Autonomic dysfunction seems to play a central role in the pathophysiology of neurocardiogenic syncope (NCS) but conflicting data have recently become available. We evaluated autonomic nervous system (ANS) function (heart rate variability (HRV), systolic blood pressure variability (SBPV) and baroreceptor gain (BRG)) and non-invasive haemodynamics (cardiac output and total peripheral resistance) in patients with neurocardiogenic syncope. Retrospectively, we evaluated 12 NCS patients (positive head-up tilt without pharmacological provocation) in the basal state and at initial tilt, 12 non-NCS patients with tilt-negative syncope and 12 aged-matched normal controls. Prospectively, we evaluated 16 NCS patients to analyse the haemodynamics and ANS activity throughout the tilt test (beginning of tilt and before syncope occurs). HRV and SBPV were accessed by fast Fourier transforms (FFT) and spontaneous BRG by temporal sequences, slope and a index. Modelflow was used to quantify the non-invasive haemodynamics. None of the autonomic and haemodynamic parameters at baseline or in the first 10 min of tilt was different among the respective NCS, non-NCS syncope and normal control groups, except for SBP, which was higher at baseline in controls. Throughout the tilt test in the prospective NCS group, the heart rate increased (88-95 beats x min(-1), P<0.05), systolic blood pressure decreased (123-109 mmHg, P<0.01), and arterial baroreceptor gain was reduced (7.6 to 5.5 ms mmHg(-1), P<0.01) and the absolute high frequency component of HRV (HF HRV) decreased (150-80 ms(-2), P<0.05), before syncope occurred. There was no change in the low frequency component of HRV (LF HRV), SBPV, cardiac output (CO) or total peripheral resistance (TPR). Tilt-induced syncope could not be predicted by non-invasive haemodynamic or autonomic parameters at rest or in the initial minutes of tilt. The decrease in arterial baroreceptor gain could be a precocious expression of the transient autonomic dysfunction that characterizes the occurrence of neurocardiogenic syncope.

Objective: To examine the feasibility of a trial allocating different blood pressure (BP) intervention levels for treatment in extremely preterm infants. Design:Three-arm open randomised controlled trial performed between February 2013, and April 2015.Setting: Single tertiary level neonatal intensive care unit.Patients: Infants born <29weeks gestation were eligible to participate, if parents consented and they did not have a major congenital malformation.Interventions: Infants were randomised to different levels of mean arterial BP at which they received cardiovascular support: Active (<30mmHg), Moderate (

Objective This study aimed to compare left ventricular outflow tract (LVOT) diameter measurements using two-dimensional (2D) echocardiography at the sino-tubular junction (STJ) and at the aortic valve (AV) hinges in newborn infants. Study Design This is a retrospective study in a tertiary neonatal unit where infants underwent echocardiography for evaluation of murmur or as part of cardiovascular assessment. Three consecutive cardiac cycles were chosen to measure the LVOT diameter in end systole at the STJ and at the AV hinges. Bias and levels of agreement were examined using Bland–Altman plot. Intraobserver variability was examined using intraclass correlation. Results A total of 366 measurements were obtained from 61 infants with a mean (standard deviation) gestation and birth weight of 33.4 (6.9) weeks and 2,181 (1369) g, respectively. There was good correlation between the LVOT diameter measurements using the STJ and AV hinges (r = 0.958, p < 0.001). The mean (standard deviation and 95% confidence interval) bias between LVOT diameter measurements using STJ and AV hinges were 0.93 (0.45 and 0.06–1.81) mm. There was good intraobserver variability between the measurements using both methods. Conclusion Using 2D echocardiography, LVOT measurements using the STJ tend to be higher when compared with LVOT measurements using the AV hinges. Key Points