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We re-derive a formula relating the areal and luminosity distances, entirely in the framework of the classical Maxwell theory, assuming a geometric-optics type condition.

The arterial switch operation has become the procedure of choice for the simple transposition of the great arteries (TGA) while in the complex forms of the defect the staged approach is frequently implemented. The aim of this study is to compare groups of patients with simple transposition and children with the complex form of the defect and identify factors affecting early and late outcome.From 1997 to 2003, 135 consecutive neonates with TGA underwent arterial switch operation and simultaneous reparation of all associated defects. Univariate and multivariate analysis of perioperative variables and follow-up data was performed. Patients were divided into two groups. Group I (n=84, 62.2%) included neonates with simple transposition (TGA/IVS), Group II (n=51, 37.8%) included children with complex transposition (TGA/VSD).Overall early mortality was 8.1% and there was one late death (0.7%). One-month, 1-year and 5-year actuarial survival rates were 91.8, 91.1 and 91.1%, respectively. There were no differences in the early and late survival rate between groups. Reintervention rate for right ventricular outflow tract obstruction (RVOTO) was 13.3% (balloon plasty or reoperation). The freedom from reintervention at 1, 3 and 5 years was 98.4, 87.9 and 85.4%, respectively. There were no differences in the need for reintervention between groups. The significant differences between groups concerned: age at operation (p0.001), associated anomalies (p=0.002) including aortic arch anomalies (p=0.002) and coronary artery anomalies (p=0.02), application of delayed chest closure (p=0.015), and occurrence of sepsis (p=0.032). Risk factors for early death were: left ventricule dysfunction related to age at operation (p=0.016) and resternotomy in intensive care unit (p0.001). There were no differences between groups concerning these risk factors as far as circulatory arrest time, aorta clamping time, and early and late morbidity.The arterial switch operation can be the treatment of choice for various forms of TGA with low early and late mortality and morbidity rates. The main cause of early death is still left ventricular dysfunction. Such well-known predictors of poor outcome as presence of ventricular septal defect, coronary artery anomalies and aortic arch anomalies did not affect early and late findings. The presented approach of early simultaneous anatomical correction of TGA and all associated anomalies ensures good condition of children with low necessity for reintervention.

Heterotaxy syndromes comprise a great variety of possible cardiac defects. Anomalies of the pulmonary venous system are well recognized in heterotaxy syndromes but constitute a frequently underdiagnosed subgroup. The case report describes a girl with a rare form of supracardiac total anomalous pulmonary venous return via a right-sided vertical vein to the right innominate vein in heterotaxy syndrome with dextrocardia, unbalanced atrioventricular septal defect with severe left ventricular hypoplasia, and transposition of the great arteries with pulmonary stenosis. Careful evaluation and imaging before surgical repair is crucial for such complex cardiac anomalies.

It was suggested earlier that the gravitational redshift formula can be invalid when the effect of the backscattering is strong. It is demonstrated here numerically, for an exemplary electromagnetic pulse that is: i) initially located very close to the horizon of a Schwarzschild black hole and ii) strongly backscattered, that a mean frequency does not obey the standard redshift formula. Redshifts appear to depend on the frequency and there manifests a backscatter-induced blueshift in the outgoing radiation., 4 pages, 2 figures. To appear in the Class. Q. Grav

Gap junctions created by a family of connexin proteins play an important role in the development of human heart. It has been previously shown that the abnormalities of right ventricular outflow tract are related to an altered level of expression of connexin 43. The right ventricular outflow tract narrowing, stenosis, or atresia of the main pulmonary artery and hypertrophy of the right ventricle are observed in tetralogy of Fallot. The aim of the current study was to determine the distribution of connexin 43 on the surface of human cardiomyocytes obtained during reparative surgery for tetralogy of Fallot. Connexin 43 distribution in these cells was compared with distribution of connexin 43 in cardiomyocytes obtained from patients without right ventricular outflow tract pathology. Cardiomyocytes isolated from tissue biopsy were cultured on collagen substratum, fixed with paraformaldehyde, and incubated with goat antihuman connexin 43 antibodies and secondary donkey antigoat antibodies conjugated with fluorescent indocarbocyanine. Z-series of optical sections were recorded using a laser scanning confocal microscope. Three-dimensional data stacks were visualized using volume-rendering techniques. Images of connexin 43 fluorescence revealed a pattern of three-dimensional distribution of connexin on the surface of an individual cardiomyocyte. Cardiomyocytes from tetralogy of Fallot and hearts with normal right ventricular outflow tract differ in the organization of connexin 43. Cardiomyocytes from tetralogy of Fallot hearts revealed disturbed distribution of connexin 43. The protein is located irregularly on the entire surface of the cell. In the controls, connexin 43 can be visualized within the intercalated disks only. These disturbances may influence heart maturation, cause hypertrophy of the right ventricle, and induce severe arrhythmias in children with tetralogy of Fallot.

