Signal Transceiver Transit Times and Propagation Delay Corrections for Ranging and Georeferencing Applications

The accuracy of ranging measurements depends critically on the knowledge of time delays undergone by signals when retransmitted by a remote transponder and due to propagation effects. A new method determines these delays for every single pulsed signal transmission. It utilizes four ground-based reference stations, synchronized in time and installed at well-known geodesic coordinates and a repeater in space, carried by a satellite, balloon, aircraft, and so forth. Signal transmitted by one of the reference bases is retransmitted by the transponder, received back by the four bases, producing four ranging measurements which are processed to determine uniquely the time delays undergone in every retransmission process. A minimization function is derived comparing repeater's positions referred to at least two groups of three reference bases, providing the signal transit time at the repeater and propagation delays, providing the correct repeater position. The method is applicable to the transponder platform positioning and navigation, time synchronization of remote clocks, and location of targets. The algorithm has been demonstrated by simulations adopting a practical example with the transponder carried by an aircraft moving over bases on the ground.CNPq Agency (Brazil)Brazil agency CNPqBrazil agency CAPESBrazil agency CAPE

Baseline characteristics of patients in the reduction of events with darbepoetin alfa in heart failure trial (RED-HF)

<p>Aims: This report describes the baseline characteristics of patients in the Reduction of Events with Darbepoetin alfa in Heart Failure trial (RED-HF) which is testing the hypothesis that anaemia correction with darbepoetin alfa will reduce the composite endpoint of death from any cause or hospital admission for worsening heart failure, and improve other outcomes.</p> <p>Methods and results: Key demographic, clinical, and laboratory findings, along with baseline treatment, are reported and compared with those of patients in other recent clinical trials in heart failure. Compared with other recent trials, RED-HF enrolled more elderly [mean age 70 (SD 11.4) years], female (41%), and black (9%) patients. RED-HF patients more often had diabetes (46%) and renal impairment (72% had an estimated glomerular filtration rate <60 mL/min/1.73 m2). Patients in RED-HF had heart failure of longer duration [5.3 (5.4) years], worse NYHA class (35% II, 63% III, and 2% IV), and more signs of congestion. Mean EF was 30% (6.8%). RED-HF patients were well treated at randomization, and pharmacological therapy at baseline was broadly similar to that of other recent trials, taking account of study-specific inclusion/exclusion criteria. Median (interquartile range) haemoglobin at baseline was 112 (106–117) g/L.</p> <p>Conclusion: The anaemic patients enrolled in RED-HF were older, moderately to markedly symptomatic, and had extensive co-morbidity.</p&gt

Caregiver burden before heart transplantation and long-term mechanical circulatory support: Findings from the Sustaining Quality of Life of the Aged: Transplant or Mechanical Support (SUSTAIN-IT) study

Background: Caregiving for heart failure (HF) patients is burdensome. We examined differences in caregiver burden for three groups of older advanced HF patients: (1) supported with mechanical circulatory support (MCS) before heart transplantation (HT MCS), (2) awaiting transplant without MCS (HT non-MCS), and (3) prior to long-term MCS and factors associated with burden. Methods: From 10/1/15-12/31/18, we enrolled 276 caregivers for HF patients from 13 U.S. sites: 85 HT MCS, 96 HT non-MCS, and 95 prior to long-term MCS. At enrollment, caregivers completed the Oberst Caregiving Burden Scale (15 items, 2 subscales: time (range=1-5; higher score=more time spent on task) and difficulty (range=1-5; higher score=higher difficulty of task) and other measures. Statistical analyses included descriptive statistics, ANOVA, chi-square tests, and linear regression. Results: Overall, caregivers were aged 60.8±9.8 years and predominantly white, female, spouses, well educated, and reported ≥1 comorbidities. Caregivers overall reported a moderate amount of time spent on tasks and slight task difficulty. Caregivers for HT non-MCS candidates reported significantly less perceived time spent on tasks than caregivers for HT MCS candidates and caregivers for patients prior to long-term MCS (2.2±0.74 vs 2.4±0.74 vs 2.5±0.71, respectively, p=0.02) and less perceived difficulty of tasks (1.2±0.33 vs 1.4±0.53 vs 1.4±0.54, respectively, p=0.01). Caregiver and patient factors were associated with caregiver burden. Conclusions: Prior to HT and long-term MCS, caregiver burden was low to moderate. Caregiver factors were predominantly associated with caregiver burden. Understanding caregiver burden and factors affecting caregiver burden may enhance preoperative advanced therapies discussions and guide caregiver support

