Autonomic cardiovascular responses are impaired in women with irritable bowel syndrome.
OBJECTIVE
This study characterizes cardiovascular autonomic function in women with irritable bowel syndrome (IBS), using standardized techniques.


BACKGROUND
Autonomic dysfunction is believed to contribute to abnormal gastrointestinal motility and visceral hypersensitivity in IBS. There is mounting evidence of generalized impairment of autonomic activity in patients with IBS.


METHODS
Thirty women aged 39 years (95% C.I. 25-53 years) diagnosed with IBS, and 30 age-matched healthy women were studied. The ratio of low frequency to high frequency heart rate variability domains (LF:HF ratio) was used to represent cardiac sympathovagal activity, and orthostatic testing and sustained isometric handgrip exercise were used as sympathetic stimuli. Parasympathetic activity was represented by the expiratory to inspiratory R-R interval (E:I) ratio during deep breathing at 6 minutes.


RESULTS
LF:HF responses to handgrip exercise (316%, C.I. 134% to 498% vs. 107%, C.I. 15% to 153%; P < 0.05) and orthostatic testing (648%, C.I. 520% to 904% vs. 330%, C.I. 140% to 520%; P < 0.05) were higher in IBS patients than controls, and the E:I ratio was significantly lower (1.47, C.I. 1.33-1.61 vs. 1.20, C.I. 1.14-1.26; P < 0.01).


CONCLUSIONS
Autonomic cardiovascular function is impaired in IBS, manifest as attenuated cardio-vagal tone, and relative sympathetic excess during stimulated conditions.
Clinical Pharmacology Unit and Research Centre, University of Edinburgh. s.waring@ed.ac.uk
W Stephen
WS
Waring
Michelle
M
Chui
Alan
A
Japp
E Fiona
EF
Nicol
Mike J
MJ
Ford
D000293:Adolescent; D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002319:Cardiovascular System / Q000503:physiopathology*; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000503:physiopathology*; D008875:Middle Aged