Anisotropic distribution functions for spherical galaxies

A method is presented for finding anisotropic distribution functions for stellar systems with known, spherically symmetric, densities, which depends only on the two classical integrals of the energy and the magnitude of the angular momentum. It requires the density to be expressed as a sum of products of functions of the potential and of the radial coordinate. The solution corresponding to this type of density is in turn a sum of products of functions of the energy and of the magnitude of the angular momentum. The products of the density and its radial and transverse velocity dispersions can be also expressed as a sum of products of functions of the potential and of the radial coordinate. Several examples are given, including some of new anisotropic distribution functions. This device can be extended further to the related problem of finding two-integral distribution functions for axisymmetric galaxies.Comment: 5 figure

Dynamical modelling of the elliptical galaxy NGC 2974

In this paper we analyse the relations between a previously described oblate Jaffe model for an ellipsoidal galaxy and the observed quantities for NGC 2974, and obtain the length and velocity scales for a relevant elliptical galaxy model. We then derive the finite total mass of the model from these scales, and finally find a good fit of an isotropic oblate Jaffe model by using the Gauss-Hermite fit parameters and the observed ellipticity of the galaxy NGC 2974. The model is also used to predict the total luminous mass of NGC 2974, assuming that the influence of dark matter in this galaxy on the image, ellipticity and Gauss-Hermite fit parameters of this galaxy is negligible within the central region, of radius $0.5R_{\rm e}.$Comment: 7 figure

Galaxy Models with Tangentially Anisotropic Velocity Distributions

This paper provides two families of flexible and simple galaxy models. Representatives of many of the families possess the important cosmological cusps, with the density behaving like 1/r or 1/r^1.33 or 1/r^1.5 at small radii. The density falls off between 1/r^3 and 1/r^5 at large radii. We provide analytic and anisotropic distribution functions for all the models. Unlike many existing methods, our algorithm can yield tangentially anisotropic velocity dispersions in the outer parts, and so is useful for modeling populations of satellite galaxies and substructure in host galaxy halos. As an application, we demonstrate the degeneracy between mass and anisotropy for the satellite galaxy population of the Milky Way. This can introduce a factor of ~3 uncertainty in the mass of the Milky Way as inferred from the kinematics of the satellite population.Comment: to appear in AJ, extended appendix, typo corrected from the 2nd version (completely rewritten from the 1st version, see also astro-ph/0508419 for some materials split from the 1st version

A simplified biventricular defibrillator with fixed long detection intervals reduces implantable cardioverter defibrillator (ICD) interventions and heart failure hospitalizations in patients with non-ischaemic cardiomyopathy implanted for primary prevention: the RELEVANT [Role of long dEtection window programming in patients with LEft VentriculAr dysfunction, Non-ischemic eTiology in primary prevention treated with a biventricular ICD] study

To investigate the efficacy and safety of a cardiac resynchronization therapy with cardioverter-defibrillator (CRT-D) device with simplified ventricular tachycardia management in patients with non-ischaemic heart failure (HF) and primary prevention implantable cardioverter defibrillator (ICD) indication

Age of First Arrhythmic Event in Brugada Syndrome: Data From the SABRUS (Survey on Arrhythmic Events in Brugada Syndrome) in 678 Patients.