Effectiveness of the Communication Tool in Improving Family Member Screening for Dilated Cardiomyopathy: Results of a Randomized Trial

BACKGROUND: Managing disease risk among first-degree relatives of probands diagnosed with a heritable disease is central to precision medicine. A critical component is often clinical screening, which is particularly important for conditions like dilated cardiomyopathy (DCM) that remain asymptomatic until severe disease develops. Nonetheless, probands are frequently ill-equipped to disseminate genetic risk information that motivates at-risk relatives to complete recommended clinical screening. An easily implemented remedy for this key issue has been elusive. METHODS: The DCM Precision Medicine Study developed , a booklet designed to help probands with DCM communicate genetic risk and the need for cardiovascular screening to their relatives. The effectiveness of the booklet in increasing cardiovascular clinical screening uptake among first-degree relatives was assessed in a multicenter, open-label, cluster-randomized, controlled trial. The primary outcome measured in eligible first-degree relatives was completion of screening initiated within 12 months after proband enrollment. Because probands randomized to the intervention received the booklet at the enrollment visit, eligible first-degree relatives were limited to those who were alive the day after proband enrollment and not enrolled on the same day as the proband. RESULTS: Between June 2016 and March 2020, 1241 probands were randomized (1:1) to receive (n=621) or not (n=620) within strata defined by site and self-identified race/ethnicity (non-Hispanic Black, non-Hispanic White, or Hispanic). Final analyses included 550 families (n=2230 eligible first-degree relatives) in the arm and 561 (n=2416) in the control arm. A higher percentage of eligible first-degree relatives completed screening in the arm (19.5% versus 16.0%), and the odds of screening completion among these first-degree relatives were higher in the arm after adjustment for proband randomization stratum, sex, and age quartile (odds ratio, 1.30 [1-sided 95% CI, 1.08-∞]). A prespecified subgroup analysis did not find evidence of heterogeneity in the adjusted intervention odds ratio across race/ethnicity strata (=0.90). CONCLUSIONS: , a booklet that can be provided to patients with DCM by clinicians with minimal additional time investment, was effective in increasing cardiovascular clinical screening among first-degree relatives of these patients. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03037632

Rare Variant Genetics and Dilated Cardiomyopathy Severity: The DCM Precision Medicine Study

BACKGROUND: Dilated cardiomyopathy (DCM) can lead to advanced disease, defined herein as necessitating a durable left ventricular assist device or a heart transplant (LVAD/HT). DCM is known to have a genetic basis, but the association of rare variant genetics with advanced DCM has not been studied. METHODS: We analyzed clinical and genetic sequence data from patients enrolled between 2016 and 2021 in the US multisite DCM Precision Medicine Study, which was a geographically diverse, multiracial, multiethnic cohort. Clinical evaluation included standardized patient interview and medical record query forms. DCM severity was classified into 3 groups: patients with advanced disease with LVAD/HT; patients with an implantable cardioverter defibrillator (ICD) only; or patients with no ICD or LVAD/HT. Rare variants in 36 DCM genes were classified as pathogenic or likely pathogenic or variants of uncertain significance. Confounding factors we considered included demographic characteristics, lifestyle factors, access to care, DCM duration, and comorbidities. Crude and adjusted associations between DCM severity and rare variant genetic findings were assessed using multinomial models with generalized logit link. RESULTS: Patients\u27 mean (SD) age was 51.9 (13.6) years; 42% were of African ancestry, 56% were of European ancestry, and 44% were female. Of 1198 patients, 347 had LVAD/HT, 511 had an ICD, and 340 had no LVAD/HT or ICD. The percentage of patients with pathogenic or likely pathogenic variants was 26.2%, 15.9%, and 15.0% for those with LVAD/HT, ICD only, or neither, respectively. After controlling for sociodemographic characteristics and comorbidities, patients with DCM with LVAD/HT were more likely than those without LVAD/HT or ICD to have DCM-related pathogenic or likely pathogenic rare variants (odds ratio, 2.3 [95% CI, 1.5-3.6]). The association did not differ by ancestry. Rare variant genetic findings were similar between patients with DCM with an ICD and those without LVAD/HT or ICD. CONCLUSIONS: Advanced DCM was associated with higher odds of rare variants in DCM genes adjudicated as pathogenic or likely pathogenic, compared with individuals with less severe DCM. This finding may help assess the risk of outcomes in management of patients with DCM and their at-risk family members. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03037632

