Ng Clinton, Malcolm Allison, Hansen Ross, Kellow John
Gastrointestinal Investigation Unit, Department of Gastroenterology, Royal North Shore Hospital & University of Sydney, St Leonards, NSW 2065, Australia.
Scand J Gastroenterol. 2007 Apr;42(4):441-6. doi: 10.1080/00365520600965749.
Alterations in autonomic balance, detectable by heart rate variability (HRV) analysis, have been shown to occur after a meal in patients with irritable bowel syndrome (IBS). There are few data on changes in sympathovagal responses in IBS to other forms of enteric stimulation such as colonic distension. The aim of this study was to determine the effects of colonic balloon distension on HRV in the fasting and the postprandial state in healthy subjects and in IBS patients.
Eight IBS patients and 8 age- and gender-matched healthy subjects underwent unsedated descending colonic distension before and after a 1000 kcal liquid meal. Low- (LF) and high-frequency (HF) HRV band values obtained from 2-min ECG segments recorded before and during distension were compared between groups, and between fasting and postprandial states. A visual analogue scale was used to determine sensation during colonic distension.
HF values decreased significantly with feeding in IBS patients (p=0.01), but not in healthy subjects. The low-to-high frequency (LF/HF) ratio was significantly higher postprandially in IBS patients (p=0.02) and, additionally, was decreased (p<0.01) with colonic distension in the fed state, independently of colonic sensitivity or distending volume. Moreover, changes in the LF/HF ratio with distension in the fed versus the fasting state were negatively correlated in IBS patients but positively correlated in healthy subjects (both p<0.05).
IBS patients demonstrated altered autonomic responses to feeding and colonic distension. Further studies should determine whether these alterations could explain the postprandial exacerbation of symptoms in IBS.
通过心率变异性（HRV）分析可检测到，肠易激综合征（IBS）患者进食后会出现自主神经平衡改变。关于IBS患者对其他形式的肠道刺激（如结肠扩张）的交感迷走神经反应变化的数据较少。本研究的目的是确定结肠球囊扩张对健康受试者和IBS患者在空腹和餐后状态下HRV的影响。
8例IBS患者和8例年龄及性别匹配的健康受试者在摄入1000千卡流食前后接受了未镇静状态下的降结肠扩张。比较两组之间以及空腹和餐后状态下，扩张前和扩张期间记录的2分钟心电图片段获得的低频（LF）和高频（HF）HRV频段值。使用视觉模拟量表确定结肠扩张期间的感觉。
IBS患者进食后HF值显著下降（p = 0.01），而健康受试者则无此现象。IBS患者餐后低频与高频比值（LF/HF）显著更高（p = 0.02），此外，在进食状态下，结肠扩张使其降低（p<0.01），且与结肠敏感性或扩张体积无关。此外，IBS患者进食状态与空腹状态下LF/HF比值随扩张的变化呈负相关，而健康受试者则呈正相关（均p<0.05）。
IBS患者对进食和结肠扩张的自主神经反应发生改变。进一步研究应确定这些改变是否可以解释IBS患者餐后症状加重的原因。
