The "Defibrillation Testing, Why Not?" survey. Testing of subcutaneous and transvenous defibrillators in the Italian clinical practice

Background: Defibrillation testing (DT) can be omitted in patients undergoing transvenous implantable cardioverter-defibrillator (T-ICD) implantation, but it is still recommended for patients at risk for a high defibrillation threshold and for ICD generator changes. Moreover, DT is still recommended on implantation of subcutaneous ICD (S-ICD). The aim of the present survey was to analyze the current practice of DT during T-ICD and S-ICD implantations.Methods: In March 2021, an ad hoc questionnaire on the current performance of DT and the standard practice adopted during testing was completed at 72 Italian centers implanting S-ICD and T-ICD.Results: 48 (67%) operators reported never performing DT during de-novo T-ICD implantations, while no operators perform it systematically. The remaining respondents perform it for patients at risk for a high defibrillation threshold. DT is never performed at T-ICD generator change. At the time of de-novo S-ICD implantation, DT is never performed by 9 (13%) operators and performed systematically by 48 (66%). The remaining operators frequently omit DT in patients with more severe systolic dysfunction. DT is not performed at S-ICD generator change by 92% of operators. DT is conducted by delivering a first shock energy of 65 J by 60% of operators, while the remaining 40% test lower energy values.Conclusions: In current clinical practice, most operators omit DT at T-ICD implantation, even when still recommended in the guidelines. DT is also frequently omitted at S-ICD implantation, and a wide variability exists among operators in the procedures followed during DT

Network-Aware Availability Modeling of an End-to-End NFV-Enabled Service

Network Function Virtualization (NFV) represents a key shift in nowadays network service provisioning by entailing higher flexibility, elasticity, and programmability of network services. Dependability is one of the main aspects that need to be investigated and tackled in order to profitably use NFV in the future. The main objective of this paper is to propose a comprehensive approach to estimate the end-to-end NFV-deployed service availability and present a quantitative assessment of the network factors that affect the availability of the service provided by an NFV architecture. To achieve this goal, we adopted a two-level availability model where i) the low level considers the network topology structure and NFV connectivity requirements through the definition of the system structure function based on minimal-cut sets and ii) the higher level examines dynamics and failure modes of network and NFV elements through stochastic activity networks. By using the proposed model, we have carried out an extensive sensitivity analysis to identify the impact on the service availability of the different service elements involved in the delivery, and their deployment across the network. The results highlight the significant impact that network nodes have on the end-to-end network service. Less robust network nodes may reduce the availability of an NFV-enabled service by more than one order of magnitude even though NFV elements like VNFs or MANO are provided with redundancy. Moreover, the results show that adopting an SDN-integrated network degrades the service availability and increases the vulnerability of the network service to SDN controllers unless adequately protected

Modeling and Evaluating NFV-Enabled Network Services under Different Availability Modes

Network and Telecom operators are continuously embracing the adoption of Network Function Virtualization (NFV) as a means to provide more agile, flexible and cost-efficient services. Many telecommunication services need to possess carrier-grade quality of service; therefore, future NFV-enabled telecom services should present high levels of availability. In this paper, we present a composed availability model of NFV-enabled network services under different availability modes, namely Standard Availability, Cold Protection, and Hot Protection. We model and analyze the availability of NFV-enabled network services for each of the availability modes aiming at finding the best redundancy configuration to ensure carrier-grade quality. Through discrete-event simulation analysis we are able to identify the most suitable redundancy configuration for each of the availability modes.acceptedVersio

MR Imaging in the Evaluation of Placental Abruption: Correlation with Sonographic Findings

To evaluate the accuracy of magnetic resonance (MR) imaging and color Doppler ultrasonography (US) in the diagnosis of abruption, to assess the accuracy of the different MR imaging sequences in the visualization of clots, and to evaluate the correlation between MR imaging findings and clinical outcome. This study protocol was approved by the institutional review board, and written informed consent was obtained from all patients. Between March 2008 and June 2010, 60 consecutive patients (mean gestational age, 30.7 weeks [range, 27-38 weeks]; mean age, 29 years [range, 20-38 years]) who were referred for US and MR imaging owing to a putative diagnosis of abruption were assessed. Multiplanar half-Fourier rapid acquisition with relaxation enhancement, true fast imaging with steady-state precession, three-dimensional T1-weighted gradient-echo MR imaging, and sagittal diffusion-weighted MR imaging were performed. Two radiologists independently reviewed each case, resolving by consensus any diagnostic discrepancy. During a second imaging analysis, the same readers randomly and independently assessed the single sequences. The signal intensity of hematoma was correlated with clinical outcome. The reference standard for abruption was the presence of clots and/or fibrin at inspection of the placenta after delivery. The diagnostic efficacy of US and MR imaging was calculated with 95% confidence intervals. Interobserver agreement was assessed by using the Cohen κ test. The performance of US and MR imaging was calculated in 39 patients who gave birth less than 10 days after MR imaging; these women were considered to have an adequate reference standard. Abruption was found at delivery in 19 patients. Abruption was identified in 10 of the 19 patients (52%) with US and in all 19 (100%) with MR imaging (P = .002), with an interobserver agreement of 0.949. Diffusion- and T1-weighted sequences helped identify 19 (100%) and 18 (95%) of the 19 abruptions, respectively; interrater agreement was very good for all sequences (κ = 0.892-1.0). Hematomas classified as hyperacute or acute worsened to abruption grade II, with the mother being symptomatic or the fetus distressed. MR imaging can accurately depict placental abruption, with excellent interobserver agreement, and should be considered after negative US findings in the presence of late pregnancy bleeding if the diagnosis of abruption would change management. © RSNA, 2011

