Improvements in Heart Rate Variability in Women with Obesity: Short-term Effects of Sleeve Gastrectomy

Purpose Obesity has been associated with reduced vagal function and increased sympathetic activity. Cardiac autonomic dysfunction has emerged as a major risk factor in the development of cardiovascular disease. Cardiac autonomic function (CAF) can be assessed by heart rate variability (HRV), an independent predictor of mortality based on changes in time intervals between adjacent heartbeats (RR). Bariatric surgery is considered the most effective treatment for obesity and its comorbidities, with sleeve gastrectomy (SG) being the most frequent bariatric procedure. There are few studies on HRV changes in women with obesity after SG. The aim of this study was to evaluate the short-term impact of SG on CAF and its relationship with weight loss. Materials and Methods An observational cohort study was conducted. Twenty-three female patients were assessed before SG and at 1 and 3 months after surgery. CAF was evaluated by analyzing HRV from 5-min records of RR intervals while the subject was supine. HRV was analyzed in time and frequency domains and with a nonlinear method. Results Patients (36.0 +/- 11.1 years old, BMI 35.1 +/- 3.4 kg/m(2)) presented higher HRV values, on average, in all domains both at 1 and 3 months after SG (p < 0.05). In addition, all anthropometric parameters improved (p < 0.001) although there was no relationship between HRV improvements and anthropometric changes. Conclusion SG seems to be effective at reducing excess weight and improving HRV at the short term, and these changes are detectable as early as the first month after surgery. HRV assessment appears as a promising low-cost tool that deserves further research.