bluuebunny/crossref_metadata_2025_split huggingface dataset:
Are Changes in Heart Rate Variability in Middle‐Aged and Older People Normative or Caused by Pathological Conditions? Findings From a Large Population‐Based Longitudinal Cohort Study
Authors: Jandackova Vera K. , Scholes Shaun , Britton Annie , Steptoe Andrew 
Published: September 2018

Background

No study to date has investigated longitudinal trajectories of cardiac autonomic modulation changes with aging; therefore, we lack evidence showing whether these changes occur naturally or are secondary to disease or medication use. This study tested whether heart rate variability (
HRV
) trajectories from middle to older age are largely normative or caused by pathological changes with aging in a large prospective cohort. We further assessed whether
HRV
changes were modified by socioeconomic status, ethnicity, or habitual physical activity.

Methods and Results

This study involved 3176 men and 1238 women initially aged 44 to 69 years (1997–1999) from the
UK
Whitehall
II
population‐based cohort. We evaluated time‐ and frequency‐domain
HRV
measures of short‐term recordings at 3 time points over a 10‐year period. Random mixed models with time‐varying covariates were applied. Cross‐sectionally,
HRV
measures were lower for men than for women, for participants with cardiometabolic conditions, and for participants reporting use of medications other than beta blockers. Longitudinally,
HRV
measures decreased significantly with aging in both sexes, with faster decline in younger age groups.
HRV
trajectories were not explained by increased prevalence of cardiometabolic problems and/or medication use. In women, cardiometabolic problems were associated with faster decline in the standard deviation of all intervals between R waves with normal‐to‐normal conduction, in low‐frequency
HRV
, and in low‐frequency
HRV
in normalized units. Socioeconomic status, ethnicity, and habitual physical activity did not have significant effects on
HRV
trajectories.

Conclusions
Our investigation showed a general pattern and timing of changes in indices of cardiac autonomic modulation from middle to older age. These changes seem likely to reflect the normal aging process rather than being secondary to cardiometabolic problems and medication use.
Vascular Smooth Muscle Sirtuin‐1 Protects Against Aortic Dissection During Angiotensin II–Induced Hypertension
Authors: Fry Jessica L. , Shiraishi Yasunaga , Turcotte Raphaël , Yu Xunjie , Gao Yuan Z. , Akiki Rachid , Bachschmid Markus , Zhang Yanhang , Morgan Kathleen G. , Cohen Richard A. , Seta Francesca 
Published: September 2018

Background

Sirtuin‐1 (SirT1), a nicotinamide adenine dinucleotide
+
–dependent deacetylase, is a key enzyme in the cellular response to metabolic, inflammatory, and oxidative stresses; however, the role of endogenous SirT1 in the vasculature has not been fully elucidated. Our goal was to evaluate the role of vascular smooth muscle SirT1 in the physiological response of the aortic wall to angiotensin
II
, a potent hypertrophic, oxidant, and inflammatory stimulus.

Methods and Results

Mice lacking SirT1 in vascular smooth muscle (ie, smooth muscle SirT1 knockout) had drastically high mortality (70%) caused by aortic dissection after angiotensin
II
infusion (1 mg/kg per day) but not after an equipotent dose of norepinephrine, despite comparable blood pressure increases. Smooth muscle SirT1 knockout mice did not show any abnormal aortic morphology or blood pressure compared with wild‐type littermates. Nonetheless, in response to angiotensin
II
, aortas from smooth muscle SirT1 knockout mice had severely disorganized elastic lamellae with frequent elastin breaks, increased oxidant production, and aortic stiffness compared with angiotensin
II
–treated wild‐type mice. Matrix metalloproteinase expression and activity were increased in the aortas of angiotensin
II
–treated smooth muscle SirT1 knockout mice and were prevented in mice overexpressing SirT1 in vascular smooth muscle or with use of the oxidant scavenger tempol.

Conclusions
Endogenous SirT1 in aortic smooth muscle is required to maintain the structural integrity of the aortic wall in response to oxidant and inflammatory stimuli, at least in part, by suppressing oxidant‐induced matrix metalloproteinase activity. SirT1 activators could potentially be a novel therapeutic approach to prevent aortic dissection and rupture in patients at risk, such as those with hypertension or genetic disorders, such as Marfan's syndrome.
Rates of Atrial Fibrillation in Black Versus White Patients With Pacemakers
Authors: Kamel Hooman , Kleindorfer Dawn O. , Bhave Prashant D. , Cushman Mary , Levitan Emily B. , Howard George , Soliman Elsayed Z. 
Published: September 2018

Background

Black
US
residents experience higher rates of ischemic stroke than white residents but have lower rates of clinically apparent atrial fibrillation (
AF
), a strong risk factor for stroke. It is unclear whether black persons truly have less
AF
or simply more undiagnosed
AF
.

