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1.
Artigo em Inglês | MEDLINE | ID: mdl-29897627

RESUMO

BACKGROUND: Currently, several geographies around the world remain underrepresented in medical device trials. The PANORAMA 2 study was designed to assess contemporary region-specific differences in clinical practice patterns of patients with cardiac implantable electronic devices (CIEDs). METHODS: In this prospective, multicenter, observational, multinational study, baseline and implant data of 4,706 patients receiving Medtronic CIEDs (Medtronic plc, Minneapolis, MN, USA; either de novo device implants, replacements, or upgrades) were analyzed, consisting of: 54% implantable pulse generators (IPGs), 20.3% implantable cardiac defibrillators (ICDs), 15% cardiac resynchronization therapy -defibrillators, and 5.1% cardiac resynchronization therapy -pacemakers, from 117 hospitals in 23 countries across four geographical regions between 2012 and 2016. RESULTS: For all device types, in all regions, there were fewer females than males enrolled, and women were less likely to have ischemic cardiomyopathy. Implant procedure duration differed significantly across the geographies for all device types. Subjects from emerging countries, women, and older patients were less likely to receive a magnetic resonance imaging-compatible device. Defibrillation testing differed significantly between the regions. European patients had the highest rates of atrial fibrillation (AF), and the lowest number of implanted single-chamber IPGs. Evaluation of stroke history suggested that the general embolic risk is more strongly associated with stroke than AF. CONCLUSIONS: We provide comprehensive descriptive data on patients receiving Medtronic CIEDs from several geographies, some of which are understudied in randomized controlled trials. We found significant variations in patient characteristics. Several medical decisions appear to be affected by socioeconomic factors. Long-term follow-up data will help evaluate if these variations require adjustments to outcome expectations.

2.
Pacing Clin Electrophysiol ; 39(8): 805-13, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27226200

RESUMO

BACKGROUND: Atrial fibrillation (AF) is an arrhythmia that can be difficult to identify and classify with short-term monitoring. However, current standard of practice requires only short-term monitoring to determine AF classifications and identify symptom-arrhythmia correlations prior to AF ablation procedures. Insertable cardiac monitors (ICMs) offer continuous arrhythmia monitoring, which could lead to a more accurate measurement of AF burden than standard of practice. METHODS: This analysis focused on 121 patients enrolled in the LINQ Usability Study indicated for an AF ablation. Patients were followed for up to 1 year after ICM insertion. Clinical AF classifications were made by physicians prior to ICM implantation based on available clinical information. Device-detected AF burden and maximum daily burden were collected from device interrogations and remote transmissions. Device AF classifications were determined by categorizing the AF burden based on guidelines. RESULTS: Agreement between clinical and device AF classifications preablation was poor (48.3%, N = 58). The strongest agreement was in the paroxysmal AF group but still was only 61.8%. Furthermore, device-detected preablation AF burden led to the decision to defer AF ablation procedures in 16 (13.2%) patients. The median AF burden in patients with ≥6 months follow-up postablation (n = 71) was reduced from 7.8% (interquartile range [IQR]: 0-32.1%) to 0% (IQR: 0-0.7%). CONCLUSIONS: ICM monitoring to determine AF burden pre- and post-AF ablation may have clinical utility for management of ablation candidates through more accurate AF classification and guiding treatment decisions.


Assuntos
Fibrilação Atrial/diagnóstico , Fibrilação Atrial/cirurgia , Eletrocardiografia Ambulatorial/instrumentação , Eletrocardiografia Ambulatorial/métodos , Próteses e Implantes , Ablação por Cateter , Determinação de Ponto Final , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Recidiva , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Resultado do Tratamento
3.
Heart Rhythm ; 13(7): 1425-30, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26961298