The gravitational redshift formula is usually derived in the geometric optics approximation. In this note we consider an exact formulation of the problem in the Schwarzschild space-time, with the intention to clarify under what conditions this redshift law is valid. It is shown that in the case of shocks the radial component of the Poynting vector can scale according to the redshift formula, under a suitable condition. If that condition is not satisfied, then the effect of the backscattering can lead to significant modifications. The obtained results imply that the energy flux of the short wavelength radiation obeys the standard gravitational redshift formula while the energy flux of long waves can scale differently, with redshifts being dependent on the frequency., Comment: Revtex, 5 p. Rewritten Sec. II, minor changes in Secs III - VII. To appear in the Classical and Quantum Gravity

Examination of exercise function of Fontan patients and comparison with healthy control subjects.Fourteen patients (6 males, 8 females; age: 5.7-17 years, mean 8.1 years) after Fontan repair in New York Heart Association (NYHA) class I with rest O(2)sat85% requiring no cardiovascular medications performed graded exercises on a treadmill 0.5-3.2 years postoperatively (mean 1.8 years). During the tests the heart and respiratory rate, blood pressure, oxygen uptake, carbon dioxide production, minute ventilation, tidal volume and O(2)sat were recorded. Spirometry was performed before and during exercise.The peak VO(2)max in Fontan patients was significantly reduced compared with controls (p = 0.0002). Other parameters: anaerobic threshold (p = 0.0001); pulsO(2) (p = 0.00005); peak minute ventilation (p = 0.0014); physiological dead space to tidal volume ratio at peak exercise (p = 0.0004); maximal work rate (p = 0.00008); exercise time (p = 0.00003) were significantly reduced in univentricular patients. The heart rate at peak exercise was lower in the patients (p = 0.0003) and O(2)sat dropped significantly (p = 0.003).The aerobic capacity, work and ventilatory parameters in Fontan patients are markedly reduced compared with controls. The anaerobic threshold was significantly lower. The decreased O(2)sat at peak exercise may suggest intrapulmonary shunting.

Hypoplastic left heart syndrome with dextrocardia and situs solitus is a very rare condition. We describe a 3.5-year-old male child with this constellation who underwent multistage repair and a successful extracardiac Fontan operation in our hospital.

Background The lack of early biomarkers for acute kidney injury (AKI) seriously inhibits the initiation of preventive and therapeutic measures for this syndrome in a timely manner. We tested the hypothesis that insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2), both inducers of G1 cell cycle arrest, function as early biomarkers for AKI after congenital heart surgery with cardiopulmonary bypass (CPB). Methods We prospectively studied 51 children undergoing cardiac surgery with CPB. Serial urine samples were analyzed for [TIMP-2]•[IGFBP7]. The primary outcome measure was AKI defined by the pRIFLE criteria within 72 hours after surgery. Results 12 children (24%) developed AKI within 1.67 (SE 0.3) days after surgery. Children who developed AKI after cardiac surgery had a significant higher urinary [TIMP-2]•[IGFBP7] as early as 4 h after the procedure, compared to children who did not develop AKI (mean of 1.93 ((ng/ml)2/1000) (SE 0.4) vs 0.47 ((ng/ml)2/1000) (SE 0.1), respectively; p

