Obesity and heart rate variability in men with myocardial infarction.

BACKGROUND Obesity has been shown to affect heart rate variability (HRV). Adipokines (hormone-like peptides secreted by adipose tissue) display several bioactivities and have an impact on the cardiovascular system. The aim of the study was to evaluate the impact of obesity (BMI > or = 30) and adipokines (leptin, adiponectin and resistin) on HRV. METHODS In 43 obese and 38 non-obese males with acute myocardial infarction, plasma adipokines were determined. 24-hour Holter ECG with time and frequency domain HRV analysis was performed. RESULTS Anthropometric measurements, leptin and resistin were significantly higher and adiponectin was lower in the obese than in the non-obese group. SDNN, SDANN, SDNN-i, rMSSD, p-NN50 and HF were reduced in obese patients, whereas LF/HF was higher. Waist circumference was a better correlate of HRV parameters than body mass index. Several associations between HRV parameters and adipokines were observed: between SDNN and leptin (r = -0.32; p < 0.001) and resistin (r = -0.26; p < 0.05); SDANN and leptin (r = -0.26; p < 0.05) and resistin (r = -0.29; p < 0.001); SDNN-i and resistin (r = -0.40; p < 0.001); LF and leptin (r = 0.22; p < 0.05); HF and resistin (r = -0.22; p < 0.05); LF/HF and leptin (r = 0.46; p < 0.001) and resistin (r = 0.44; p < 0.001). CONCLUSIONS Obesity is related to sympathovagal imbalance characterized by depressed parasympathetic tone and increased sympathetic activity. The relation between blood leptin and resistin concentration to the HRV parameters may indicate a possible link between adipokines and disturbances of the autonomic nervous system.