RESUMO

BACKGROUND: For clinicians, confidence in atrial fibrillation (AF) episode classification is an important consideration when electing to use insertable cardiac monitors (ICMs). OBJECTIVE: The purpose of this study was to report on the improved AF detection algorithm in the Reveal LINQ ICM. METHODS: The Reveal LINQ Usability Study is a nonrandomized, prospective, multicenter trial. The ICM has been miniaturized, uses wireless telemetry for remote patient monitoring, and its AF algorithm includes a new p-wave filter. At 1 month post-device insertion, Holter monitor data were collected and annotated for true AF episodes ≥2 minutes, and performance metrics were evaluated by comparing Holter annotations with ICM detections. RESULTS: The study enrolled 151 patients (age 56.6 ± 12.1, male 67%). Reasons for monitoring included AF ablation or AF management in 81.5% (n = 123), syncope in 12.6% (n = 19), and other indications in 5.9% (n = 9) of patients. Of the 138 patients with an analyzable Holter recording, a total of 112 true AF episodes were identified in 38 patients (27.5%). The overall accuracy of the ICM to detect durations of AF or non-AF episodes was 99.4%, and the AF burden measured by the ICM was highly correlated with the Holter (Pearson coefficient 0.995). CONCLUSION: The new AF detection algorithm in the Reveal LINQ ICM accurately detects the presence or absence of AF. Additionally, it showed high sensitivity in detecting AF duration in patients with a history of intermittent and symptomatic AF.


Assuntos
Fibrilação Atrial/diagnóstico , Eletrocardiografia Ambulatorial , Adulto , Idoso , Algoritmos , Eletrocardiografia Ambulatorial/instrumentação , Eletrocardiografia Ambulatorial/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miniaturização/métodos , Monitorização Ambulatorial/instrumentação , Monitorização Ambulatorial/métodos , Estudos Prospectivos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
4.
PLoS One ; 8(10): e77720, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24147066

RESUMO

Complex human diseases commonly differ in their phenotypic characteristics, e.g., Crohn's disease (CD) patients are heterogeneous with regard to disease location and disease extent. The genetic susceptibility to Crohn's disease is widely acknowledged and has been demonstrated by identification of over 100 CD associated genetic loci. However, relating CD subphenotypes to disease susceptible loci has proven to be a difficult task. In this paper we discuss the use of cluster analysis on genetic markers to identify genetic-based subgroups while taking into account possible confounding by population stratification. We show that it is highly relevant to consider the confounding nature of population stratification in order to avoid that detected clusters are strongly related to population groups instead of disease-specific groups. Therefore, we explain the use of principal components to correct for population stratification while clustering affected individuals into genetic-based subgroups. The principal components are obtained using 30 ancestry informative markers (AIM), and the first two PCs are determined to discriminate between continental origins of the affected individuals. Genotypes on 51 CD associated single nucleotide polymorphisms (SNPs) are used to perform latent class analysis, hierarchical and Partitioning Around Medoids (PAM) cluster analysis within a sample of affected individuals with and without the use of principal components to adjust for population stratification. It is seen that without correction for population stratification clusters seem to be influenced by population stratification while with correction clusters are unrelated to continental origin of individuals.


Assuntos
Doença de Crohn/epidemiologia , Doença de Crohn/genética , Adolescente , Adulto , Análise por Conglomerados , Doença de Crohn/classificação , Feminino , Predisposição Genética para Doença/genética , Genótipo , Humanos , Masculino , Polimorfismo de Nucleotídeo Único/genética , Análise de Componente Principal , Adulto Jovem
5.
Hum Genet ; 131(10): 1591-613, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22760307