Cor triatriatum dexter is a very rare cardiac anomaly in which a membrane divides the right atrium into two chambers [1]. Depending on the degree of right atrial obstruction, the clinical sign of these anatomic variations may be neonatal cyanosis necessitating urgent surgical intervention; some patients are asymptomatic and reach adulthood without therapy [2]. Echocardiographic diagnosis can be difficult [1, 3]. We report on a newborn referred for severe neonatal cyanosis with the diagnosis of cor triatriatum dexter with obstruction of the right ventricular inflow. Surgical intervention led to complete recovery. The male neonate was spontaneously born at 41 weeks of gestation after an uncomplicated pregnancy with a birth weight of 3550 g. After the initial uncomplicated situation, central cyanosis with a transcutaneous oxygen saturation of 85% led to admission to the neonatal intensive care unit. The echocardiographic evaluation revealed a large, floating membrane within the right atrium connected to the eustachian and thebesian valve at the site of the connection to the inferior vena cava and the atrial septum, respectively, without hemodynamic compromise, but with right-to-left shunting through the secundum atrial septal defect. The membrane formed a ‘‘windsock’’ especially in diastole when it was bulging into the right ventricular inflow tract. Laterally, there was an opening within the membrane permitting turbulent blood flow from the right atrium to the right ventricle (mean pressure gradient 2 mmHg). Surgery was performed then at the age of 4 weeks in a stable patient. After an oblique right atrial opening the membrane was exposed with its attachments to the eustachian valve, thebesian valve, and laterally to the crista terminalis. There were no attachments to the interatrial septum. The membrane could be invaginated completely into the right ventricle, creating an inflow obstruction. The tricuspid valve was normal. The membrane was completely excised and the atrial septal defect (secundum type) was closed directly. The postoperative course was uneventful and the patient was extubated on the day of surgery and discharged home on the 13th day after surgery. Remnants of the right valve of the embryonic sinus venosus are not uncommon and are recognized as the normal eustachian and thebesian valves [3]. In a series of 300 consecutively autopsied patients, almost 70% of the specimens presented such valves [4]. Clinical manifestation of cor triatriatum dexter includes a wide spectrum. It can be completely asymptomatic and detected incidentally or at necropsy. During fetal life, marked nuchal edema may be associated with significant obstruction of the right ventricular inflow [5]. Also, significant obstruction may lead to the underdevelopment of the right heart structures: tricuspid valve abnormalities including Ebstein anomaly, hypoplastic right ventricle and pulmonary stenosis or atresia. After birth, neonatal cyanosis may appear due to the systemic venous blood flow directed toward the atrial septum and consecutively right-to-left shunting [1]. In the M. Loeff R. Kozlik-Feldmann H. Netz R. D. Pozza (&) Department of Pediatric Cardiology, Klinikum Groshadern, Ludwig-Maximilians-University, Marchioninistr. 15, 81377 Munich, Germany e-mail: Robert.DallaPozza@med.uni-muenchen.de

Objective: The operative outcome of the Norwood procedure for hypoplastic left heart syndrome is still not satisfactory. Conflicting reports concern factors associated with early Norwood procedure mortality and the reasons for the instability after surgery are not sufficiently understood. The purpose of this study was to determine some perioperative factors influencing early (30 days) outcome. Methods :W e retrospectively analyzed a group of 30 consecutive children with hypoplastic left heart syndrome (aged 5‐39 days) who underwent Norwood procedure in 1997 and 1998. The following factors were considered and statistically analyzed: operative age, birth weight, operative weight, serum level of bilirubin, aminotransferases, creatinine, urea, arterial blood gasses, anatomic subgroups, ascending aorta and arch size, systemic to pulmonary modified right Blalock‐Taussig shunt size, cardiopulmonary circulatory arrest time, cardiopulmonary bypass time, and delayed chest closure. Eighteen patients underwent hemi-Fontan procedure with one late death and the modified Fontan operation was performed in 16 of them (one late death). Results: The early mortality was 37%. Seven deaths (64%) occurred during the first 24 h after operation. There was a significant difference between survivals and non-survivals in: birth weight (Pa 0:047), operative age (Pa 0:016), preoperative serum level of bilirubin (Pa 0:044), and cardiopulmonary circulatory arrest time (Pa 0:006). The other assessed factors were not found to be predictors of early mortality. All 16 survivals followed up are in New York Heart Association class I or II. Conclusions: Anatomic and functional status of the patient, as well as procedural factors are related to Norwood operation early mortality. High mortality in hypoplastic left heart syndrome after stage I surgery indicates the necessity of assessing all factors which may determine further improvement in the outcome. q 2000 Elsevier Science B.V. All rights reserved.

This article investigates the interaction of a spherically symmetric massless scalar field with a strong gravitational field. It focuses on the propagation of waves in regions outside any horizons. The two factors acting on the waves can be identified as a redshift and a backscattering. The influence of backscattering on the intensity of the outgoing radiation is studied and rigorous quantitative upper bounds obtained. These show that the total flux may be decreased if the sources are placed in a region adjoining an apparent horizon. Backscattering can be neglected in the case $2m_0 /R<< 1$, that is when the emitter is located at a distance from a black hole much larger than the Schwarzschild radius. This backscattering may have noticeable astrophysical consequences., Revtex, 16 pages, 3 figures

We investigate spherical, isothermal and polytropic steady accretion models in the presence of the cosmological constant. Exact solutions are found for three classes of isothermal fluids, assuming the test gas approximation. The cosmological constant damps the mass accretion rate and - above certain limit - completely stops the steady accretion onto black holes. A "homoclinic-type" accretion flow of polytropic gas has been discovered in AdS spacetimes in the test-gas limit. These results can have cosmological connotation, through the Einstein--Straus vacuole model of embedding local structures into Friedman-Lemaitre-Robertson-Walker spacetimes. In particular one infers that steady accretion would not exist in the late phases of the Penrose's scenario of the evolution of the Universe, known as the Weyl curvature hypothesis., Comment: 19 pages, 10 figures

