Impacto da Estimulação Vagal na Indução e Interrupção de Fibrilhação Auricular no Modelo do Coração de Coelho in Vivo

INTRODUCTION: Vagal activity is thought to influence atrial electrophysiological properties and play a role in the initiation and maintenance of atrial fibrillation (AF). In this study, we assessed the effects of acute vagal stimulation (vagus_stim) on atrial conduction times, atrial and pulmonary vein (PV) refractoriness, and vulnerability to induction of AF in the rabbit heart with intact autonomic innervation. METHODS: An open-chest epicardial approach was performed in 11 rabbits (New Zealand; 3.9-5.0 kg), anesthetized and artificially ventilated after neuromuscular blockade. A 3-lead ECG was obtained. Atrial electrograms were recorded along the atria, from right to left (four monopolar electrodes), together with a circular electrode adapted for proximal left PV assessment. Acute vagus nerve stimulation was obtained with bipolar electrodes (20 Hz). Epicardial activation was recorded in sinus rhythm, and the conduction time from right (RA) to left atrium (LA), and from RA to PVs, was measured in basal conditions and during vagus_stim. The atrial effective refractory period (ERP) and dispersion of refractoriness (Disp_A) were analyzed. Vulnerability to AF induction was assessed at the right (RAA) and left (LAA) atrial appendages and the PVs. Atrial stimulation (50 Hz) was performed alone or combined with vagus_stim. Heart rate and blood pressure were monitored. RESULTS: In basal conditions, there was a significant delay in conduction from RA to PVs, not influenced by vagus_stim, and the PV ERPs were shorter than those measured in LA and LAA, but without significant differences compared to RA and RAA. During vagus_stim, conduction times between RA and LA increased from 16+8 ms to 27+6 ms (p < 0.05) and ERPs shortened significantly in RA, LAA and LA (p < 0.05), but not in RAA. There were no significant differences in Disp_A. AF induction was reproducible in 45% of cases at 50 Hz and in 100% at 50 Hz+vagus_stim (p < 0.05). The duration of inducible AF increased from 1.0 +/- 0.2 s to 12.0 +/- 4.5 s with 50 Hz+vagus_stim (p < 0.01). AF lasted >10 s in 45.4% of rabbits during vagus_stim, and ceased after vagus_stim in 4 out of these 5 cases. In 3 animals, PV tachycardia, with fibrillatory conduction, induced with 50 Hz PV pacing during vagus_stim. CONCLUSIONS: Vagus_stim reduces interatrial conduction velocity and significantly shortens atrial ERP, contributing to the induction and duration of AF episodes in the in vivo rabbit heart. This model may be useful for the assessment of autonomic influence on the pathophysiology of AF.

Phototherapy in Childhood: a 17-Year Retrospective Study Regarding Effectiveness and Safety

Introduction: Skin diseases in paediatric age are often distressing conditions with significant impact in children’s psychosocial development. Additionally, systemic therapeutic options are often limited in childhood, due to its potential toxicity in this vulnerable group. Phototherapy is therefore an endorsed option for photo-responsive dermatological conditions. Objective and Methods:This observational retrospective study aims to access efficacy and safety of Phototherapy in our paediatric population. Relevant clinical data from 1996 to present concerning patients aged 18 years or less was collected. Results: 78 patients were included, of which64,1%was female. Mean age was 12,9 years (range 2-18). Distribution according to diagnosis was:47,4%psoriasis, 34,6% alopecia areata, 9,0% vitiligo, 9,0% other diagnosis. Mean number of cycles was 1,5 (range 1-7), with an average of 16,3 treatments per cycle and mean cumulative dose 134 J/cm2. 70,5% was treated with one single cycle. Topic and systemic PUVA were the first choice in 37,2% and 39,7%, respectively, while UVB TL01 and broadband UVB were used in 11,5% each. On the first cycle 67,5% improved, 14,3% showed no sustained clinical response and 19,5% were lost to follow-up. Psoriasis patients had the best response rates (81,8%), followed by alopecia areata (59,3%). Side effects occurred in 21%, being erythema the most common (12%). None led to therapeutic interruption. Discussion: Phototherapy is a safe and effective option in childhood, yet the withdraw rate might be an important limitation.

Office Hysteroscopy After Ultrasonographic Diagnosis of Thickened Endometrium in Postmenopausal Patients

The aim of our study was to access office hysteroscopy results in postmenopausal patients with thickened endometrium. A retrospective descriptive study was carried out on 245 postmenopausal patients submitted to office hysteroscopy after sonographic diagnosis of thickened endometriumin 20 consecutive months.Women were evaluated for age, hormonal therapy, hysteroscopic findings, procedure duration, complications and associated pain, and histological diagnosis. Patients with and without uterine bleeding were considered separately. Symptomatic patients were older and had longer procedure duration. The most frequent hysteroscopic finding was endometrial polyp in both groups. Pain was subjectively assessed in a numeric scale from 0 to 10 and median value was 4. There were no complications reported. Global neoplasia rate was 2.9% for asymptomatic patients and 16.4% for symptomatic ones (p<0.05). Thickened endometrium with postmenopausal metrorrhagia gave patients a significantly higher risk for neoplasia and hyperplasia.

The Impact of Multifocal Intraocular Lens in Retinal Imaging with Optical Coherence Tomography

Multifocal intraocular lenses (MF IOLs) have concentric optical zones with different dioptric power, enabling patients to have good visual acuity at multiple focal points. However, several optical limitations have been attributed to this particular design. The purpose of this study is to access the effect of MF IOLs design on the accuracy of retinal optical coherence tomography (OCT). Cross-sectional study conducted at the Refractive Surgery Department of Central Lisbon Hospital Center. Twenty-three eyes of 15 patients with a diffractive MF IOL and 27 eyes of 15 patients with an aspheric monofocal IOL were included in this study. All patients underwent OCT macular scans using Heidelberg Spectralis®. Macular thickness and volume values and image quality (Q factor) were compared between the two groups. There were no statistically significant differences between both groups regarding macular thickness or volume measurements. Retinal OCT image quality was significantly lower in the MF IOL group (p < 0.01). MF IOLs are associated with a significant decrease in OCT image quality. However, this fact does not seem to compromise the accuracy of spectral domain OCT retinal measurements.

Infections After Liver Transplantation: A Retrospective, Single-Center Study

Objective. To access the incidence of infectious problems after liver transplantation (LT). Design. A retrospective, single-center study. Materials and Methods. Patients undergoing LT from January 2008 to December 2011 were considered. Exclusion criterion was death occurring in the first 48 hours after LT. We determined the site of infection and the bacterial isolates and collected and compared recipient’s variables, graft variables, surgical data, post-LT clinical data. Results. Of the 492 patients who underwent LT and the 463 considered for this study, 190 (Group 1, 41%) developed at least 1 infection, with 298 infections detected. Of these, 189 microorganisms were isolated, 81 (51%) gram-positive bacteria (most frequently Staphylococcus spp). Biliary infections were more frequent (mean time of 160.4 167.7 days after LT); from 3 months after LT, gram-negative bacteria were observed (57%). Patients with infections after LT presented lower aminotransferase levels, but higher requirements in blood transfusions, intraoperative vasopressors, hemodialysis, and hospital stay. Operative and cold ischemia times were similar. Conclusion. We found a 41% incidence of all infections in a 2-year follow-up after LT. Gram-positive bacteria were more frequent isolated; however, negative bacteria were commonly isolated later. Clinical data after LT were more relevant for the development of infections. Donors’ variables should be considered in future analyses.