SPECTRAL-ANALYSIS OF HEART-RATE-VARIABILITY IN PATIENTS WITH IRRITABLE-BOWEL-SYNDROME

Background: Autonomic dysfunction, both adrenergic and cholinergic, ha s been associated with the irritable bowel syndrome (IBS). The accurac y of the methods in use, however, has been limited by the need for act ive co-operation by the patients, with consequent difficulties in stan dardization. The aim of this study was to investigate the function of the autonomic nervous system in patients with IBS by using spectral an alysis of the heart rate variability, an accurate method depending ver y little on patient cooperation. Methods: Eighteen patients with IBS w ere compared with 36 sex-and age-matched controls. Spectral analysis o f heart rate variability was performed to quantify sympathetic and par asympathetic nerve activity. Results: The patients with IBS had signif icantly higher sympathetic activity than controls (P=0.005). There was no significant (P=0.308) increase in parasympathetic activity. There were no significant differences in heart rate or blood pressure betwee n the patients and controls. Conclusion: Spectral analysis of heart ra te variability has been used to assess the function of the autonomic n ervous system in patients with IBS. IBS patients have significantly in creased symphathetic activity, whereas parasympathetic activity does n ot differ from that of controls.