1,186 research outputs found
Cryoballoon Pulmonary Vein Isolation for the Treatment of Atrial Fibrillation and Issues in Follow-up Management
Since the fi rst publication proving the causal relation between electrically active muscular sleeves
in the pulmonary veins (PV) and the triggering of paroxysmal atrial fi brillation (AF) by ectopic beats
originating from them, numerous endocardial ablation techniques have been used to eliminate
this arrhythmia. Although well established as a standard procedure in the treatment of atrial
fi brillation, point-to-point radiofrequency ablation remains a challenging procedure, in which
manual operator skills and experience is highly variable. This currently translates in variable
success rates and high complication rates, making the risk-benefi t evaluation of this procedure
diffi cult to assess. Several devices have been engineered to simplify the circumferential ablation,
with the aim of permitting less experienced operator to achieve the endpoint of PV isolation
with reasonable procedure and fl uoroscopy times, and without a higher risk of complications
The European Academy laparoscopic “Suturing Training and Testing’’ (SUTT) significantly improves surgeons’ performance
The efficiency of suturing training and testing (SUTT) model by laparoscopy was evaluated, measuring the
suturing skill acquisition of trainee gynecologists at the beginning and at the end of a teaching course. During a workshop organized by the European Academy of Gynecological Surgery (EAGS), 25 participants with three different experience levels in laparoscopy (minor, intermediate and major) performed the 4 exercises of the SUTT model (Ex 1: both hands stitching and continuous suturing, Ex 2: right hand stitching and intracorporeal knotting,
Ex 3: left hand stitching and intracorporeal knotting, Ex 4: dominant hand stitching, tissue approximation and
intracorporeal knotting). The time needed to perform the exercises is recorded for each trainee and group and statistical analysis used to note the differences. Overall, all trainees achieved significant improvement in suturing time (p < 0.005) as measured before and after completion of the training. Similar significantly improved suturing time differences (p < 0.005) were noted among the groups of trainees with different laparoscopic experience. In conclusion a short well-guided training course, using the SUTT model, improves significantly surgeon’s laparoscopic suturing ability, independently of the level of experience in laparoscopic surgery
On the Age and Binarity of Fomalhaut
The nearby (d = 7.7 pc) A3V star Fomalhaut is orbited by a resolved dusty
debris disk and a controversial candidate extrasolar planet. The commonly cited
age for the system (200+-100 Myr) from Barrado y Navascues et al. (1997) relied
on a combination of isochronal age plus youth indicators for the K4V common
proper motion system TW PsA. TW PsA is 1.96 deg away from Fomalhaut, and was
first proposed as a companion by Luyten (1938), but the physicality of the
binarity is worth testing with modern data. I demonstrate that TW PsA is
unequivocally a physical stellar companion to Fomalhaut, with true separation
0.280+0.019-0.012 pc (57.4+3.9-2.5 kAU) and sharing velocities within 0.1+-0.5
km/s -- consistent with being a bound system. Hence, TW PsA should be
considered "Fomalhaut B". Combining modern HR diagram constraints with four
sets of evolutionary tracks, and assuming the star was born with protosolar
composition, I estimate a new isochronal age for Fomalhaut of 450+-40 Myr and
mass of 1.92+-0.02 Msun. Various stellar youth diagnostics are re-examined for
TW PsA. The star's rotation, X-ray emission, and Li abundances are consistent
with approximate ages of 410, 380, and 360 Myr, respectively, yielding a
weighted mean age of 400+-70 Myr. Combining the independent ages, I estimate a
mean age for the Fomalhaut-TW PsA binary of 440+-40 Myr. The older age implies
that substellar companions of a given mass are approximately one magnitude
fainter at IR wavelengths than previously assumed.Comment: ApJ Letters, in press, 5 pages in emulateapj, 1 figure. Minor edits.
Difference in velocity between Fomalhaut and TW PsA corrected to be 0.1+-0.5
km/
Simulation and Training of Gynaecological Skills
In order to offer our patients, the "state of the art" treatment in gynaecology, we need a structured teaching program for trainees concerning the gynaecological skills. In recent years, training and education in endoscopic surgery has been critically reviewed. Clinicians, both surgeons as gynaecologists who perform endoscopic surgery without proper training of the specific psychomotor skills, are at higher risk to increased patient morbidity and mortality. The traditional apprentice-tutor model is no longer valid for developing all skills necessary in gynaecological surgery, particularly in endoscopy. Endoscopic training should happen at both the theoretical and the practical skill level. The acquisition of the correct knowledge regarding general laparoscopy, hysteroscopy and standard level procedures is as important as learning the necessary psychomotor skills to successfully perform endoscopic manipulations. Training in the operating room can only start when it is proven that knowledge and skills are present. To learn and train total abdominal hysterectomy by laparotomy there are inexpensive simple models that can be used, which are easy to reproduce. The development, construction, cost, and utility of a low-cost and anatomically representative vaginal hysterectomy simulator also has been described. The complexity of modern surgery has increased the demands and challenges to surgical education and the quality control.info:eu-repo/semantics/publishedVersio
Electro-anatomical mapping of the left atrium before and after cryothermal balloon isolation of the pulmonary veins
