Heart rate variability as measurement of heart-brain interactions

Autonomic mediated heart-brain interactions are implicated in the regulation of different physiological and pathological situations. They reflect the influence of parasympathetic and sympathetic systems over the cardiac activity. In past years, a considerable number of methodological approaches applied to non-invasive electrocardiogram (ECG) recordings have been developed for the assessment of autonomic function. They are based on quantitative analyses of the heart rate variability (HRV), which, through different measurements in time and frequency domains or through non-linear estimations, have revealed useful information in diverse clinical contexts. In the present article, we provide a review of the general aspects related to the analysis of HRV including a brief summary of the physiological bases and methodological approaches together with some reported applications.