Evolving electroanatomic substrate and intra-atrial reentrant tachycardia late after Fontan surgery

Atrial Remodeling After the Fontan Operation. Introduction: The prevalence of intra‐atrial reentrant tachycardia (IART) increases with age in Fontan patients. This study aimed to characterize the atrial electroanatomic substrate for IART late after Fontan surgery. Methods and Results: Detailed electroanatomic mapping of the right atrium (RA) was performed in 11 consecutive patients (33 ± 9 years) with older style Fontan circulation (atriopulmonary and atrioventricular connection) who underwent their first radiofrequency catheter ablation (RFCA) for IART. A comparative group of 30 non‐Fontan congenital heart disease (CHD) patients were also studied. Fontan patients had larger RA (P = 0.004), larger low‐voltage area ≤0.5 mV (P = 0.01), and more fractionated potentials (P < 0.001) than non‐Fontan CHD patients. RA enlargement correlated significantly with both low‐voltage zones (Spearman ρ= 0.68, P < 0.001) and fractionated potentials (Spearman ρ= 0.48, P = 0.001). Among Fontan patients, both age and time since Fontan surgery were significantly correlated to the amount of low‐voltage areas (Spearman ρ= 0.87, P < 0.001; Spearman ρ= 0.63, P = 0.04, respectively). Successful RFCA was accomplished in 30 (73%) patients and was less likely in Fontan patients (54% vs 83%, P = 0.04). Larger RA was significantly associated with a lower success rate (P = 0.04). During a follow‐up duration of 2.3 ± 1.6 years, IART recurred in 47% of patients. Larger RA size and larger low‐voltage areas predicted IART recurrence after RFCA. Conclusion: Fontan patients demonstrate progressive adverse atrial electrical remodeling with increasing age and time since surgery. Newer strategies beyond surgical incisions, such as pharmacotherapies that retard the progression of atrial fibrosis, may be required to reduce the long‐term risk of atrial arrhythmias.     

Increased cortical porosity in type 2 diabetic postmenopausal women with fragility fractures

The primary goal of this study was to assess peripheral bone microarchitecture and strength in postmenopausal women with type 2 diabetes with fragility fractures (DMFx) and to compare them with postmenopausal women with type 2 diabetics without fractures (DM). Secondary goals were to assess differences in nondiabetic postmenopausal women with fragility fractures (Fx) and nondiabetic postmenopausal women without fragility fractures (Co), and in DM and Co women. Eighty women (mean age 61.3 ± 5.7 years) were recruited into these four groups (DMFx, DM, Fx, and Co; n = 20 per group). Participants underwent dual‐energy X‐ray absorptiometry (DXA) and high‐resolution peripheral quantitative computed tomography (HR‐pQCT) of the ultradistal and distal radius and tibia. In the HR‐pQCT images volumetric bone mineral density and cortical and trabecular structure measures, including cortical porosity, were calculated. Bone strength was estimated using micro–finite element analysis (µFEA). Differential strength estimates were obtained with and without open cortical pores. At the ultradistal and distal tibia, DMFx had greater intracortical pore volume (+52.6%, p = 0.009; +95.4%, p = 0.020), relative porosity (+58.1%, p = 0.005; +87.9%, p = 0.011) and endocortical bone surface (+10.9%, p = 0.031; +11.5%, p = 0.019) than DM. At the distal radius DMFx had 4.7‐fold greater relative porosity (p < 0.0001) than DM. At the ultradistal radius, intracortical pore volume was significantly higher in DMFx than DM (+67.8%, p = 0.018). DMFx also displayed larger trabecular heterogeneity (ultradistal radius: +36.8%, p = 0.035), and lower total and cortical BMD (ultradistal tibia: ?12.6%, p = 0.031; ?6.8%, p = 0.011) than DM. DMFx exhibited significantly higher pore‐related deficits in stiffness, failure load, and cortical load fraction at the ultradistal and distal tibia, and the distal radius than DM. Comparing nondiabetic Fx and Co, we only found a nonsignificant trend with increase in pore volume (+38.9%, p = 0.060) at the ultradistal radius. The results of our study suggest that severe deficits in cortical bone quality are responsible for fragility fractures in postmenopausal diabetic women. © 2013 American Society for Bone and Mineral Research     

Charlson Co‐morbidity Index and albumin significantly associated with fracture risk in peritoneal dialysis patients

