This study assessed the exercise tolerance and the cardiorespiratory responses to a training program by the six-minute walk test (6'WT) in children with congenital heart disease (CHD). Seventeen cardiac and 14 healthy children performed maximal cardiopulmonary exercise test (CPET) and 6'WT. Reliability of 6'WT was assessed in all subjects (test-retest) by Bland-Altman plots. Cardiac subjects were randomly divided in training (T-CHD) and control groups (C-CHD). T-CHD underwent an individualized training exercise at the ventilatory threshold (VT) intensity during 12 weeks. We found that the 6'WT is a reliable and reproducible test. CHD children walked a lower distance than healthy children before training (472.5 +/- 18.1 vs. 548.8 +/- 7.7 m, respectively, p < 0.001). Likewise, power output, oxygen uptake (V.O (2)), and heart rate (HR) at the maximum and the VT levels, were significantly lower in patients (p < 0.001). After training, a significant improvement of walking distance (WD) was shown in T-CHD (529.6 +/- 15.3 vs. 467.7 +/- 17.1 m, p < 0.001). The power output, VO2, HR, and V.E increased slightly (6 to 10 %, p > 0.05) at peak exercise and significantly at ventilatory threshold level (p < 0.05) in T-CHD. Significant relationships between WD and VO2max as well as VO2 at VT were founded (p < 0.05). We concluded that the 6'WT is a useful and reliable tool in the assessment and follow-up of functional capacity during rehabilitation program in children with CHD.

We investigated the effect of training on peripheral muscular performance and oxygenation during exercise and recovery in children with congenital heart diseases (CHD). Eighteen patients with CHD aged 12 to 15 years were randomly assigned into either an individualized 12-week aerobic cycling training group (TG) or a control group (CG). Maximal voluntary contraction (MVC) and endurance at 50% MVC (time to exhaustion, T(lim)) of the knee extensors were measured before and after training. During the 50% MVC exercise and recovery, near-infrared spectroscopy (NIRS) was used to assess the fall in muscle oxygenation, i.e., deoxygenation ([Formula: see text]) of the vastus lateralis, the mean rate of decrease in muscle oxygenation, the half time of recovery (T(1/2R)), and the recovery speed to maximal oxygenation (R(S)). There was no effect of time on any parameter in the CG. After training, significant improvements were observed in TG for MVC (101.6 ± 14.0 vs. 120.2 ± 19.4 N·m, p < 0.01) and T(lim) (66.2 ± 22.6 vs. 86.0 ± 23.0 s, p< 0.01). Increased oxygenation (0.20 ± 0.13 vs. 0.15 ± 0.07 a.u., p < 0.01) and faster mean rate of decrease in muscle oxygenation were also shown after training in TG (1.22 ± 0.45 vs. 1.71 ± 0.78%·s(-1), p < 0.001). Moreover, a shorter recovery time was observed in TG after training for T(1/2R) (27.2 ± 6.1 vs. 20.8 ± 4.2 s, p < 0.01) and R(S) (63.1 ± 18.4 vs. 50.3 ± 11.4 s, p < 0.01). A significant relationship between the change in [Formula: see text] and both MVC (r = 0.95, p < 0.001) and T(lim) (r = 0.90, p < 0.001) in TG was observed. We concluded that exercise training improves peripheral muscular function by enhancing strength and endurance performance in children with CHD. This improvement was associated with increased oxygenation of peripheral muscles and faster recovery.

Persistent pulmonary hypertension of the newborn (PPHN) occurs in 1-4% of neonates with transposition of the great arteries with intact ventricular septum (TGA/IVS). This association is often lethal. To our knowledge, only eight survivors have been described in the literature, two of whom benefited from extracorporeal membrane oxygenation (ECMO). We report two cases of PPHN complicating a TGA/IVS that were refractory to multiple therapies and resolved 48 hours after initiation of bosentan therapy. Bosentan, an oral dual endothelin-1 receptor antagonist, is a new treatment for pulmonary arterial hypertension that was both effective and safe in these two cases of TGA/IVS with PPHN. To our knowledge, it is the first use of bosentan in newborns.

Abstract-Ultrasound images segmentation is a difficult problem due to speckle noise, low contrast and local changes of intensity. Intensity based methods do not perform particularly well on ultrasound images. However, it has been previously shown that these images respond well to local phase-based methods which are theoretically intensity-invariant. Here, we use level set propagation to capture the left ventricle boundaries. This uses a new speed term based on local phase and local orientation derived from the monogenic signal, which makes the algorithm robust to attenuation artefact. Furthermore, we use Cauchy kernels, instead of the commonly used log-Gabor, as pair of quadrature filters for the feature extraction. Preliminary results show that the proposed method can robustly handle noise, and captures well the low contrast boundaries.

Abstract-Ultrasound images segmentation is a difficult problem due to speckle noise, low contrast and local changes of intensity. Intensity based methods do not perform particularly well on ultrasound images. However, it has been previously shown that these images respond well to local phase-based methods which are theoretically intensity-invariant. Here, we use level set propagation to capture the left ventricle boundaries. This uses a new speed term based on local phase and local orientation derived from the monogenic signal, which makes the algorithm robust to attenuation artefact. Furthermore, we use Cauchy kernels, instead of the commonly used log-Gabor, as pair of quadrature filters for the feature extraction. Preliminary results show that the proposed method can robustly handle noise, and captures well the low contrast boundaries.