Recent analytic results concerning stationary, self-gravitating fluids in Newtonian theory are discussed. We give a theorem that forbids infinitely extended fluids, depending on the assumed equation of state and the rotation law. This part extends previous results that have been obtained for static configurations. The second part discusses a Sobolev bound on the mass of the fluid and a rigorous Jeans-type inequality that is valid in the stationary case., A talk given at the Spanish Relativity Meeting in Portugal 2012. To appear in Progress in Mathematical Relativity, Gravitation and Cosmology, Proceedings of the Spanish Relativity Meeting ERE2012, University of Minho, Guimaraes, Portugal, 3-7 September 2012, Springer Proceedings in Mathematics & Statistics, Vol. 60

In this paper we investigate a steady accretion within the Einstein-Straus vacuole, in the presence of the cosmological constant. The dark energy damps the mass accretion rate and --- above certain limit --- completely stops the steady accretion onto black holes, which in particular is prohibited in the inflation era and after (roughly) $10^{12}$ years from Big Bang (assuming the presently known value of the cosmological constant). Steady accretion would not exist in the late phases of the Penrose's scenario - known as the Weyl curvature hypothesis - of the evolution of the Universe., misprints corrected, matches published version

In a recent paper we investigated stationary, relativistic Bondi-type accretion in Schwarzschild-(anti-)de Sitter spacetimes. Here we study their stability, using the method developed by Moncrief. The analysis applies to perturbations satisfying the potential flow condition. We prove that global isothermal flows in Schwarzschild-anti-de Sitter spacetimes are stable, assuming the test-fluid approximation. Isothermal flows in Schwarzschild-de Sitter geometries and polytropic flows in Schwarzschild-de Sitter and Schwarzschild-anti-de Sitter spacetimes can be stable, under suitable boundary conditions., 6 pages

Background— The balance of systemic, pulmonary, and coronary blood flow after the Norwood operation for hypoplastic left heart syndrome (HLHS) is critical to early survival. We hypothesized that a right ventricle to pulmonary artery conduit (instead of a systemic to pulmonary artery shunt) would result in hemodynamic changes consistent with a more stable balance of systemic, pulmonary, and coronary perfusion. Methods and Results— Hemodynamic data were obtained during cardiac catheterization before the hemi-Fontan procedure from 24 patients with HLHS; the first 10 had a Norwood operation with a systemic to pulmonary artery shunt, and the latter 14 had the Norwood operation with a right ventricle to pulmonary artery conduit. Significant differences were present, with the right ventricle to pulmonary artery conduit group having a higher aortic diastolic pressure (55 versus 42 mm Hg), a narrowed systemic pulse pressure (43 versus 64 mm Hg), a lower Qp:Qs (0.92 versus 1.42), a higher coronary perfusion pressure (46 versus 32 mm Hg), and a higher ratio of pulmonary artery diameter to descending aorta diameter (1.51 versus 1.37). Conclusions— We conclude that, in HLHS after the Norwood operation, the right ventricle to pulmonary artery conduit modification produces hemodynamic changes consistent with improved coronary perfusion and a more favorable distribution of systemic, pulmonary, and coronary blood flow.

We describe a successfully treated pseudoaneurysm of the ascending aorta in a 2-month-old infant after a previous operation due to hypoplastic left heart complex. After a rapidly progressing respiratory tract obstruction as a first symptom, echocardiography revealed a huge aneurysmal formation originating from the anterior and right lateral wall of the ascending aorta. A patch aortoplasty was employed.

We investigate accreting disk systems with polytropic gas in Keplerian motion. Numerical data and partial analytic results show that the self-gravitation of the disk speeds up its rotation -- its rotational frequency is larger than that given by the well known strictly Keplerian formula that takes into account the central mass only. Thus determination of central mass in systems with massive disks requires great care -- the strictly Keplerian formula yields only an upper bound. The effect of self-gravity depends on geometric aspects of disk configurations. Disk systems with a small (circa $10^{-4}$) ratio of the innermost radius to the outermost disk radius have the central mass close to the upper limit, but if this ratio is of the order of unity then the central mass can be smaller by many orders of magnitude from this bound., Comment: 20 pages, 10 figures

Spherical configurations that are very massive must be surrounded by apparent horizons. These in turn, when placed outside a collapsing body, have a fixed area and must propagate outward with a velocity equal to the velocity of radially outgoing photons. That proves, within the framework of the (1+3) formalism and without resorting to the Birkhoff theorem, that apparent horizons coincide with event horizons in electrovacuum., Comment: 4, Poland July 1993, 24 pages, latex

