Autonomic cardiovascular regulation in quiescent ulcerative colitis and Crohn's disease

In inflammatory bowel diseases, changes in autonomic enteric regulation may also affect neural cardiovascular control. However, while cardiac autonomic modulation has been shown to be impaired in active ulcerative colitis, the occurrence of cardiovascular autonomic alterations, also in the quiescent phase of inflammatory bowel diseases, is still a matter of debate. The aim of our study was thus to explore the features of cardiovascular autonomic regulation in ulcerative colitis and Crohn's disease during their remission phase.

Autonomic cardiovascular control was evaluated by time- and frequency-domain indexes of spontaneous heart rate and blood pressure variability and by assessing the baroreflex heart rate control (sequence technique) in 26 patients with ulcerative colitis, in 26 patients with Crohn's disease and in 23 healthy controls.

The groups were matched for age, gender and body mass index. They had similar blood pressure mean levels and variability. By contrast, mean heart rate, its overall variability (standard deviation), and baroreflex sensitivity were lower in ulcerative colitis patients than in controls. Moreover, all indexes related to cardiac vagal control were significantly lower in ulcerative colitis patients with respect not only to controls but also to Crohn's disease patients.

Cardiac vagal control is impaired in quiescent ulcerative colitis only, and not in Crohn's disease, while in both bowel diseases vascular control appears preserved. Since cardiovagal modulation seems related to anti-inflammatory mechanisms, the reduced parasympathetic cardiac regulation in apparently quiescent ulcerative colitis suggests that such systemic derangement is accompanied by local subclinical inflammations, even in the absence of clinically active inflammatory processes.