Mechanism of recurrence after radiofrequency catheter ablation of atrial fibrillation guided by complex fractionated atrial electrograms

Background A better understanding of the mechanisms of recurrent atrial fibrillation (AF) after radiofrequency ablation of complex, fractionated atrial electrograms (CFAEs) may be helpful for refining AF ablation strategies. Methods and results Electrogram-guided ablation (EGA) was repeated in 30 consecutive patients (mean age = 59 ± 8 years) for recurrent paroxysmal AF, 10 ± 4 months after the first ablation. During the first procedure, CFAEs were targeted without isolating all pulmonary veins (PVs). During repeat ablation, all PVs and the superior vena cava (SVC) were mapped with a circular catheter and the left atrium was mapped for CFAEs. EGA was performed until AF was rendered noninducible or all identified CFAEs were eliminated. During repeat ablation, ≥1 PV tachycardia was found in 83 PVs in 29 of the 30 patients (97%). Among these 83 PVs, 63 (76%) had not been completely isolated previously. During repeat ablation, drivers originating in a PV or PV antrum were identified only after infusion of isoproterenol (20 μg/min) in 12 patients (40%). At 9 ± 4 months of follow-up after the repeat ablation procedure, 21 of the 30 patients (70%) were free from recurrent AF and flutter without antiarrhythmic drugs. Conclusions Recurrence of AF after EGA is usually due to PV tachycardias. Therefore, it may be preferable to systematically map and isolate all PVs during the first procedure. High-dose isoproterenol may be helpful to identify AF drivers.     

Nonunion fracture healing: Evaluation of effectiveness of demineralized bone matrix and mesenchymal stem cells in a novel sheep bone nonunion model

Nonunion treatment has a high rate of success, although recalcitrant nonunion may determine the need for amputation. Therefore, new treatment options are continuously investigated in order to further reduce the risk of nonunion recurrence. This study aimed to (a) develop a new large animal model for bone atrophic nonunion and (b) compare the efficacy of demineralized bone matrix (DBM) and DBM in combination with mesenchymal stem cells (MSC) in the new nonunion model. The new model consists of a noncritical, full‐thickness segmental defect created in the sheep tibia, stabilized by an intramedullary nail, and involves the creation of a locally impaired blood supply achieved through periosteum excision and electrocauterization of the stump ends. Six weeks after defect creation, lack of hard tissue callus and established nonunion was observed in all operated tibiae both by radiographic and clinical evaluation. Nonunion was treated with allogeneic DBM or autologous MSC cultivated on DBM particles (DBM + MSC) for 1 day before implantation. Twelve weeks after treatment, radiographic, microtomographic, histologic, and histomorphometric analysis showed the formation of bone callus in DBM group, whereas the fracture healing appeared at an early stage in DBM + MSC group. Torsional strength and stiffness of the DBM group appeared higher than those of DBM + MSC group, although the differences were not statistically significant. In conclusion, a new sheep bone nonunion model resembling the complexity of the clinical condition was developed. DBM is an effective option for nonunion treatment, whereas MSC do not improve the healing process when cultivated on DBM particles before implantation.     

Respiratory oxygen uptake is associated with survival in a cohort of ventilated trauma and burn patients

Background

Little data is available in the literature about the role of end tidal oxygen in critically ill patients. We sought to identify the association between the level of respiratory oxygen and clinical outcomes in critically-ill ventilated trauma and burn patients.

Outcome of primary antiphospholipid syndrome in childhood

The objective of this paper is to investigate the long-term outcome of primary antiphospholipid syndrome (APS) in the paediatric age. The features of unselected patients with primary APS who had disease onset before the age of 16 years were retrospectively analysed in three Italian referralcentres. Clinical and laboratory manifestations were assessed to establish whether, at the end of follow-up, the final diagnosis was still primary APS or whether they had developed definite SLE or lupus-like syndrome. Fourteen patients, nine boys and five girls, who had the presenting clinical manifestation of APS between three and 13 years of age (median nine years) and were followed for two to 16 years (median six years). Six patients presented with deep vein thrombosis, five with cerebral stroke, two with peripheral artery occlusion and onewith myocardial infarction. During follow-up, four patients had one or more recurrences of vascular thrombosis. At last observation, 10 patients could still be classified as having primary APS, two had developed SLE, one lupus-like syndrome and one Hodgkin's lymphoma. In conclusion; our analysis suggests that some children who present with the features of primary APS may progress to develop SLE or lupus-like syndrome.     