Published literature on fracture in dialysis patients seldom addressed the effect of co‐morbidity and malnutrition. In this study, we reported the incidence and risk factors for fracture in peritoneal dialysis patients. Peritoneal dialysis patients who had fractures between 2006 and 2011 were recruited. Demographic data, details of fracture, Charlson Co‐morbidity Index (CCI) and biochemical parameters were also collected. Non‐fracture controls, matched for age, gender and duration of dialysis, were also recruited at ratio 1:1 for fracture risk analysis. The incidence of fracture was 1 in 37 patient‐years. The commonest site of fracture was neck of femur (n = 16, 55.2%). Twenty‐four patients (82.8%) developed fracture after slip and fall injury. Eight out of 17 self‐ambulatory patients (47.1%) became non‐ambulatory after fracture. Infection was the commonest complication during hospitalization. Univariant analysis demonstrated high CCI (P = 0.001), hypoalbuminaemia (P < 0.001), loss of self autonomy (P = 0.006) and non‐ambulatory state (P = 0.011) significantly associated with increased fracture risk. However, only CCI (odds ratio (OR) 1.373, P = 0.028) and albumin (OR 0.893, P = 0.025) increased fracture risk significantly on multivariant analysis. Bone profile and parathyroid hormone were not significant risk factors. To conclude, fracture associated with adverse outcome in peritoneal dialysis patients. High CCI score and hypoalbuminaemia significantly increase risk of fracture.     

Factors influencing late allograft valve failure

Allograft valves are a valuable valve replacement substitute in the surgical management of heart valve disease. It remains the valve substitute of choice in the reconstruction of the right ventricular outflow tract in children with congenital heart disease and in the Ross procedure. However, its durability remains suboptimal, particularly in children. This article reviews the mechanisms and factors implicated in late allograft dysfunction, with a focus on the evidence for an immunological cause for allograft failure. Unravelling the mechanisms of allograft valve failure may allow modification of the allograft to improve its long‐term durability.     

Tracking cerebral white matter changes across the lifespan: insights from diffusion tensor imaging studies

Delineating the normal development of brain white matter (WM) over the human lifespan is crucial to improved understanding of underlying WM pathology in neuropsychiatric and neurological conditions. We review the extant literature concerning diffusion tensor imaging studies of brain WM development in healthy individuals available until October 2012, summarise trends of normal development of human brain WM and suggest possible future research directions. Temporally, brain WM maturation follows a curvilinear pattern with an increase in fractional anisotropy (FA) from newborn to adolescence, decelerating in adulthood till a plateau around mid-adulthood, and a more rapid decrease of FA from old age onwards. Spatially, brain WM tracts develop from central to peripheral regions, with evidence of anterior-to-posterior maturation in commissural and projection fibres. The corpus callosum and fornix develop first and decline earlier, whilst fronto-temporal WM tracts like cingulum and uncinate fasciculus have protracted maturation and decline later. Prefrontal WM is most vulnerable with greater age-related FA reduction compared with posterior WM. Future large scale studies adopting longitudinal design will better clarify human brain WM changes over time.     

Effects of Physical Exercise Interventions on Stereotyped Motor Behaviours in Children with ASD: A Meta-Analysis

Journal of Autism and Developmental Disorders - Studies have reported that physical exercise reduces maladaptive stereotyped motor behaviours (SMB) in children with ASD, but these intervention...     

Use of telbivudine in kidney transplant recipients with chronic hepatitis B virus infection: A preliminary experience

Telbivudine is a relatively novel oral nucleoside analogue with favourable efficacy and tolerability in treatment‐naïve chronic hepatitis B virus (HBV) infection, but its data in kidney transplant recipients (KTRs) was lacking. The efficacy and tolerability of telbivudine in four treatment‐naïve HBsAg‐positive KTRs were reviewed (treatment duration 54 (36–72) months) HBV DNA declined from 2.6 × 10⁵(7.8 × 10³–1.5 × 10⁷) copies/mL at baseline to 170 (0.0–3.2 × 10⁴) copies/mL at 12 months, and became undetectable at 24 and 36 months (P = 0.060, 0.118 and 0.005 compared with baseline). Alanine aminotransferase levels dropped from 46.5 (30–48) IU/mL at baseline to 28 (13–45) IU/mL, 34.5 (15–71) IU/mL and 26 (12–41) IU/mL at 12, 24 and 36 months, respectively (P = 0.109, 0.715 and 0.068 compared with baseline). Serum creatinine level and estimated glomerular filtration rate (eGFR) remained stable after 36 months of treatment (P all > 0.05 compared with baseline). No virological breakthrough, cirrhosis or hepatocellular carcinoma occurred. Our pilot data suggests that telbivudine has favourable efficacy and renal safety profiles in HBsAg‐positive KTRs.