Autonomic control of heart period in duodenal ulcer patients - Insights from spectral analysis of heart rate variability

Beyond the fundamental pathogenetic importance of Helicobacter Pylori a pos sible additional role of vagal innervation in favouring or modulating the c linical history of duodenal ulcer (DU) has been suggested by old studies em ploying invasive methodologies. Aim of this study was to assess whether vag al prevalence in autonomic modulation was present in healed DU patients (n= 20) as compared to controls,(n=50), using a validated non-invasive methodol ogy, based on spectral analysisis of cardiovascular variability. This appro ach provides markers of the sympathetic and vagal modulations of the SA nod e, respectively by way of the normalized low frequency (LFRR) and high freq uency (HFRR) components of RR interval variability; LF/HF ratio furnishes a marker of sympatho-vagal balance. In addition, sham feeding (SF) provided a means to assess, in DU patients, neurally mediated acid secretion, as the SF acid output (SAO) to basal acid output (BAO) ratio (SAO/BAO). Results s howed that LFRR was smaller in DU patients than in controls (40.3+/-3.9 vs. 52.3+/-2.3 normalized units, nu; P<0.05). On the contrary, HFRR was greate r (52.1+/-3.7 vs. 35.7+/-2.3 nu; P<0.05). Conversely the LF component of SA P variability, a marker of sympathetic vasomotor modulations, and the index alpha, a measure of barorefIex control of the SA node, as well as respirat ory patterns, were similar in the two groups. SAO/BAO ratio was significant ly correlated with markers of autonomic control of the SA node (r=-0.67, P< 0.0083 with HFRR). In conclusion results suggest an enhanced vagal modulati on of heart period in DU patients at rest, that appears Linked to indices o f neurally mediated gastric acid secretion response. (C) 2000 Elsevier Scie nce B.V. All rights reserved.