BACKGROUND: Data on the age at first arrhythmic event (AE) in Brugada syndrome are from limited patient cohorts. The aim of this study is 2-fold: (1) to define the age at first AE in a large cohort of patients with Brugada syndrome, and (2) to assess the influence of the mode of AE documentation, sex, and ethnicity on the age at first AE. METHODS AND RESULTS: A survey of 23 centers from 10 Western and 4 Asian countries gathered data from 678 patients with Brugada syndrome (91.3% men) with first AE documented at time of aborted cardiac arrest (group A, n=426) or after prophylactic implantable cardioverter-defibrillator implantation (group B, n=252). The vast majority (94.2%) of the patients were 16 to 70 years old at the time of AE, whereas pediatric (70 years) comprised 4.3% and 1.5%, respectively. Peak AE rate occurred between 38 and 48 years (mean, 41.9±14.8; range, 0.27-84 years). Group A patients were younger than in Group B by a mean of 6.7 years (46.1±13.2 versus 39.4±15.0 years; P<0.001). In adult patients (≥16 years), women experienced AE 6.5 years later than men (P=0.003). Whites and Asians exhibited their AE at the same median age (43 years). CONCLUSIONS: SABRUS (Survey on Arrhythmic Events in Brugada Syndrome) presents the first analysis on the age distribution of AE in Brugada syndrome, suggesting 2 age cutoffs (16 and 70 years) that might be important for decision-making. It also allows gaining insights on the influence of mode of arrhythmia documentation, patient sex, and ethnic origin on the age at AE

Profile of Brugada Syndrome Patients Presenting with Their First Documented Arrhythmic Event. Data from the Survey on Arrhythmic Events in BRUgada Syndrome (SABRUS).

BACKGROUND: Detailed information on the profile of Brugada syndrome (BrS) patients presenting their first arrhythmic event (AE) after prophylactic implantation of a cardioverter defibrillator (ICD) is limited. OBJECTIVES: 1) To compare clinical, electrocardiographic, electrophysiologic and genetic profiles of patients who exhibited their first documented AE as aborted cardiac arrest (CA) (group A) with those in whom the AE was documented after prophylactic ICD implantation (group B); 2) To characterize group B patients' profile using the Class II indications for ICD implantation established by HRS/EHRA/APHRS Expert Consensus Statement in 2013. METHODS: A survey of 23 centers from 10 Western and 4 Asian countries enabled data collection of 678 BrS patients with AE (group A, n=426; group B, n=252). RESULTS: First AE occurred in group B patients 6.7 years later than in group A (46.1+ 13.3 vs. 39.4+15.1, P<0.001). Group B patients had a higher incidence of family history of sudden cardiac death (SCD) and SCN5A mutations. Of the 252 group B patients, 189 (75%) complied with the HRS/EHRA/APHRS indications whereas the remaining 63 (25%) did not. CONCLUSION: BrS patients with first AE documented after prophylactic ICD implantation exhibited their AE at a later age with a higher incidence of positive family history of SCD and SCN5A mutations compared to those presenting with an aborted CA. Only 75% of patients who suffered an AE after receiving a prophylactic ICD complied with the 2013 Class II indications, suggesting efforts are still required for improving risk stratification

Gender Differences in Patients with Brugada Syndrome and Arrhythmic Events: Data from a Survey on Arrhythmic Events in 678 Patients.

BACKGROUND: There is limited information on gender differences in patients with Brugada syndrome (BrS) who experienced arrhythmic events (AEs). OBJECTIVES: To compare clinical, electrocardiographic (ECG), electrophysiologic (EP) and genetic characteristics between males and females in BrS-patients with their first AE. METHODS: The multicenter Survey on AE in BrS (SABRUS) collected data on first AE in 678 BrS-patients including 619 (91.3%) males and 59 (8.7%) females aged 0.27 to 84 (mean 42.5±14.1) years at the time of AE. RESULTS: After excluding pediatric patients, females were older than males (49.5±14.4 vs. 43±12.7 years, respectively, P=0.001). Higher proportions of females were observed in the pediatric and elderly populations. In Asians, male/female ratio of AE was ≈9-fold higher compared to Caucasians. Spontaneous type 1 BrS-ECG was associated with earlier onset of AE in pediatric females. A similar prevalence (≈65%) of spontaneous type 1 BrS-ECG was present in males and females above age of 60 years. Females less frequently showed a spontaneous type-1 BrS-ECG (31% vs. 59%, P<0.001) or arrhythmia-inducibility at EP study (34% vs. 64%, P<0.001). An SCN5A mutation was more frequently found in females (47.6% vs. 27.8% in males, P=0.007). CONCLUSIONS: This study confirms that female BrS-patients are much rarer, display less type 1 Brugada-ECG and exhibit lower inducibility rates than males. It shows for the first time that BrS females with AE have higher SCN5A mutation rates as well as the relationship between gender vs. age at onset of AE and ethnicity

Time-to-first appropriate shock in patients implanted prophylactically with an implantable cardioverter-defibrillator: data from the Survey on Arrhythmic Events in BRUgada Syndrome (SABRUS).

