Prospective blinded evaluation of a novel sensing methodology designed to reduce inappropriate shocks by the subcutaneous implantable cardioverter-defibrillator

Background: Most inappropriate shocks from the subcutaneous implantable cardioverter-defibrillator (S-ICD) are caused by cardiac oversensing. A novel sensing methodology, SMART Pass (SP; Boston Scientific Corporation, Natick, MA), aims to reduce cardiac oversensing. Objective: The purpose of this study was to evaluate the effect of SP on shocks in ambulatory patients with S-ICD. Methods: Patients implanted in 2015–2016 and enrolled in a remote patient monitoring system were included and followed for 1 year. Shocks were adjudicated by 3 independent blinded reviewers as appropriate or inappropriate. Shock incidence was calculated for patients with SP programmed enabled or disabled at implantation, censoring patients when SP programming changed or at the last transmission. The SP setting (enabled vs disabled) was modeled as a time-dependent Cox regression variable. Results: The cohort consisted of 1984 patients, and a total of 880 shocks were adjudicated. At implantation, SP was enabled in 655 patients (33%) and disabled in 1329 patients (67%). SP reduced the risk for the first inappropriate shock by 50% (P <.001) and the risk for all inappropriate shocks by 68% (P <.001) in multivariate analysis adjusted for age and device programming. The incidence of inappropriate shocks was 4.3% in the SP enabled arm vs 9.7% in the SP disabled arm. The incidence of appropriate shocks was similar (5.2

Excitation Spectra and Thermodynamic Response of Segmented Heisenberg Spin Chains

The spectral and thermodynamic response of segmented quantum spin chains is analyzed using a combination of numerical techniques and finite-size scaling arguments. Various distributions of segment lengths are considered, including the two extreme cases of quenched and annealed averages. As the impurity concentration is increased, it is found that (i) the integrated spectral weight is rapidly reduced, (ii) a pseudo-gap feature opens up at small frequencies, and (iii) at larger frequencies a discrete peak structure emerges, dominated by the contributions of the smallest cluster segments. The corresponding low-temperature thermodynamic response has a divergent contribution due to the odd-site clusters and a sub-dominant exponentially activated component due to the even-site segments whose finite-size gap is responsible for the spectral weight suppression at small frequencies. Based on simple scaling arguments, approximate low-temperature expressions are derived for the uniform susceptibility and the heat capacity. These are shown to be in good agreement with numerical solutions of the Bethe ansatz equations for ensembles of open-end chains.Comment: RevTex, 9 pages with 6 figure

From "being at war" to "getting back on your feet": a qualitative study on experiences of patients with systemic sclerosis treated with hematopoietic stem cell transplantation

Objectives:To gain insight into the experiences of patients with diffuse cutaneous systemic sclerosis during and after autologous hematopoietic stem cell transplantation.Methods:Semi-structured interviews were conducted with patients who underwent hematopoietic stem cell transplantation in four university hospitals in the Netherlands. Interviews were transcribed verbatim and thematically analyzed.Results:Nine male and seven female patients were interviewed, median age 47 years (range: 27-68). Patients mentioned their life was severely disrupted before hematopoietic stem cell transplantation and remained unsettled a long time after treatment. Uncertainty because of disease progression, loss of control over health and the sense of time and fear of treatment-related adverse events were common during hospitalization. After hematopoietic stem cell transplantation, patients experienced more physical limitations than they had expected, and recovery took longer and was mentally taxing. Going back to work and finding a new balance in personal relations and social life was complicated. Patients described various strategies to deal with challenges. Family and friends provided essential support, although many experienced a dwindling social circle. Most patients also appreciated peer support. All patients were satisfied with the low threshold for contact with physicians and nurses during hospitalization. However, aftercare focused on medical aspects rather than on psychological well-being and social issues. Moreover, patients would have preferred to be better prepared on what to expect after discharge, and lacked information about self-management, prognosis, optimal recovery, work, sexuality, and family planning.Conclusion:Hematopoietic stem cell transplantation has a major physical and psychological impact on patients with diffuse cutaneous systemic sclerosis. The course of recovery after this intensive therapy was unexpectedly long for some patients and offer of support was far less pro-active post-HSCT compared to pre-HSCT and during HSCT.Analysis and support of clinical decision makin

Treatment decision-making in diffuse cutaneous systemic sclerosis: a patient's perspective