Opportunities and drawbacks of the subcutaneous defibrillator across different clinical settings

IntroductionThe subcutaneous implantable cardioverter-defibrillator (S-ICD) is an established therapy for the prevention of sudden cardiac death (SCD) and an alternative to a transvenous implantable cardioverter-defibrillator system in selected patients. Beyond randomized clinical trials, many observational studies have described the clinical performance of S-ICD across different subgroups of patients.Areas coveredOur review aimed to describe the opportunities and drawbacks of the S-ICD, focusing on their use in special populations and across different clinical settings.Expert opinionThe choice to implant S-ICD should be based on the patient's tailored approach, which takes into account the adequate S-ICD screening at rest or during stress, the infective risk, the ventricular arrhythmia susceptibility, the progressive nature of the underlying disease, the work or sports activity, and the risk of lead-related complications

Celiac disease. Evaluation with dynamic contrast-enhanced MR imaging

Purpose: To prospectively determine mural perfusion dynamics in patients with untreated celiac disease by using dynamic contrast material-enhanced magnetic resonance (MR) imaging and to compare these dynamics with those in a control population and in patients with celiac disease treated with a gluten-free diet. Materials and Methods: Institutional review board approval and informed consent from all participants were obtained. Sixty consecutive patients with untreated celiac disease, 45 patients with celiac disease treated with a gluten-free diet for at least 1 year, and 30 control subjects were enrolled in this study. Dynamic contrast-enhanced MR imaging was performed by using a 1.5-T MR unit. For each MR imaging examination, maximum enhancement, slope of enhancement, and time-signal intensity curves were calculated at the level of the descending duodenal wall. Duodenal wall thickness was also evaluated. Statistical evaluation was performed by using one-way analysis of variance, and the results were confirmed by using the Bartlett test for equal variances and complemented by using Bonferroni multiple comparison, linear correlation, and the Student t test for paired data. Results: Mean maximum enhancement of the duodenal wall was significantly higher in patients with untreated celiac disease (229.1 +/- 46.4 [standard deviation]) than in patients with treated celiac disease (109.8 +/- 27.8) and control subjects (94.7 +/- 17.9) (P < .001 for each comparison). All 60 untreated patients showed a curve characterized by fast enhancement and washout (type 4), while all 45 treated patients and the 30 control subjects showed a curve characterized by slow constant enhancement (type 2). Mean duodenal wall thickness was not significantly different between untreated patients (2.2 mm +/- 0.4), treated patients (2.0 mm +/- 0.3), and control subjects (2.0 mm +/- 0.4) (one-way analysis of variance, P = .4177; Bartlett test, P = .6951). Conclusion: The results of this study suggest that dynamic evaluation of the bowel wall by using contrast-enhanced MR imaging can be an effective and reproducible way to show the inflammation state in celiac disease

[2019 Catheter Ablation Registry of the Italian Association of Arrhythmology and Cardiac Pacing]

Background: This report describes the findings of the 2019 Italian Catheter Ablation Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC). Methods: Data collection was retrospective. A standardized questionnaire was completed by each of the participating centers. Results: A total of 15 201 ablation procedures were performed by 91 institutions. Most (78%) of the centers has one electrophysiology laboratory, and 17% of them has a hybrid cardiac surgery laboratory. Almost all (98%) centers have a 3D mapping system. The median number of electrophysiologists and nurses involved in the electrophysiology laboratory was 3 and an electrophysiology technician was involved in 30% of all centers. In 88.4% of cases, ablations were performed for supraventricular arrhythmias, and among these the most frequently treated arrhythmia was atrial fibrillation (32.9%), followed by atrioventricular nodal reentrant tachycardia (23.9%), and common atrial flutter (11.7%). In 10 256 (67.4%) patients catheter ablation was performed by means of a 3D mapping system, with a "near-zero" fluoroscopic approach in 4626 (30.4%) of all patients. Conclusions: The 2019 Italian Catheter Ablation Registry confirmed that atrial fibrillation is the most commonly treated arrhythmia in the ablation centers with an increasing number of procedures performed with a 3D mapping system and a "near-zero" approach

[2020 Catheter Ablation Registry of the Italian Association of Arrhythmology and Cardiac Pacing]

Background: This report describes the findings of the 2020 Italian Catheter Ablation Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC). Methods: Data collection was retrospective. A standardized questionnaire was completed by each of the participating centers. Results: A total of 10 378 ablation procedures were performed by 66 institutions. Most centers (70%) have an electrophysiology laboratory, and 23% a hybrid cardiac surgery laboratory. All centers have a 3D mapping system. The median number of electrophysiologists and nurses involved in the electrophysiology laboratory was 3.5 and 3, respectively. An electrophysiology technician was involved in 35% of all centers. In 88.2% of cases, catheter ablation was performed for supraventricular arrhythmias; the most frequently treated arrhythmia was atrial fibrillation (39.4%), followed by atrioventricular nodal reentrant tachycardia (18.6%), and common atrial flutter (10.6%). In 72.9% of patients, catheter ablation was performed using a 3D mapping system, with a "near-zero" fluoroscopic approach in 37.7% of all patients. Conclusions: The 2020 Italian Catheter Ablation Registry confirmed that the electrophysiology activity was markedly affected by the COVID-19 pandemic; atrial fibrillation is the most frequently treated arrhythmia with an increasing number of procedures performed with a 3D mapping system and a "near-zero" approach