No abstract

The observed associations between reduced circulating androgens, oestrogens and lower HRV and depleted BRS, irrespectively of HF severity suggest the pathophysiological links between these two mechanisms. These results constitute the premises to investigate whether the pharmacological supplementation of depleted hormones would enable to restore the autonomic balance and improve the efficacy of reflex control within the cardiovascular system in men with systolic HF.

In patients suffering from heart failure (HF), autonomic imbalance develops even at early stages along with derangements of cardiopulmonary reflex control and abnormalities in metabolism of several hormones. In 34 men with stable systolic HF, we investigated hypercapnic chemosensitivity (HCS, liter/min•mm Hg) measured using the rebreathing method and defined as the slope of the regression line relating minute ventilation (VE, liter/min) to endtidal carbon dioxide concentration (PETCO 2 , mm Hg). Serum levels of testosterone, dehydroepiandrosterone sulfate, type1 insulinlike growth factor (IGF1), sex hormone binding globulin (SHBG), estradiol, and cortisol were measured using immunoassays. We found that there were no associations between HCS and clinical variables, applied therapy, and comorbidities (all P > 0.2). Augmented HCS was accompanied by increased serum SHBG (when expressed in nM, r = 0.43, P < 0.05; when expressed as percentage of the age matched reference values, r = 0.62, P < 0.001) and the reduced serum IGF1 (when expressed in ng/ml and as percentage of the abovementioned values, r = -0.49, P < 0.05, and r = = -0.47, P = 0.007, respectively). The HCS was not related to serum levels of all the remaining analyzed hormones (all P > 0.2). Thus, it may be suggested that the hormone stimuli can noticeably modify the reflex mechanisms in cardiorespiratory control in the clinical setting of cardiovascular pathology.