We demonstrate that the Penrose inequality is valid for spherically symmetric geometries even when the horizon is immersed in matter. The matter field need not be at rest. The only restriction is that the source satisfies the weak energy condition outside the horizon. No restrictions are placed on the matter inside the horizon. The proof of the Penrose inequality gives a new necessary condition for the formation of trapped surfaces. This formulation can also be adapted to give a sufficient condition. We show that a modification of the Penrose inequality proposed by Gibbons for charged black holes can be broken in early stages of gravitational collapse. This investigation is based exclusively on the initial data formulation of General Relativity., Comment: plain tex

The authors investigate the validity of the Penrose inequality in a class of strongly curved, massive and conformally flat geometries. Numerical analysis has confirmed it on an initial Cauchy slice generated by massive spheroids, both oblate and prolate.

The use of a ventricular assist device (VAD) is a life-saving option for patients with heart failure refractory to conventional therapy.To assess the effect of VAD on outcomes of heart transplantation in children.Between October 1988 and June 2009, a consecutive series of 95 children (mean age 8.6 + or - 6.7 years, range 5 days-17.9 years) underwent heart transplantation: patients in group 1 (n = 11) received VAD as a bridge to cardiac transplantation (left ventricular VAD in 4, biventricular VAD in 7), and patients in group 2 (n = 84) underwent heart transplantation without previous cardiac support using VAD. The indication for heart transplantation was cardiomyopathy/myocarditis in 66 (69.5%) of children and congenital heart disease in 29 (30.5%) patients.Congenital heart disease was diagnosed more often in group 2 than in group 1 (p = 0.047). The two groups did not differ significantly with respect to age, weight and parameters of preoperative liver and kidney function (except for aspartate aminotransferase activity, p = 0.020). The mean waiting time for transplantation was 64.2 + or - 87.4 days (range 1-443 days) and did not differ between the groups. The mean follow-up was 6.8 + or - 5.4 years (range 1 day-17.6 years). Mortality during long-term follow-up was 9.1% (n = 1) in group 1 and 20.2% (n=17) in group 2 (p = 0.632). We found no significant differences in postoperative ventilatory support time (p = 0.773), duration of hospital stay (p = 0.853), and incidence of acute rejection episodes (p = 0.575).The use of VAD as a bridge to heart transplantation in children with severe heart failure had no negative effect on treatment outcomes.

Objective: The right ventricle-to-pulmonary artery (RV-PA) shunt in the Norwood procedure (NP) for children with hypoplastic left-heart syndrome (HLHS) provides stable early hemodynamics and improves survival in many centers. However, lower pulmonary-to-systemic flow ratio causes early cyanosis and may require earlier second-stage procedure. The aim of the study was to present shunt-related results after NP with RVPA shunt and our technique of RV-PA shunt construction. Methods: Between June 2001 and August 2010, 236 children with HLHS and variants underwent NP with RV-PA shunt, and were operated on by the same surgeon. The medical records were retrospectively reviewed. Results: To date, 180 children at a mean age of 7.0 1.6 months with a mean weight of 6.4 0.9 kg underwent second-stage procedure. The mean systemic oxygen saturation before stage 2 operation was 74.8 6.6% and mean arterial partial oxygen pressure was 32.8 6.7 mmHg. These two parameters were significantly lower than after NP (p = 0.029, p < 0.001, respectively). Between stage 1 and 2 operation, three children (1.3%) died due to the shunt obstruction. Four children (1.7%) underwent re-operations due to shunt problems (one of them died), and the other four (1.7%), stent implantation in RV-PA shunt. Two infants (1.1%) developed aneurysm of the right ventricle infundibulum, which was resected during stage 2 without complications. One child required early (before fifth month of age) second-stage procedure due to the shunt obstruction. The patients with right-sided to the neo-aortacourse of the RV-PA shunthad significantlymorefrequent delayed sternal closure after NP than children with left-sided shunt (35.5% vs 14.1%; p = 0.008). Conclusions: The RV-PA shunt can be a safe and efficient technique in providing optimal pulmonary blood flow in the children with HLHS after Norwood procedure, performed with minimal rate of complications. In our experience, the use of RV-PA shunt in NP does not require earlier second-stage procedure. # 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

