晕厥有关。
对16例复发性晕厥且基础直立倾斜试验反应阳性的年轻患者（平均年龄13.1岁，范围7岁10个月至17岁10个月）进行研究。在基础直立倾斜试验反应阳性后，输注去氧肾上腺素并再次进行倾斜试验30分钟或直至试验结果为阳性。出院时，对患者采用口服伪麻黄碱方案进行随访，以评估治疗效果和副作用。
在基础倾斜试验期间，7例患者发生血管抑制性晕厥，7例发生混合性血管抑制性-心脏抑制性晕厥，2例有心脏抑制性反应。所有患者均出现症状，重现其临床症状。基础平均动脉压在倾斜试验开始时立即略有下降，在试验终点时显著下降（分别为82±13 vs. 77±18 vs. 30±14 mmHg，p<0.0001）。尽管心率有所变化，但差异无统计学意义（分别为78±17 vs. 105±19 vs. 87±46次/分钟，p=无显著性差异）。在患者进行随访倾斜试验时输注去氧肾上腺素（平均1.74，范围0.6至3.0微克/千克每分钟）。15例患者无症状且血流动力学无变化；其余1例表现为反应减弱的混合性反应。在输注去氧肾上腺素期间，心率（分别为64±12 vs. 81±17 vs. 76±16次/分钟，p=无显著性差异）和平均动脉压（分别为96±15 vs. 83±19 vs. 80±18 mmHg，p=无显著性差异）未改变。在门诊口服伪麻黄碱治疗期间（平均11.7，范围6至14），16例患者中有15例报告其临床状况得到控制且无副作用。
α-肾上腺素能刺激可预防小儿神经心源性晕厥。静脉注射去氧肾上腺素可预防直立倾斜试验期间的神经心源性晕厥，尽管会出现反射性迷走神经性心动过缓。口服伪麻黄碱可缓解神经心源性晕厥患者的症状，且不会引起明显副作用。