Objectives. To examine the treatment decision-making process of patients with dcSSc in the context of haematopoietic stem cell transplantation (HSCT).Methods. A qualitative semi-structured interview study was done in patients before or after HSCT, or patients who chose another treatment than HSCT. Thematic analysis was used. Shared decision-making (SDM) was assessed with the 9-item Shared Decision Making Questionnaire (SDM-Q-9).Results. Twenty-five patients [16 male/nine female, median age 47 (range 27-68) years] were interviewed: five pre-HSCT, 16 post-HSCT and four following other treatment. Whereas the SDM-Q-9 showed the decision-making process was perceived as shared [median score 81/100 (range 49-100)], we learned from the interviews that the decision was predominantly made by the rheumatologist, and patients were often steered towards a treatment option. Strong guidance of the rheumatologist was appreciated because of a lack of accessible, reliable and SSc-specific information, due to the approach of the decision-making process of the rheumatologist, the large consequence of the decision and the trust in their doctor. Expectations of outcomes and risks also differed between patients. Furthermore, more than half of patients felt they had no choice but to go for HSCT, due to rapid deterioration of health and the perception of HSCT as 'the holy grail'.Conclusion. This is the first study that provides insight into the decision-making process in dcSSc. This process is negatively impacted by a lack of disease-specific education about treatment options. Additionally, we recommend exploring patients' preferences and understanding of the illness to optimally guide decision-making and to provide tailor-made information.Analysis and support of clinical decision makin

Torque teno virus loads after kidney transplantation predict allograft rejection but not viral infection

The main challenge of immunosuppressive therapy after solid organ transplantation is to create a new immunological balance that prevents organ rejection and does not promote opportunistic infection. Torque teno virus (TTV), a ubiquitous and non-pathogenic single-stranded DNA virus, has been proposed as a marker of functional immunity in immunocompromised patients. Here we investigate whether TTV loads predict the risk of common viral infection and allograft rejection in kidney transplantation recipients.In a retrospective cohort of 389 kidney transplantation recipients, individual TTV loads in were measured by qPCR in consecutive plasma samples during one year follow-up. The endpoints were allograft rejection, BK polyomavirus (BKPyV) viremia and cytomegalovirus (CMV) viremia. Repeated TTV measurements and rejection and infection survival data were analysed in a joint model.During follow-up, TTV DNA detection in the transplant recipients increased from 85 to 100%. The median viral load increased to 107 genome copies/ml within three months after transplantation. Rejection, BKPyV viremia and CMV viremia occurred in 23%, 27% and 17% of the patients, respectively. With every 10-fold TTV load-increase, the risk of rejection decreased considerably (HR: 0.74, CI 95%: 0.71-0.76), while the risk of BKPyV and CMV viremia remained the same (HR: 1.03, CI 95%: 1.03-1.04 and HR: 1.01, CI 95%: 1.01-1.01).In conclusion, TTV load kinetics predict allograft rejection in kidney transplantation recipients, but not the BKPyV and CMV infection. The potential use of TTV load levels as a guide for optimal immunosuppressive drug dosage to prevent allograft rejection deserves further validation.Development and application of statistical models for medical scientific researc

Update of the Preventive Antibiotics in Stroke Study (PASS): Statistical analysis plan

Background: Infections occur in 30% of stroke patients and are associated with unfavorable outcomes. Preventive antibiotic therapy lowers the infection rate after stroke, but the effect of preventive antibiotic treatment on functional outcome in patients with stroke is unknown. The PASS is a multicenter, prospective, phase three, randomized, open-label, blinded end-point (PROBE) trial of preventive antibiotic therapy in acute stroke. Patients are randomly assigned to either ceftriaxone at a dose of 2 g, given every 24 h intravenously for 4 days, in addition to standard stroke-unit care, or standard stroke-unit care without preventive antibiotic therapy. The aim of this study is to assess whether preventive antibiotic treatment improves functional outcome at 3 months by preventing infections. This paper presents in detail the statistical analysis plan (SAP) of the Preventive Antibiotics in Stroke Study (PASS) and was submitted while the investigators were st

The learning curve associated with the introduction of the subcutaneous implantable defibrillator

Aims: The subcutaneous implantable cardioverter defibrillator (S-ICD) was introduced to overcome complications related to transvenous leads. Adoption of the S-ICD requires implanters to learn a new implantation technique. The aim of this study was to assess the learning curve for S-ICD implanters with respect to implant-related complications, procedure time, and inappropriate shocks (IASs). Methods and results: In a pooled cohort from two clinical S-ICD databases, the IDE Trial and the EFFORTLESS Registry, complications, IASs at 180 days follow-up and implant procedure duration were assessed. Patients were grouped in quartiles based on experience of the implanter and Kaplan-Meier estimates of complication and IAS rates were calculated. A total of 882 patients implanted in 61 centres by 107 implanters with a median of 4 implants (IQR 1,8) were analysed. There were a total of 59 patients with complications and 48 patients with IAS. The complication rate decreased significantly from 9.8% in Quartile 1 (least experience) to 5.4% in Quartile 4 (most experience) (P = 0.02) and non-significantly for IAS from 7.9 to 4.8% (P = 0.10). Multivariable analysis demonstrated a hazard ratio of 0.78 (P = 0.045) for complications and 1.01 (P = 0.958) for IAS. Dual-zone programming increased with experience of the individual implanter (P 13 implants). Conclusion: There is a short and significant learning curve associated with physicians adopting the S-ICD. Performance stab