Objective:The populationofchildren who receivedrightventricle-to-pulmonaryartery shunt (RV-PA) atNorwood procedure (NP)is growing,but limited data are available regarding the long-term outcome. Theaim of this study was to present operative outcomes and mid-term hemodynamics and to assess the impact of the residual aortic obstruction on the results in patients undergoing three-staged surgery with RV-PA application at NP. Methods: Between June 2001 and June 2009, 229 children with hypoplastic left heart syndrome (HLHS) and variants underwent NP with RV-PA; 172 have proceeded to stage II and 95 to stage III. The medical records (clinical data, echocardiographic records, cardiac catheterization reports, electrocardiograms, and surgical notes) were retrospectively reviewed. Results: The later era of NP was associated with significantly better outcome (2001—2004: 1- and 5-years’ survival were 64.3% and 59.8%, respectively; 2005—2009: 1- and 4-years’ survival were 93.1% and 86.9%, respectively) (p < 0.001). There was no association between long-term survival and diagnosis (HLHS/HLHS variant) (p = 0.39). The incidence of depressed ventricular function and moderate or severe systemic atrioventricular valve regurgitation among the children who required balloon aortoplasty (BA) before stage IIsurgerywassignificantlyhigher than inchildren without aorticarchobstruction(p =0 .027,p = 0.008,respectively). In midterm follow-up, BA had no significant influence on the actuarial survival (p = 0.089). No ventricular arrhythmias were noticed at any stage. Conclusions: The RV-PA shunt is a safe technique that does not seem to impair systolic or electrical ventricular function; its outcomes continue to improve with growing experience. Combined cardiologic interventional and surgical procedures are required to optimize the outcomes. # 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

The Thorne hoop conjecture is an attempt to make precise the notion that gravitational collapse occurs if enough energy is compressed into a small enough volume, with the `size' being defined by the circumference. We can make a precise statement of this form, in spherical symmetry, using the Brown-York mass as our measure of the energy. Consider a spherical 2-surface in a spherically symmetric spacetime. If the Brown-York mass, $M_{BY}$, and the circumference, $C$, satisfy $C < 2��M_{BY}$, then the system must either have emerged from a white hole or will collapse into a black hole. We show that no equivalent result can hold true using either the Liu-Yau mass, $M_{LY}$ or the Wang-Yau mass, $M_{WY}$. This forms a major obstacle to any attempt to establish a Thorne-type hoop theorem in the general case based on either the Liu-Yau or the Wang-Yau mass., 4 pages; accepted for publication in Physical Review Letters

We compare Newtonian and general relativistic descriptions of the stationary accretion of self-gravitating fluids onto compact bodies. Spherical symmetry and thin gas approximation are assumed. Luminosity depends, among other factors, on the temperature and the contribution of gas to the total mass, in both—general relativistic (L GR ) and Newtonian (L N )—models. We discover a remarkable universal behavior for transonic flows: the ratio of respective luminosities L GR /L N is independent of the fractional mass of the gas and depends on asymptotic temperature. It is close to 1 in the regime of low asymptotic temperatures and can grow several times at high temperatures. These conclusions are valid for a wide range of polytropic equations of state.

We studied a steadily accreting, geometrically thick disk model that selfconsistently takes into account selfgravitation of the polytropic gas, its interaction with the radiation and the mass accretion rate. The accreting mass is injected inward in the vicinity of the central $z=0$ plane, where also radiation is assumed to be created. The rest of the disk remains approximately stationary. Only conservation laws are employed and the gas-radiation interaction in the bulk of the disk is described in the thin-gas approximation. We demonstrate that this scheme is numerically viable and yields a structure of the bulk that is influenced by the radiation and (indirectly) by the prescribed mass accretion rate. The obtained disk configurations are typical for environments in Active Galactic Nuclei (AGN), with the central mass of the order of $10^7 M_{\astrosun}$ to $10^8 M_{\astrosun}$, quasi-Keplerian rotation curves, disk masses ranging from about $10^6 M_{\astrosun}$ to $10^7 M_{\astrosun}$, and the luminosity ranging from $10^6 L_{\astrosun}$ to $10^9 L_{\astrosun}$. These luminosities are much lower than the corresponding Eddington limit., Comment: Changes according to the version accepted by Astronomy & Astrophysics

A general framework for the study of the formation of apparent horizons is found. A necessary condition is given in momentarily static nonspherical geometries with non-negative (locally) sectional curvatures. Known results concerning the existence of trapped surfaces are reviewed in a class of conformally flat nonspherical systems.

Assume one has a slice in a homogeneous open k=0 Friedmann-Lemaitre universe, with spherically symmetric inhomogeneities. Assume that inhomogeneities do not change (initially) the rate of expansion of the volume of the slice. Then trapped surfaces have to form if perturbations are compacted in a sufficiently small volume. Assuming in addition that the gravitational momentum is not changed, the authors conclude that trapped surfaces can appear only if the mass of perturbation is comprised in a sufficiently small volume. The mass of inhomogeneities is bounded from above by a doubled radius of the volume. A bound for the size of a trapped region is found, which depends on the cosmological energy density.