Methods and Results

We obtained administrative claims data from state health agencies regarding all emergency department visits and hospitalizations in California, Florida, and New York. We identified a cohort of patients with pacemakers, the regular interrogation of which reduces the likelihood of undiagnosed
AF
. We compared rates of documented
AF
or atrial flutter at follow‐up visits using Kaplan–Meier survival statistics and Cox proportional hazards models adjusted for demographic characteristics and vascular risk factors. We identified 10 393 black and 91 380 white patients without documented
AF
or atrial flutter before or at the index visit for pacemaker implantation. During 3.7 (±1.8) years of follow‐up, black patients had a significantly lower rate of
AF
(21.4%; 95%
CI
19.8–23.2) than white patients (25.5%; 95%
CI
24.9–26.0). After adjustment for demographic characteristics and comorbidities, black patients had a lower hazard of
AF
(hazard ratio 0.91; 95%
CI
0.86–0.96), a higher hazard of atrial flutter (hazard ratio 1.29; 95%
CI
1.11–1.49), and a lower hazard of the composite of
AF
or atrial flutter (hazard ratio 0.94; 95%
CI
0.88–99).

Conclusions

In a population‐based sample of patients with pacemakers, black patients had a lower rate of
AF
compared with white patients. These findings indicate that the persistent racial disparities in rates of ischemic stroke are likely to be related to factors other than undiagnosed
AF
.
Incidence and Costs Related to Lead Damage Occurring Within the First Year After a Cardiac Implantable Electronic Device Replacement Procedure
Authors: Nichols Christine I. , Vose Joshua G. , Mittal Suneet 
Published: September 2018

Background
Inadvertent damage to leads for transvenous pacemakers, implantable cardioverter‐defibrillators, and cardiac resynchronization therapy defibrillators is an important complication associated with generator‐replacement procedures. We sought to estimate the incidence and costs associated with transvenous lead damage following cardiac implantable electronic device replacement.

Methods and Results

Using the Truven Health Analytics MarketScan Commercial Research Database, we identified health care claims between 2009 and 2013 for lead damage following generator replacement. Patients were identified by claims with a procedure code for cardiac implantable electronic device replacement and then evaluated for 1 year. All follow‐up visits for lead damage were identified, and incidence, risk factors, and hospitalization costs were determined. A total of 22 557 patients with pacemakers, 20 632 with implantable cardioverter‐defibrillators, and 2063 with cardiac resynchronization therapy defibrillators met selection criteria. Incidence of lead damage was 0.46% for pacemaker replacement, 1.27% for implantable cardioverter‐defibrillator replacement, and 1.94% for cardiac resynchronization therapy defibrillator replacement procedures (
P
<0.001). After adjusting for patient characteristics, patients with implantable cardioverter‐defibrillators and cardiac resynchronization therapy defibrillators demonstrated risk of lead damage that was, respectively, double (hazard ratio 2.00, 95%
CI
1.57–2.55) and >2.5 times (hazard ratio 2.58, 95%
CI
1.73–3.83) that of patients with pacemakers. Lead revision or repair procedures were associated with increased inpatient hospitalization costs (mean $19 959 for pacemaker, $24 885 for implantable cardioverter‐defibrillator, and $46 229 for cardiac resynchronization therapy defibrillator;
P
=0.048, Kruskal–Wallis test).

Conclusions
These findings establish the first objective assessment of the incidence, risk factors, and economic burden of lead damage following cardiac implantable electronic device replacement in the United States. New care algorithms are warranted to avoid these events, which impose substantial burdens on patients, physicians, and payors.
Coronary CT Angiography Versus Standard Emergency Department Evaluation for Acute Chest Pain and Diabetic Patients: Is There Benefit With Early Coronary CT Angiography?
Authors: Truong Quynh A. , Schulman‐Marcus Joshua , Zakroysky Pearl , Chou Eric T. , Nagurney John T. , Fleg Jerome L. , Schoenfeld David A. , Udelson James E. , Hoffmann Udo , Woodard Pamela K. 
Published: September 2018

Background

Cardiac computed tomography angiography (
CCTA
) reduces emergency department length of stay compared with standard evaluation in patients with low‐ and intermediate‐risk acute chest pain. Whether diabetic patients have similar benefits is unknown.

