Can heart rate variability be utilised to predict compensatory sweating after endoscopic thoracic sympathicotomy in patients with primary focal hyperhidrosis?

Introduction/Objective. Hyperhidrosis is a condition of pathological excessive sweating that exceeds the body’s physiological requirements for thermoregulation. Endoscopic thoracic sympathicotomy (ETS) is a commonly used treatment for primary focal hyperhidrosis (PFH); however, it may result in compensatory sweating (CS), which represents its most frequent postoperative complication. This study aimed to investigate whether heart rate variability (HRV) parameters could predict CS. Methods. A prospective single-center study was conducted in 100 patients with primary focal hyperhidrosis (PFH) who underwent ETS. Preoperatively, all patients underwent 24-hour Holter ECG monitoring to assess standard HRV parameters. ETS was performed by transection of the sympathetic chain at the level of the third (R3) and fourth rib (R4), including the accessory Kuntz fibers. One month after surgery, the presence and severity of CS were assessed. Results. CS was absent in 61% of patients (p=0.028). Mild CS was the most common form (p < 0.01). No statistically significant differences were observed in the analyzed preoperative HRV parameters between patients with and without CS (p > 0.05), including the low-frequency (LF)/high-frequency (HF) ratios, which represent balanced autonomic activity (LF/HF < 2) and sympathetic predominance (LF/HF ≥ 2). ROC curve analysis showed that age had significant predictive accuracy for CS (AUC 0.7333; 95% CI 0.634-0.833; p < 0.01), with an optimal cutoff of 23.5 years (sensitivity 0.82, specificity 0.47). Conclusion. HRV parameters cannot reliably predict CS following bilateral ETC in patients with PFH. The study confirmed that the optimal age for surgery is below 23.5 years.