Prevalence and clinical significance of anti-cyclic citrullinated peptide antibodies in juvenile idiopathic arthritis

BACKGROUND: Antibodies against cyclic citrullinated peptide (anti-CCP) are considered to be specific for rheumatoid arthritis (RA). OBJECTIVE: To assess the clinical significance of anti-CCP in a cohort of patients with juvenile idiopathic arthritis (JIA). METHODS: Anti-CCP were tested by an enzyme linked immunosorbent assay (ELISA) in serum samples from 109 patients with JIA (30 boys, 79 girls), with a mean age of 8.7 years (range 0.6-20.3) and mean disease duration of 3.6 years (range 3 months to 15.6 years). As control groups, anti-CCP were also tested in sera of 30 healthy children, 25 patients with juvenile onset systemic lupus erythematosus (SLE), and 50 adult patients (30 with RA, 20 with SLE). RESULTS: Positive anti-CCP values were found in sera of two patients with JIA (2%), one with polyarthritis, and one with oligoarthritis. Statistical analysis showed that anti-CCP were not associated with the presence of antinuclear antibodies, raised erythrocyte sedimentation rate, or erosions. In the control groups, none of the patients with juvenile onset SLE and only one of 20 adults with SLE were positive for anti-CCP, but 19/30 (63%) adults with RA showed anti-CCP positivity. CONCLUSIONS: Anti-CCP can be detected in children with JIA, but are less frequently present than in adults with RA.     

Electrovectorcardiographic study of negative T waves on precordial leads in arrhythmogenic right ventricular dysplasia: relationship with right ventricular volumes

In 24 cases of arrhythmogenic right ventricular (RV) dysplasia, the electrovectorcardiographic (ECG-VCG) behavior of T horizontal (wave and loop) was analyzed and the data compared with RV angiographic volumes. Arrhythmogenic RV dysplasia was diagnosed on the basis of echocardiographic and angiographic data in all subjects. At ECG, T wave was negative in V1 in nine subjects (37%), in V1-V2 in six (25%), in V1-V3 in two (8%), in V1-V4 in one (4%), in V1-V5 in two (8%), and in V1-V6 in four (16%). Nine subjects (37%) presented a bifid T wave in V2-V4. At VCG, T horizontal loop showed three morphologic characteristics: (1) counterclockwise rotation with a mean axis range of +15 degrees to -10 degrees (average, +5 degrees); (2) a figure-eight pattern with a mean axis range of +10 degrees to -40 degrees (average, -17 degrees); and (3) clockwise rotation with a mean axis range of -40 degrees to -110 degrees (average, -70 degrees). T wave changes seem to be primary and independent from QRS changes. RV and diastolic volumes ranged from 100 to 320 m1/m2 (average, 169 +/- 69). The extension of T wave negativity on precordial leads has a direct relationship with RV enlargement (r = 0.89, p less than 0.01). T changes are probably caused by dislocation of the left ventricle backwards secondary to RV dilatation, asynchronous RV repolarization, or intraparietal RV conduction defects.     

Clinical and diagnostic aspects of cystic insulinoma

Cystic endocrine tumors of the pancreas rarely occur, and only a few cases of cystic insulinoma have been reported to date. Diagnosis of insulinoma could be difficult if the functional activity is incomplete, possibly leading to blunted symptoms of hypoglycemia and failure in the laboratory to provide evidence of hyperinsulinemia. We report a clinical case of cystic insulinoma confirmed by histological examination after surgery, characterized by a high intracystic insulin concentration despite normal blood basal levels of the hormone. New diagnostic findings from dynamic tests and cystic fluid examination have been carefully focused on.     

Neonatal organization of the brain opioid systems controlling prolactin and luteinizing hormone secretion

It is known that the neural mechanisms which control PRL and gonadotropin secretion are different in male and female rats. The present experiments have been designed in order to analyze: 1) whether sexual differences exist in the responses of PRL and LH to the opioid antagonist naloxone; and 2) the mechanisms underlying these possible differences. To this purpose the responses of PRL and LH to the sc injection of either saline (0.5 ml) or naloxone (2.5 mg/kg) have been tested in the following four groups of animals: 1) normal male rats; 2) normal female rats; 3) female rats treated on the second day of life with 1.25 mg testosterone (androgenized female rats); and 4) male rats orchidectomized 2 days postnatally (demasculinized male rats). The naloxone challenge has been provided when the animals were 16, 26, and 60 days old; the animals were killed in the afternoon 20 min after treatment. The results obtained have shown that the acute injection of naloxone significantly decreases serum levels of PRL in normal males and in androgenized females at all ages considered. On the contrary, the opioid antagonist was always ineffective in normal females and in neonatally castrated males. The treatment of male rats with naloxone was without any effect on LH release before puberty (at 16 and 26 days of age), but induced a significant increase of serum LH titers after sexual maturation (60 days). In normal females, naloxone brought about a significant increase of serum LH only at 16 and 60 days (animals in estrus), but not at 26 days. Treatment with naloxone did not exert any significant effect on LH release in androgenized females and in deandrogenized males of any age. The present data suggest that, in the rat a sexual difference exists in the opiatergic control of PRL secretion; apparently, the central opioid systems which regulate PRL secretion develop towards a male pattern because of the presence of androgens in the neonatal period. On the contrary neonatal androgens do not seem to exert any important effect in directing the organization of the opiatergic mechanisms controlling LH release.