The coexistence of tricuspid atresia and common arterial trunk is extremely rare. We present a successful three-stage surgical treatment of this defect. The first stage included disconnection of the pulmonary arteries from the common trunk, atrial septectomy and systemic-to-pulmonary shunt; the second stage, a hemi-Fontan procedure; and the third stage, a fenestrated Fontan completion. The child is now 8 years old and is developing well.

The appearance of re-stenosis after repair of an interrupted aortic arch may be a surgical challenge due to adhesions. Here, we describe an approach using off-pump coronary artery bypass grafting techniques to reach the descending aorta through a median sternotomy in a patient with aortic arch stenosis after conduit repair. The 17-year-old patient with diagnoses of interrupted aortic arch and ventricular septal defect presented after two previous operations (one left lateral thoracotomy and one median sternotomy) with a stenosed vascular graft between ascending and descending aorta. Surgery was done via re-sternotomy without cardio-pulmonary bypass. An extraanatomic graft was used to connect ascending and descending aorta. When performing the distal anastomosis, the heart was exposed using a standard suction device. This case demonstrates that the use of modern techniques may facilitate surgical approaches dramatically. In our opinion the above-described technique is the first choice for all patients requiring arch repair following multiple previous operations, performed via sternotomy and thoracotomy.

We consider a family of spherical three dimensional spacelike slices embedded in the Schwarzschild solution. The mean curvature is constant on each slice but can change from slice to slice. We give a simple expression for an everywhere positive lapse and thus we show how to construct foliations. There is a barrier preventing the mean curvature from becoming large, and we show how to avoid this so as to construct a foliation where the mean curvature runs all the way from zero to infinity. No foliation exists where the mean curvature goes from minus to plus infinity. There are slicings, however, where each slice passes through the bifurcation sphere $R = 2M$ and the lapse only vanishes at this one point, and is positive everywhere else, while the mean curvature does run from minus to plus infinity. Symmetric foliations of the extended Schwarzschild spacetime degenerate at a critical point, where we show that the lapse function exponentially approaches zero., Comment: 2 new figures, new references, 8 pages. Matches the version accepted by the Physical Review D

Necessary and sufficient conditions for the formation of trapped surfaces in a class of nonspherical systems are proven. Massive singularities, if they exist in the geometries discussed, are always surrounded by apparent horizons. Milder singularities that are strongly nonspherical might be naked. Implications concerning the validity of the hoop conjecture are discussed.

Objective Heart–lung transplantation for patients with pulmonary atresia and ventricular septal defect is challenging. The aim of the study was to present a single-center experience with heart–lung transplantation in this difficult group of patients. Methods A retrospective review identified 9 patients aged 4.1 to 45.6 years (median, 25.4 years) with pulmonary atresia and ventricular septal defect who underwent heart–lung transplantation. Four (44.4%) patients had previous heart operations: 3 of them had palliative procedures (systemic-to-pulmonary shunts), and 1 had multistage correction. A standard transplantation method was used, with the exception of 1 patient with heterotaxy syndrome who underwent a modified operation. Major aortopulmonary collateral arteries were controlled by using various techniques. Results Follow-up ranged between 2 days and 12.6 years (median, 1.2 years). The hospital mortality rate was 22.2% (n = 2). In the late postoperative period, 3 patients died. The survival curve was similar to that of patients with other diagnoses undergoing heart–lung transplantation. The median length of intensive care unit stay was 58 days (range, 22–82 days), and the median length of hospital stay was 83 days (range, 35–136 days). The most common early complication was bleeding requiring re-exploration. In all cases the bleeding was proved to be from collateral vessels. Conclusions Heart–lung transplantation in patients with pulmonary atresia and ventricular septal defect requires carefully planned and meticulously performed surgical intervention. This management should be taken into consideration as a future option if the specific anatomy is uncorrectable in early childhood, and the palliative procedures should be avoided.

Right (systemic) ventricular (RV) failure in patients with transposition of the great arteries (TGA) after the Senning operation is a well-known late complication. Although double switch operations have been advocated by some groups, orthotopic heart transplantation (HTx) remains the only definitive option to treat these patients. However, there is a high mortality rate for patients on transplant waiting lists, and the use of ventricular assist devices (VADs) is often required as a bridge to HTx.

Analytic methods show stability of the stationary accretion of test fluids but they are inconclusive in the case of self-gravitating stationary flows. We investigate numerically stability of those stationary flows onto compact objects that are trans-sonic and rich in gas. In all studied examples solutions appear stable. Numerical investigation suggests also that the analogy between sonic and event horizons holds for small perturbations of compact support but fails in the case of finite perturbations.

