Differences and effects on heart rate variability regarding time-domain parameters and frontal QRS-T angle in irritable bowel syndrome with diarrhea or constipation

Aim: Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder associated with autonomic nervous system (ANS) abnormalities. The primary aim is to examine heart rate variability (HRV) in IBS patients and identify differences between diarrhea (IBS-D) and constipation-predominant (IBS-C) subtypes with time-domain (T-D) parameters linked to parasympathetic nervous system (PNS) activity using 24-hour Holter electrocardiography (ECG). The secondary aim is to determine if ANS dysregularities affect frontal QRS-T angle f(QRS-T) and ECG features.Material and Methods: The patients with palpitation symptoms who had a 24-hour Holter ECG evaluation at our clinic from January 2019 to December 2022 were reviewed retrospectively. Twenty-five patients with IBS-D, 25 with IBS-C, and 50 healthy controls were included.Results: According to univariate logistic regression, the PR interval, 24-hour minimum heart rate (minHR), rMMSSD, pNN50, and SDNN index are predictors of IBS. In multivariate logistic regression analysis, only the 24-Hour minHR and SDNN index remained significant as an independent predictor of IBS. Based on the Scatter-Plot, 12% of the variation in the 24-hour minHR was connected to the SDDN index. IBS had a moderate negative association with minHR and SDNN index, a weak negative correlation with rMMSSD and pNN50, and a weak positive correlation with PR interval. The IBS predictability of the PR interval, 24-Hour minHR, rMMSSD, pNN50, and SDNN index was also determined using ROC analysis.Discussion: We found that T-D parameters were adversely affected in IBS, irrespective of subtype. PR intervals were longer in IBS than controls; however, the f(QRS-T) angle did not differ between the subtypes.