Aims: Data on predictors of time-to-first appropriate implantable cardioverter-defibrillator (ICD) therapy in patients with Brugada Syndrome (BrS) and prophylactically implanted ICD's are scarce. Methods and results: SABRUS (Survey on Arrhythmic Events in BRUgada Syndrome) is an international survey on 678 BrS patients who experienced arrhythmic event (AE) including 252 patients in whom AE occurred after prophylactic ICD implantation. Analysis was performed on time-to-first appropriate ICD discharge regarding patients' characteristics. Multivariate logistic regression models were utilized to identify which parameters predicted time to arrhythmia ≤5 years. The median time-to-first appropriate ICD therapy was 24.8 ± 2.8 months. A shorter time was observed in patients from Asian ethnicity (P < 0.05), those with syncope (P = 0.001), and those with Class IIa indication for ICD (P = 0.001). A longer time was associated with a positive family history of sudden cardiac death (P < 0.05). Multivariate Cox regression revealed shorter time-to-ICD therapy in patients with syncope [odds ratio (OR) 1.65, P = 0.001]. In 193 patients (76.6%), therapy was delivered during the first 5 years. Factors associated with this time were syncope (OR 0.36, P = 0.001), spontaneous Type 1 Brugada electrocardiogram (ECG) (OR 0.5, P < 0.05), and Class IIa indication (OR 0.38, P < 0.01) as opposed to Class IIb (OR 2.41, P < 0.01). A near-significant trend for female gender was also noted (OR 0.13, P = 0.052). Two score models for prediction of <5 years to shock were built. Conclusion: First appropriate therapy in BrS patients with prophylactic ICD's occurred during the first 5 years in 76.6% of patients. Syncope and spontaneous Type 1 Brugada ECG correlated with a shorter time to ICD therapy

Fever-related arrhythmic events in the multicenter Survey on Arrhythmic Events in Brugada Syndrome

BACKGROUND: The literature on fever related arrhythmic events (AE) in Brugada syndrome (BrS) is currently limited to few case reports and small series. OBJECTIVE: The current study aims to describe the characteristics of fever-related AE in a large cohort of BrS patients. METHODS: SABRUS is a multicenter study on 678 BrS patients with first AE documented at time of aborted cardiac arrest (ACA) (n=426) or after prophylactic ICD implantation (n=252). RESULTS: In 35(6%) of the 588 patients with available information, the AE occurred during a febrile illness. Most of the 35 patients were male (80%), Caucasian (83%) and proband (70%). Age at time of AE was 29±24 (range 0.3-76) years. Most patients (80%) presented with ACA and 6 (17%) with arrhythmic storm. Family history of sudden death, history of syncope and spontaneous type 1 Brugada-ECG were noted in 17%, 40% and 66% of patients, respectively. VF was induced at EPS in 9/19(47%) patients. An SCN5A mutation was found in 14/28(50%) patients. The highest proportion of fever-related AE was observed in the pediatric population (age <16), with disproportionally higher event rate in the very young (0-5 years old) (65%). Males were involved in all age groups and females only in the pediatric and elderly groups. Fever-related AE affected 17 Caucasians aged<24 years, but no Asians aged <24 years. CONCLUSIONS: The risk of fever-related AE in BrS markedly varies according to age group, gender and ethnicity. Taking these factors into account could help the clinical management of BrS patients with fever