The authors prove that the binding energy for a spherical distribution of matter at rest, in general relativity, is bounded by the Newtonian value for a shell with same mass and radius. This confirms a conjecture of Arnowitt, Deser and Misner (1965).

The non‐Abelian monopole solution of Bogomolny, Prasad, and Sommerfield is chosen as a part of the Cauchy data for the evolution of Einstein–Yang–Mills–Higgs equations. Momentarily static spherically symmetric data for gravitational fields are obtained numerically via the Lichnerowicz equation. In the case of generic scaling of fields initial data with trapped surfaces were found.

Combined poisoning with calcium-channel blockers and β-blockers is usually associated with severe heart failure. This report shows the effectiveness of emergency extracorporeal life support in treating life-threatening simultaneous propranolol and verapamil intoxication. A 15-year-old girl presented in cardiogenic shock after alcohol consumption and a propranolol and verapamil overdose; plasma concentrations: propranolol, 0.53 m/mL; verapamil, 1.06 mg/mL. She was successfully resuscitated with extracorporeal life support. Therapeutic plasma exchange was initiated. Extracorporeal support was discontinued 70 hours later. The patient made a full recovery. Simultaneous verapamil and propranolol overdoses can cause severe hemodynamic compromise and arrest of electrical and mechanical function of the heart. Emergency extracorporeal life support can successfully maintain vital organ blood flow and allows time for drug metabolism, redistribution, and removal. Therapeutic plasma exchange may reduce the time of emergency extracorporeal life support. Emergency extracorporeal life support should be considered early in cases of near-fatal intoxications with cardiodepressive drugs.

Orthotopic heart transplantation is definitive therapy for infants with failing staged palliation after univentricular repair. Although the surgical management of these patients may be quite straightforward, the actual cardiac and vascular anatomy is sometimes unpredictable. To overcome this problem, we developed a new technique to fabricate a custom made replica from 128-slice computed tomographic (CT) and magnetic resonance imaging (MRI) angiography to create a realistic model of the anatomic situation for preoperative assessment and intraoperative orientation in 2 patients with failed staged palliation. In such situations, solid replicas may be helpful in choosing surgical treatment strategies before heart transplantation, for intraoperative orientation, and in demonstrating the planned procedure to patients and parents with lifelike models.

Background The evidence of the advantageous physiology associated with right ventricle–to–pulmonary artery (RV–PA) shunt in the early postoperative period after the Norwood procedure for hypoplastic left heart syndrome has been recently widely reported. We investigated the late consequences of this modification from the perspective of the third-stage palliation, the Fontan operation. Methods Between September 1995 and November 2006, a consecutive series of 50 children with hypoplastic left heart syndrome from a single institution underwent a fenestrated Fontan operation (lateral tunnel technique): group 1 (n = 19) after the modified Blalock-Taussig shunt, and group 2 (n = 31) after RV–PA shunt during the Norwood procedure. Hemodynamic, echocardiographic, electrocardiographic, and clinical operative and perioperative data were analyzed. Results Children after the RV–PA shunt were characterized by higher preoperative partial oxygen tension in pulmonary arteries ( p = 0.018) and the aorta ( p = 0.028), as well as lower systolic, diastolic, and mean aortic pressure ( p = 0.005, p = 0.004, p = 0.019). After administration of 100% oxygen, this group additionally showed a lower value for systemic resistance ( p = 0.013). The analyzed angiograms revealed a higher incidence of systemic–to–pulmonary collateral vessels ( p = 0.003) in group 2. At the discharge after Fontan operation, children after the RV–PA shunt demonstrated higher arterial partial oxygen tension ( p = 0.004). The two groups did not differ significantly with respect to the mortality, ventricular function, incidence of pleural effusions or rhythm disturbances, intensive care unit stay, and hospitalization time. Conclusions The Norwood procedure with the RV–PA shunt provides satisfactory late hemodynamics. Children who underwent this method of palliation were more prone to the development of systemic–to–pulmonary arterial collaterals.

A 17-year-old girl without any cardiac symptoms and with no previous history of cardiovascular disease was diagnosed to have an intracardiac tumour. The diagnosis was made by chance during two-dimensional echocardiography which showed a mobile, peduncular tumour, 2 cm in diameter, arising from the apex of the left ventricle. The patient underwent successful surgery.

Neonates with severe left ventricular outflow tract obstruction (LVOTO) may have a competent left ventricle and mitral valve allowing for biventricular repair (BVR), which can be performed as a primary complete neonatal repair or as a staged procedure. The Norwood procedure, which is characterized by a right ventricle to pulmonary artery (RV-PA) shunt, significantly reduced mortality in this operation. We present our experience with a 2-staged BVR in two neonates with severe LVOTO, in whom we employed the modified Norwood operation (RV-PA shunt) for initial management.