Prevalence and Cumulative Risk of Familial Idiopathic Dilated Cardiomyopathy

IMPORTANCE: Idiopathic dilated cardiomyopathy (DCM) aggregates in families, and early detection in at-risk family members can provide opportunity to initiate treatment prior to late-phase disease. Most studies have included only White patients, yet Black patients with DCM have higher risk of heart failure-related hospitalization and death. OBJECTIVE: To estimate the prevalence of familial DCM among DCM probands and the age-specific cumulative risk of DCM in first-degree relatives across race and ethnicity groups. DESIGN, SETTING, AND PARTICIPANTS: A family-based, cross-sectional study conducted by a multisite consortium of 25 US heart failure programs. Participants included patients with DCM (probands), defined as left ventricular systolic dysfunction and left ventricular enlargement after excluding usual clinical causes, and their first-degree relatives. Enrollment commenced June 7, 2016; proband and family member enrollment concluded March 15, 2020, and April 1, 2021, respectively. EXPOSURES: The presence of DCM in a proband. MAIN OUTCOMES AND MEASURES: Familial DCM defined by DCM in at least 1 first-degree relative; expanded familial DCM defined by the presence of DCM or either left ventricular enlargement or left ventricular systolic dysfunction without known cause in at least 1 first-degree relative. RESULTS: The study enrolled 1220 probands (median age, 52.8 years [IQR, 42.4-61.8]; 43.8% female; 43.1% Black and 8.3% Hispanic) and screened 1693 first-degree relatives for DCM. A median of 28% (IQR, 0%-60%) of living first-degree relatives were screened per family. The crude prevalence of familial DCM among probands was 11.6% overall. The model-based estimate of the prevalence of familial DCM among probands at a typical US advanced heart failure program if all living first-degree relatives were screened was 29.7% (95% CI, 23.5% to 36.0%) overall. The estimated prevalence of familial DCM was higher in Black probands than in White probands (difference, 11.3% [95% CI, 1.9% to 20.8%]) but did not differ significantly between Hispanic probands and non-Hispanic probands (difference, -1.4% [95% CI, -15.9% to 13.1%]). The estimated prevalence of expanded familial DCM was 56.9% (95% CI, 50.8% to 63.0%) overall. Based on age-specific disease status at enrollment, estimated cumulative risks in first-degree relatives at a typical US advanced heart failure program reached 19% (95% CI, 13% to 24%) by age 80 years for DCM and 33% (95% CI, 27% to 40%) for expanded DCM inclusive of partial phenotypes. The DCM hazard was higher in first-degree relatives of non-Hispanic Black probands than non-Hispanic White probands (hazard ratio, 1.89 [95% CI, 1.26 to 2.83]). CONCLUSIONS AND RELEVANCE: In a US cross-sectional study, there was substantial estimated prevalence of familial DCM among probands and modeled cumulative risk of DCM among their first-degree relatives. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03037632

