Automatically Segmenting the Left Atrium from Cardiac Images Using Successive 3D U-Nets and a Contour Loss

International audienceRadiological imaging offers effective measurement of anatomy, which is useful in disease diagnosis and assessment. Previous study has shown that the left atrial wall remodeling can provide information to predict treatment outcome in atrial fibrillation. Nevertheless, the segmentation of the left atrial structures from medical images is still very time-consuming. Current advances in neural network may help creating automatic segmentation models that reduce the workload for clinicians. In this preliminary study, we propose automated, two-stage, three-dimensional U-Nets with convolutional neural network, for the challenging task of left atrial segmentation. Unlike previous two-dimensional image segmentation methods, we use 3D U-Nets to obtain the heart cavity directly in 3D. The dual 3D U-Net structure consists of, a first U-Net to coarsely segment and locate the left atrium, and a second U-Net to accurately segment the left atrium under higher resolution. In addition, we introduce a Contour loss based on additional distance information to adjust the final segmentation. We randomly split the data into training datasets (80 subjects) and validation datasets (20 subjects) to train multiple models, with different augmentation setting. Experiments show that the average Dice coefficients for validation datasets are around 0.91 - 0.92, the sensitivity around 0.90-0.94 and the specificity 0.99. Compared with traditional Dice loss, models trained with Contour loss in general offer smaller Hausdorff distance with similar Dice coefficient, and have less connected components in predictions. Finally, we integrate several trained models in an ensemble prediction to segment testing datasets

Association between atrial fibrillation and <i>Helicobacter pylori</i>

The connection between atrial fibrillation (AF) and H. pylori (HP) infection is still matter of debate. We performed a systematic review and metanalysis of studies reporting the association between AF and HF. A systematic review of all available reports in literature of the incidence of HP infection in AF and comparing this incidence with subjects without AF were analysed. Risk ratio and 95% confidence interval (CI) and risk difference with standard error (SE) were the main statistics indexes. Six retrospective studies including a total of 2921 were included at the end of the selection process. Nine hundred-fifty-six patients (32.7%) were in AF, whereas 1965 (67.3%) were in normal sinus rhythm (NSR). Overall, 335 of 956 patients with AF were HP positive (35%), whereas 621 were HP negative (65%). In addition, 643 of 1965 NSR patients (32.7%) were HP positive while 1,322 were negative (67.3%; Chi-square 2.15, p = 0.21). The Cumulative Risk Ratio for AF patients for developing an HP infection was 1.19 (95% CI 1.08–1.41). In addition, a small difference risk towards AF was found (0.11 [SE = 0.04]). Moreover, neither RR nor risk difference were influenced by the geographic area at meta-regression analysis. Finally, there was a weak correlation between AF and HP (coefficient = 0.04 [95% CI −0.01–0.08]). We failed to find any significant correlation between H. pylori infection and AF and, based on our data, it seems unlikely than HP can be considered a risk factor for AF. Further larger research is warranted

Prevalence of different comorbidities in COPD patients by gender and GOLD stage

BACKGROUND: Several comorbidities frequently affect COPD progression. Aim of the study was to assess the prevalence of main comorbidities by gender and disease severity in a cohort of COPD patients referring for the first time to a specialist institution. METHODS: The study was a non-interventional, cross-sectional investigation carried out via automatic and anonymous selection from the institutional data base over the period 2012–2015. Inclusion criteria were: subjects of both sex aged ≥40 years; diagnosis of COPD according to GOLD guidelines 2014; the availability of a complete clinical record file. Variables collected were: lung function; smoking history; BMI; the Charlson Comorbidity Index (CCI); number and kind of comorbidities for each patient. RESULTS: At least one comorbidity of clinical relevance was found in 78.6 % of patients, but at least two in 68.8 %, and three or more were found in 47.9 % of subjects. Mean CCI was 3.4 ± 1.6sd. The overall prevalence was 2.6 comorbidities per patient, but 2.5 in males, and 3.0 in females, respectively (p < 0.05). Cardio-vascular disorders were the most frequent, but significantly more frequent in males (44.7 vs 30.7 %, respectively), while the metabolic, the digestive and the osteo-articular disorders were prevailing in females (12.4 vs 9.2; 14.2 vs 4.8, and 6.0 vs 3.8, respectively). In particular, chronic cor pumonale and arrhythmias mainly prevailed in men and congestive heart failure in females, while arterial hypertension resulted equally distributed. As concerning respiratory disorders, pneumonia, pleural effusions and chronic respiratory failure were more frequently found in men, while bronchiectasis and asthma-COPD overlap syndrome (ACOS) in females. Anaemia, gall bladder stones, osteoporosis and spontaneous fractures mostly prevailed in females, while gastric disorders of inflammatory origin and arthrosis were more frequent in males. Cognition disorders, dementia and signs of degenerative brain disorders were more frequently found in men, while depression in females. Finally, lung cancer was at the first place in men, but at the second in females. CONCLUSIONS: All comorbidities increased their prevalence progressively up to the last stage of COPD severity, except the cardio-vascular and the metabolic ones which dropped in the IV GOLD stage, presumably due to the high mortality rate in this severe COPD stage. The gender-dependency of comorbidities was confirmed in general terms, even if lung cancer proved a dramatic increase almost independently of sex