RESUMO

The interest in performing gene-environment interaction studies has seen a significant increase with the increase of advanced molecular genetics techniques. Practically, it became possible to investigate the role of environmental factors in disease risk and hence to investigate their role as genetic effect modifiers. The understanding that genetics is important in the uptake and metabolism of toxic substances is an example of how genetic profiles can modify important environmental risk factors to disease. Several rationales exist to set up gene-environment interaction studies and the technical challenges related to these studies-when the number of environmental or genetic risk factors is relatively small-has been described before. In the post-genomic era, it is now possible to study thousands of genes and their interaction with the environment. This brings along a whole range of new challenges and opportunities. Despite a continuing effort in developing efficient methods and optimal bioinformatics infrastructures to deal with the available wealth of data, the challenge remains how to best present and analyze genome-wide environmental interaction (GWEI) studies involving multiple genetic and environmental factors. Since GWEIs are performed at the intersection of statistical genetics, bioinformatics and epidemiology, usually similar problems need to be dealt with as for genome-wide association gene-gene interaction studies. However, additional complexities need to be considered which are typical for large-scale epidemiological studies, but are also related to "joining" two heterogeneous types of data in explaining complex disease trait variation or for prediction purposes.


Assuntos
Meio Ambiente , Interação Gene-Ambiente , Estudo de Associação Genômica Ampla , Genoma , Animais , Predisposição Genética para Doença , Humanos , Modelos Estatísticos
6.
J Allergy Clin Immunol ; 130(2): 376-81.e8, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22738677

RESUMO

BACKGROUND: The role of IgE in patients with severe asthma is not fully understood. OBJECTIVE: We sought to investigate whether IgE to Staphylococcus aureus enterotoxins might be relevant to disease severity in adult asthmatic patients. METHODS: Specific IgE antibody concentrations in serum against enterotoxins, grass pollen (GP), and house dust mite allergens and total IgE levels were measured in adult cohorts of 69 control subjects, 152 patients with nonsevere asthma, and 166 patients with severe asthma. Severe asthma was defined as inadequately controlled disease despite high-dose inhaled corticosteroids plus at least 2 other controller therapies, including oral steroids. RESULTS: Enterotoxin IgE positivity was significantly greater in patients with severe asthma (59.6%) than in healthy control subjects (13%, P< .001). Twenty-one percent of patients with severe asthma with enterotoxin IgE were considered nonatopic. Logistic regression analyses demonstrated significantly increased risks for enterotoxin IgE-positive subjects to have any asthma (OR, 7.25; 95% CI, 2.7-19.1) or severe asthma (OR, 11.09; 95% CI, 4.1-29.6) versus enterotoxin IgE-negative subjects. The presence of GP or house dust mite IgE antibodies was not associated with either significantly increased risk for asthma or severity. Oral steroid use and hospitalizations were significantly increased in patients with enterotoxin IgE and nonatopic asthma. GP IgE was associated with a higher FEV(1) percent predicted value, and enterotoxin IgE was associated with a lower FEV(1) percent predicted value. CONCLUSIONS: Staphylococcal enterotoxin IgE antibodies, but not IgE against inhalant allergens, are risk factors for asthma severity. We hypothesize that the presence of enterotoxin IgE in serum indicates the involvement of staphylococcal superantigens in the pathophysiology of patients with severe asthma.


Assuntos
Anticorpos Antibacterianos/imunologia , Asma/imunologia , Enterotoxinas/imunologia , Imunoglobulina E/imunologia , Infecções Estafilocócicas/imunologia , Staphylococcus aureus/imunologia , Corticosteroides/administração & dosagem , Corticosteroides/uso terapêutico , Adulto , Alérgenos/imunologia , Animais , Antiasmáticos/administração & dosagem , Antiasmáticos/uso terapêutico , Anticorpos Antibacterianos/sangue , Asma/complicações , Asma/tratamento farmacológico , Asma/virologia , Estudos de Casos e Controles , Feminino , Humanos , Imunoglobulina E/sangue , Masculino , Pessoa de Meia-Idade , Pólen/imunologia , Pyroglyphidae/imunologia , Fatores de Risco , Índice de Gravidade de Doença , Infecções Estafilocócicas/complicações , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Superantígenos/sangue , Superantígenos/imunologia
7.
Hum Brain Mapp ; 33(6): 1253-67, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21567658