Screening for Dilated Cardiomyopathy in At-Risk First-Degree Relatives

BACKGROUND: Cardiovascular screening is recommended for first-degree relatives (FDRs) of patients with dilated cardiomyopathy (DCM), but the yield of FDR screening is uncertain for DCM patients without known familial DCM, for non-White FDRs, or for DCM partial phenotypes of left ventricular enlargement (LVE) or left ventricular systolic dysfunction (LVSD). OBJECTIVES: This study examined the yield of clinical screening among reportedly unaffected FDRs of DCM patients. METHODS: Adult FDRs of DCM patients at 25 sites completed screening echocardiograms and ECGs. Mixed models accounting for site heterogeneity and intrafamilial correlation were used to compare screen-based percentages of DCM, LVSD, or LVE by FDR demographics, cardiovascular risk factors, and proband genetics results. RESULTS: A total of 1,365 FDRs were included, with a mean age of 44.8 ± 16.9 years, 27.5% non-Hispanic Black, 9.8% Hispanic, and 61.7% women. Among screened FDRs, 14.1% had new diagnoses of DCM (2.1%), LVSD (3.6%), or LVE (8.4%). The percentage of FDRs with new diagnoses was higher for those aged 45 to 64 years than 18 to 44 years. The age-adjusted percentage of any finding was higher among FDRs with hypertension and obesity but did not differ statistically by race and ethnicity (16.2% for Hispanic, 15.2% for non-Hispanic Black, and 13.1% for non-Hispanic White) or sex (14.6% for women and 12.8% for men). FDRs whose probands carried clinically reportable variants were more likely to be identified with DCM. CONCLUSIONS: Cardiovascular screening identified new DCM-related findings among 1 in 7 reportedly unaffected FDRs regardless of race and ethnicity, underscoring the value of clinical screening in all FDRs

Genetic Architecture of Dilated Cardiomyopathy in Individuals of African and European Ancestry

IMPORTANCE: Black patients with dilated cardiomyopathy (DCM) have increased familial risk and worse outcomes than White patients, but most DCM genetic data are from White patients. OBJECTIVE: To compare the rare variant genetic architecture of DCM by genomic ancestry within a diverse population of patients with DCM. DESIGN: Cross-sectional study enrolling patients with DCM who self-identified as non-Hispanic Black, Hispanic, or non-Hispanic White from June 7, 2016, to March 15, 2020, at 25 US advanced heart failure programs. Variants in 36 DCM genes were adjudicated as pathogenic, likely pathogenic, or of uncertain significance. EXPOSURE: Presence of DCM. MAIN OUTCOMES AND MEASURES: Variants in DCM genes classified as pathogenic/likely pathogenic/uncertain significance and clinically actionable (pathogenic/likely pathogenic). RESULTS: A total of 505, 667, and 26 patients with DCM of predominantly African, European, or Native American genomic ancestry, respectively, were included. Compared with patients of European ancestry, a lower percentage of patients of African ancestry had clinically actionable variants (8.2% [95% CI, 5.2%-11.1%] vs 25.5% [95% CI, 21.3%-29.6%]), reflecting the lower odds of a clinically actionable variant for those with any pathogenic variant/likely pathogenic variant/variant of uncertain significance (odds ratio, 0.25 [95% CI, 0.17-0.37]). On average, patients of African ancestry had fewer clinically actionable variants in TTN (difference, -0.09 [95% CI, -0.14 to -0.05]) and other genes with predicted loss of function as a disease-causing mechanism (difference, -0.06 [95% CI, -0.11 to -0.02]). However, the number of pathogenic variants/likely pathogenic variants/variants of uncertain significance was more comparable between ancestry groups (difference, -0.07 [95% CI, -0.22 to 0.09]) due to a larger number of non-TTN non-predicted loss of function variants of uncertain significance, mostly missense, in patients of African ancestry (difference, 0.15 [95% CI, 0.00-0.30]). Published clinical case-based evidence supporting pathogenicity was less available for variants found only in patients of African ancestry (P \u3c .001). CONCLUSION AND RELEVANCE: Patients of African ancestry with DCM were less likely to have clinically actionable variants in DCM genes than those of European ancestry due to differences in genetic architecture and a lack of representation of African ancestry in clinical data sets