Introduction: The 28 mm cryoballoon catheter is a device used for pulmonary vein isolation (PVI). The aim of this study was to evaluate the extent of the ablation in the antral regions of the left atrium. Methods and Results: Eighteen patients with drug refractory, symptomatic, paroxysmal AF were enrolled. A 3D electroanatomic reconstruction of the left atrium was made before and after successful PVI with the 28 mm cryoballoon. Markers were placed at the ostium. Sixteen patients were mapped. Fourteen patients had 4 veins each, and 2 patients had a common ostium of the left sided veins. All separate ostia were isolated in the antral region. The two common ostia showed ostial isolation. There was a significant difference in vein size between the common (29 and 31 mm) and the separate ostia (19∈±∈4 mm) (p∈<∈0.01). The performance of an additional segmental ablation if balloon PVI did not eliminate all electrical activity, did not influence the extent of the ablation. The earliest left atrial activation during sinus rhythm was located in the superior septal region before ablation in all patients. After ablation, two patients showed a substantial downward shift towards the middle and inferior septal region respectively (NS). Four patients demonstrated a slight downward shift of the first activation. Conclusions: In cryoballoon PVI, the majority of the veins undergo antral isolation. Veins with a diameter larger than the balloon, are isolated ostially. In individual cases, the left atrial activation sequence appears to be altered after ablation
ICDs at higher age and clinical risk factors
Background The implantable cardioverter defibrillator (ICD) is effective in preventing sudden cardiac death. However, in elderly patients (aged 75 years or older) the role of ICDs is still not well-defined and controversial. Methods We retrospectively analysed all clinical and survival data of all ICD patients who were ≥75 years at the date of implantation in the Erasmus MC, Rotterdam, the Netherlands and the University Hospital, Basel, Switzerland. Kaplan- Meier survival analysis was performed, and mortality predictors were identified. Mortality of the cohort was compared with a random sample of patients aged 60-70 years originating from the same database and to an age- and sex-matched cohort of Dutch persons. Results The study cohort consisted of 179 patients aged 75 years or older who were implanted between February 1999 and July 2008. The median follow-up time was 2.0 (IQR 2.8) years. Survival rates after 1, 2 and 3 years were 87, 82, 75 %, respectively. Survival was similar for primary and secondary prevention. Mortality in this study population could be predicted by combining four clinical risk factors: QRS duration >120 ms, NYHA class > II, renal failure and atrial fibrillation (AF). Survival was worse compared with the group of ICD patients aged 60-70 years and to the age- and sex-matched group of elderly persons. However, survival was not significantly worse when comparing elderly ICD patients without additional risk factors to the general population. Conclusions Elderly patients still have an acceptable survival probability independent of prevention indication, certainly if there are no additional clinical risk factors. The presence or absence of additional clinical risk factors should be taken into account when making the decision for imp
Long-term multi-wavelength studies of GRS 1915+105 I. A high-energy and mid-infrared focus with RXTE, INTEGRAL, and Spitzer
To date, mid-infrared properties of Galactic black hole binaries have barely
been investigated in the framework of multi-wavelength campaigns. Yet, studies
in this spectral domain are crucial to get complementary information on the
presence of dust and/or on the physical processes such as dust heating and
thermal bremsstrahlung. Here, we report a long-term multi-wavelength study of
the microquasar GRS 1915+105. On the one hand, we aimed at understanding the
origins of the mid-infrared emission, and on the other hand, at searching for
correlation with the high-energy and/or radio activities. We observed the
source at several epochs between 2004 and 2006 with the photometer IRAC and
spectrometer IRS, both mounted on the Spitzer Space Telescope. When available,
we completed our set of data with quasi-simultaneous RXTE and INTEGRAL
high-energy and/or Ryle radio observations from public archives. We then
studied the mid-infrared environment and activities of GRS 1915+105 through
spectral analysis and broad band fitting of its radio to X-ray spectral energy
distributions. We detected polycyclic aromatic hydrocarbon molecules in all but
one IRS spectra of GRS 1915+105 which unambiguously proves the presence of a
dust component, likely photoionised by the high-energy emission. We also argue
that this dust is distributed in a disc-like structure heated by the companion
star, as observed in some Herbig Ae/Be and isolated cool giant stars. Moreover,
we show that some of the soft X-ray emission emanating from the inner regions
of the accretion disc is reprocessed and thermalised in the outer part. This
leads to a mid-infrared excess that is very likely correlated to the soft X-ray
emission. We exclude thermal bremsstrahlung as contributing significantly in
this spectral domain.Comment: 46 pages, 6 tables, 6 figures, accepted in Ap
Cryoablation: how to improve results in atrioventricular nodal reentrant tachycardia ablation?
Ablation for atrioventricular nodal reentry tachycardia is very effective, with a potential for damage to the normal conduction system. Cryoablation is an alternative, as it allows cryomapping, which permits assessment of slow pathway elimination at innocent freezing temperatures, avoiding permanent damage to the normal conduction system. It is associated with shorter radiation times and the absence of heart block in all published data. We discuss in this overview different approaches of cryoenergy delivery (focusing on spot catheter ablation), and how lesion formation is influenced by catheter tip size, application duration, and freezing rate. Some advantages of cryoenergy are explained. Whether these features also apply for an approach with a cryoballoon, e.g. for atrial fibrillation is unclear
Multi-epoch Near-Infrared Interferometry of the Spatially Resolved Disk Around the Be Star Zeta Tau
We present interferometric observations of the Be star Zeta Tau obtained
using the MIRC beam combiner at the CHARA Array. We resolved the disk during
four epochs in 2007-2009. We fit the data with a geometric model to
characterize the circumstellar disk as a skewed elliptical Gaussian and the
central Be star as a uniform disk. The visibilities reveal a nearly edge-on
disk with a FWHM major axis of ~ 1.8 mas in the H-band. The non-zero closure
phases indicate an asymmetry within the disk. Interestingly, when combining our
results with previously published interferometric observations of Zeta Tau, we
find a correlation between the position angle of the disk and the spectroscopic
V/R ratio, suggesting that the tilt of the disk is precessing. This work is
part of a multi-year monitoring campaign to investigate the development and
outward motion of asymmetric structures in the disks of Be stars.Comment: Accepted for publication in the Astronomical Journal. 27 pages, 7
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