Novel Echocardiographic Biomarkers in the Management of Atrial Fibrillation

Purpose of Review: Atrial fibrillation (AF) is the most common arrhythmia in adults. The number of patients with AF is anticipated to increase annually, mainly due to the aging population alongside improved arrhythmia detection. AF is associated with a significantly elevated risk of hospitalization, stroke, thromboembolism, heart failure, and all-cause mortality. Echocardiography is one of the key components of routine assessment and management of AF. Therefore, the aim of this review is to briefly summarize current knowledge on “novel” echocardiographic parameters that may be of value in the management of AF patients. Recent Findings: Novel echocardiographic biomarkers and their clinical application related to the management of AF have been taken into consideration. Both standard parameters such as atrial size and volume but also novels like atrial strain and tissue Doppler techniques have been analyzed. Summary: A number of novel echocardiographic parameters have been proven to enable early detection of left atrial dysfunction along with increased diagnosis accuracy. This concerns particularly experienced echocardiographers. Hence, these techniques might improve the prediction of stroke and thromboembolic events among AF patients and need to be further developed and disseminated. Nonetheless, even the standard imaging parameters could be of significant value and should not be discontinued in everyday clinical practice. © 2019, The Author(s)

Atrial fibrillation in immigrant groups::a cohort study of all adults 45 years of age and older in Sweden

To study the association between country of birth and incident atrial fibrillation (AF) in several immigrant groups in Sweden. The study population included all adults (n = 3,226,752) aged 45 years and older in Sweden. AF was defined as having at least one registered diagnosis of AF in the National Patient Register. The incidence of AF in different immigrant groups, using Swedish-born as referents, was assessed by Cox regression, expressed in hazard ratios (HRs) and 95% confidence intervals (CI). All models were stratified by sex and adjusted for age, geographical residence in Sweden, educational level, marital status, and neighbourhood socioeconomic status. Compared to their Swedish-born counterparts, higher incidence of AF [HR (95% CI)] was observed among men from Bosnia 1.74 (1.56-1.94) and Latvia 1.29 (1.09-1.54), and among women from Iraq 1.96 (1.67-2.31), Bosnia 1.88 (1.61-1.94), Finland 1.14 (1.11-1.17), Estonia 1.14 (1.05-1.24) and Germany 1.08 (1.03-1.14). Lower incidence of AF was noted among men (HRs ≤ 0.60) from Iceland, Southern Europe (especially Greece, Italy and Spain), Latin America (especially Chile), Africa, Asia (including Iraq, Turkey, Lebanon and Iran), and among women from Nordic countries (except Finland), Southern Europe, Western Europe (except Germany), Africa, North America, Latin America, Iran, Lebanon and other Asian countries (except Turkey and Iraq). In conclusion, we observed substantial differences in incidence of AF between immigrant groups and the Swedish-born population. A greater awareness of the increased risk of AF development in some immigrant groups may enable for a timely diagnosis, treatment and prevention of its debilitating complications, such as stroke

Epidemiology of atrial fibrillation: European perspective

Massimo Zoni-Berisso, Fabrizio Lercari, Tiziana Carazza, Stefano DomenicucciDepartment of Cardiology, ASL 3, Padre A Micone Hospital, Genoa, ItalyAbstract: In the last 20 years, atrial fibrillation (AF) has become one of the most important public health problems and a significant cause of increasing health care costs in western countries. The prevalence of AF is increasing due to our greater ability to treat chronic cardiac and noncardiac diseases, and the improved ability to suspect and diagnose AF. At the present time, the prevalence of AF (2%) is double that reported in the last decade. The prevalence of AF varies with age and sex. AF is present in 0.12%&ndash;0.16% of those younger than 49 years, in 3.7%&ndash;4.2% of those aged 60&ndash;70 years, and in 10%&ndash;17% of those aged 80 years or older. In addition, it occurs more frequently in males, with a male to female ratio of 1.2:1. The incidence of AF ranges between 0.21 and 0.41 per 1,000 person/years. Permanent AF occurs in approximately 50% of patients, and paroxysmal and persistent AF in 25% each. AF is frequently associated with cardiac disease and comorbidities. The most common concomitant diseases are coronary artery disease, valvular heart disease, and cardiomyopathy. The most common comorbidities are hypertension, diabetes, heart failure, chronic obstructive pulmonary disease, renal failure, stroke, and cognitive disturbance. Paroxysmal AF occurs in younger patients and with a reduced burden of both cardiac disease and comorbidities. Generally, the history of AF is long, burdened by frequent recurrences, and associated with symptoms (in two thirds of patients). Patients with AF have a five-fold and two-fold higher risk of stroke and death, respectively. We estimate that the number of patients with AF in 2030 in Europe will be 14&ndash;17 million and the number of new cases of AF per year at 120,000&ndash;215,000. Given that AF is associated with significant morbidity and mortality, this increasing number of individuals with AF will have major public health implications.Keywords: atrial fibrillation, epidemiology, risk factors, mortality, strok