RESUMO

Subject-specific hemodynamic response functions (HRFs) have been recommended to capture variation in the form of the hemodynamic response between subjects (Aguirre et al., [ 1998]: Neuroimage 8:360-369). The purpose of this article is to find optimal designs for estimation of subject-specific parameters for the double gamma HRF. As the double gamma function is a nonlinear function of its parameters, optimal design theory for nonlinear models is employed in this article. The double gamma function is linearized by a Taylor approximation and the maximin criterion is used to handle dependency of the D-optimal design on the expansion point of the Taylor approximation. A realistic range of double gamma HRF parameters is used for the expansion point of the Taylor approximation. Furthermore, a genetic algorithm (GA) (Kao et al., [ 2009]: Neuroimage 44:849-856) is applied to find locally optimal designs for the different expansion points and the maximin design chosen from the locally optimal designs is compared to maximin designs obtained by m-sequences, blocked designs, designs with constant interstimulus interval (ISI) and random event-related designs. The maximin design obtained by the GA is most efficient. Random event-related designs chosen from several generated designs and m-sequences have a high efficiency, while blocked designs and designs with a constant ISI have a low efficiency compared to the maximin GA design.


Assuntos
Circulação Cerebrovascular/fisiologia , Hemodinâmica/fisiologia , Imagem por Ressonância Magnética/métodos , Algoritmos , Simulação por Computador , Humanos , Processamento de Imagem Assistida por Computador , Dinâmica não Linear
8.
Neuroimage ; 56(3): 1338-52, 2011 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-21406234

RESUMO

The design of a multi-subject fMRI experiment needs specification of the number of subjects and scanning time per subject. For example, for a blocked design with conditions A or B, fixed block length and block order ABN, where N denotes a null block, the optimal number of cycles of ABN and the optimal number of subjects have to be determined. This paper presents a method to determine the optimal number of subjects and optimal number of cycles for a blocked design based on the A-optimality criterion and a linear cost function by which the number of cycles and the number of subjects are restricted. Estimation of individual stimulus effects and estimation of contrasts between stimulus effects are both considered. The mixed-effects model is applied and analytical results for the A-optimal number of subjects and A-optimal number of cycles are obtained under the assumption of uncorrelated errors. For correlated errors with a first-order autoregressive (AR1) error structure, numerical results are presented. Our results show how the optimal number of cycles and subjects depend on the within- to between-subject variance ratio. Our method is a new approach to determine the optimal scanning time and optimal number of subjects for a multi-subject fMRI experiment. In contrast to previous results based on power analyses, the optimal number of cycles and subjects can be described analytically and costs are considered.


Assuntos
Imagem por Ressonância Magnética/métodos , Projetos de Pesquisa , Algoritmos , Orçamentos , Interpretação Estatística de Dados , Hemodinâmica/fisiologia , Humanos , Análise dos Mínimos Quadrados , Modelos Lineares , Imagem por Ressonância Magnética/economia , Imagem por Ressonância Magnética/estatística & dados numéricos , Pesquisa/economia , Tamanho da Amostra
9.
Neuroimage ; 49(3): 2433-43, 2010 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-19833212

RESUMO

In this paper we apply the genetic algorithm developed by Kao et al. (2009) to find designs which are robust against misspecification of the error autocorrelation. Two common optimality criteria, the A-optimality criterion and the D-optimality criterion, based upon a general linear model are employed to obtain locally optimal designs for a given value of the autocorrelation. The maximin criterion is then used to obtain designs which are robust against misspecification of the autocorrelation. Furthermore, robustness depending on the choice of optimality criterion is evaluated. We show analytically and empirically that the A- and D-optimality criterion will result in different optimal designs, e.g. with different stimulus frequencies. Optimal stimulus frequency for the A-optimality criterion has been derived by Liu et al. (2004) whereas we derive here the optimal stimulus frequency for the D-optimality criterion. Conclusions about the robustness of an optimal design against misspecification of model parameters and choice of optimality criterion are drawn based upon our results.


Assuntos
Algoritmos , Imagem por Ressonância Magnética , Modelos Teóricos , Simulação por Computador
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