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Reliable and effective noninvasive measures of sympathetic and parasympathetic peripheral outflow are of crucial importance in cardiovascular physiology. Although many techniques have been proposed to take up this long-lasting challenge, none has proposed a satisfying discrimination of the dynamics of the two separate branches. Spectral analysis of heart rate variability is the most currently used technique for such assessment. Despite its widespread use, it has been demonstrated that the subdivision in the low-frequency (LF) and high-frequency (HF) bands does not fully reflect separate influences of the sympathetic and parasympathetic branches, respectively, mainly due to their simultaneous action in the LF. Two novel heartbeat-derived autonomic measures, the sympathetic activity index (SAI) and parasympathetic activity index (PAI), are proposed to separately assess the time-varying autonomic nervous system synergic functions. Their efficacy is validated in landmark autonomic maneuvers generally employed in clinical settings. The novel measures move beyond the classical frequency domain paradigm through identification of a set of coefficients associated with a proper combination of Laguerre base functions. The resulting measures were compared with the traditional LF and HF power. A total of 236 ECG recordings were analyzed for validation, including autonomic outflow changes elicited by procedures of different nature and temporal variation, such as postural changes, lower body negative pressure, and handgrip tests. The proposed SAI-PAI measures consistently outperform traditional frequency-domain indexes in tracking expected instantaneous autonomic variations, both vagal and sympathetic, and may aid clinical decision making, showing reduced intersubject variability and physiologically plausible dynamics. NEW & NOTEWORTHY While it is possible to obtain reliable estimates of parasympathetic activity from the ECG, a satisfying method to disentangle the sympathetic component from HRV has not been proposed yet. To overcome this long-lasting limitation, we propose two novel HRV-based indexes, the sympathetic and parasympathetic activity indexes.

Background-Clinical trials in children with congenital heart disease are often limited by the absence of: 1) a primary outcome that can be observed in a reasonable period of time; 2) information regarding health-related quality of life; 3) knowledge of the correlation between health status and ventricular function and exercise performance; 4) a sufficient number of children at a single institution to provide adequate statistical power; and 5) procedural and management differences between and within institutions.

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Our data demonstrated that the antimicrobial lubricant prior biopsy leads to reduced bacterial load. Moreover, our data show the tendency for reduced ciprofloxacin-resistant bacteria growth when antimicrobial lubricant was instilled prior biopsy. However, the incidence of ciprofloxacin-resistant bacteria is low in our patient population. Rectal swabs should assess fluoroquinolone-resistance rates at prostate biopsy.