Heart Rate Variability as a Tell-Tale Marker of Pain-Related Autonomic Dysfunction in Chronic Pancreatitis

INTRODUCTION: Chronic pain causes an imbalance of autonomic function, often indicated by reductions in parasympathetic heart rate variability (HRV) indices. This study aimed to investigate HRV measures among patients with chronic pancreatitis (CP), and healthy controls (HCs), and the influence of diabetes on these parameters. METHODS: HRV measures, which are time- and frequency-derived noninvasive measures of autonomic function, were obtained from the electrocardiography (ECG) recordings. Moreover, deceleration capacity and periodic repolarization dynamics were assessed as measures of parasympathetic and sympathetic activity. RESULTS: A total of 141 participants (38 pain-free CP, 53 painful CP, and 50 healthy controls) were analyzed. Painful CP patients exhibited more pronounced parasympathetic reductions assessed with the root mean square of successive differences between normal beats (14.5 ms, IQR: 11.5-22 vs. 21.8 ms, IQR: 17.6-32.4; P =0.01) and high-frequency content (118.2 ms 2 vs. 273.4 ms 2 ; P =0.007) in comparison to pain-free CP. Moreover, there was a decreased standard deviation of normal-to-normal interbeat intervals (31.6±18.7 ms vs. 39.9±18.5 ms; P =0.04) and low-frequency content (158.9 ms 2 vs. 480.4 ms 2 ; P =0.003), indicating altered sympathovagal balance. Furthermore, the mean RR interval was greater in nondiabetic CP patients (830.5±144.2 ms) compared with those with diabetes (770.7±139.4 ms; P =0.05). CONCLUSIONS: Chronic pancreatitis, particularly when painful, is associated with significant autonomic dysregulation, characterized by a pronounced reduction in parasympathetic activity as measured by HRV compared with pain-free patients.