Methods and Results

In this prespecified analysis of the Rule Out Myocardial Ischemia/Infarction by Computer Assisted Tomography (
ROMICAT II)
multicenter trial, we randomized 1000 patients (17% diabetic) with symptoms suggestive of acute coronary syndrome to
CCTA
or standard evaluation. The rate of acute coronary syndrome was 8% in both diabetic and nondiabetic patients (
P
=1.0). Length of stay was unaffected by the
CCTA
strategy for diabetic patients (23.9 versus 27.2 hours,
P
=0.86) but was reduced for nondiabetic patients compared with standard evaluation (8.4 versus 26.5 hours,
P
<0.0001;
P
interaction=0.004).
CCTA
resulted in 3‐fold more direct emergency department discharge in both groups (each
P
≤0.0001,
P
interaction=0.27). No difference in hospital admissions was seen between the 2 strategies in diabetic and nondiabetic patients (
P
interaction=0.09). Both groups had more downstream testing and higher radiation doses with
CCTA
, but these were highest in diabetic patients (all
P
interaction≤0.04). Diabetic patients had fewer normal
CCTAs
than nondiabetic patients (32% versus 50%,
P
=0.003) and similar normalcy rates with standard evaluation (
P
=0.70). Notably, 66% of diabetic patients had no or mild stenosis by
CCTA
with short length of stay comparable to that of nondiabetic patients (
P
=0.34), whereas those with >50% stenosis had a high prevalence of acute coronary syndrome, invasive coronary angiography, and revascularization.

Conclusions

Knowledge of coronary anatomy with
CCTA
is beneficial for diabetic patients and can discriminate between lower risk patients with no or little coronary artery disease who can be discharged immediately and higher risk patients with moderate to severe disease who warrant further workup.

Clinical Trial Registration

URL
:
https://www.clinicaltrials.gov/
. Unique identifier:
NCT
01084239.
Physical Activity, Sedentary Time, and Cardiovascular Disease Biomarkers at Age 60 to 64 Years
Authors: Elhakeem Ahmed , Cooper Rachel , Whincup Peter , Brage Soren , Kuh Diana , Hardy Rebecca 
Published: September 2018

Background

We examined associations of objectively measured physical activity (
PA
) and sedentary time with cardiovascular disease biomarkers at age 60 to 64 years. This included investigation of sex differences and the extent to which associations may be mediated by adiposity.

Methods and Results

Participants were 795 men and 827 women aged 60 to 64 years from the Medical Research Council National Survey of Health and Development. Combined heart rate and movement sensors worn for 5 consecutive days were used to derive overall
PA
energy expenditure,
kJ
/kg per day) and time spent sedentary (<1.5 metabolic equivalent of tasks), in light PA (1.5–3 metabolic equivalent of tasks) and moderate‐to‐vigorous intensity
PA
(>3 metabolic equivalent of tasks). Linear regression models were used to relate each
PA
parameter to inflammatory (C‐reactive protein, interleukin‐6), endothelial (tissue‐plasminogen activator, E‐selectin) and adipokine (leptin, adiponectin) markers extracted from fasting blood samples. Greater time in light
PA
and moderate‐to‐vigorous intensity
PA
and less sedentary time were associated with more favorable biomarker levels. For C‐reactive protein, interleukin‐6, and leptin, these differences were greater among women than men. For example, % differences (95% confidence intervals) in leptin for men and women per SD increases in sedentary time: 7.9 (2.7, 13.0) and 20.6 (15.3, 25.8); light intensity
PA
: −3.8 (−8.9, 12.7) and −17.7 (−23.1, −12.4), moderate‐to‐vigorous intensity
PA
: −12.9 (−17.9, −8.0) and −18.3 (−23.4, −13.1). Fat mass mediated a greater proportion of these associations in women than men.

Conclusions

Greater light
PA
and moderate‐to‐vigorous intensity
PA
and less sedentary time in early old age were associated with more favorable cardiovascular biomarker profiles. Fat mass partially mediated these associations but more strongly in women than men, which explained sex differences.
Negative Carotid Artery Remodeling in Early Type 2 Diabetes Mellitus and Increased Carotid Plaque Vulnerability in Obesity as Assessed by Magnetic Resonance Imaging
Authors: Laugesen Esben , Høyem Pernille , Thrysoe Samuel , Hansen Esben Søvsø Szocska , Mikkelsen Anders F. Stegmann , Kerwin William S. , Poulsen Per L. , Hansen Troels K. , Kim W. Yong 
Published: September 2018

Background

Ischemic stroke from carotid plaque embolism remains a major cause of morbidity in patients with type 2 diabetes mellitus (T2
DM
). However, the effect of early T2
DM
and obesity on carotid remodeling and plaque burden remains elusive. We assessed carotid remodeling and plaque composition by carotid magnetic resonance imaging in patients with short‐duration T2
DM
compared with a sex‐ and age‐matched control group.

Methods and Results

One hundred patients with T2
DM
(duration <5 years) and 100 sex‐ and age‐matched controls underwent bilateral carotid artery magnetic resonance imaging in a 1.5‐T magnetic resonance imaging scanner. Plaque burden was quantified by normalized wall index, maximum wall thickness, maximum wall area, and minimum lumen size. Plaque morphology was quantified by calcified plaque volume, necrotic core volume, and loose matrix volume. Magnetic resonance imaging data were available for 149 and 177 carotid arteries from T2
DM
patients and controls, respectively. Adjusted for age and sex, T2
DM
was associated with increased plaque burden indicated by a higher normalized wall index (ratio 1.03 [95% confidence interval, 1.002; 1.06],
P
=0.03), and negative remodeling indicated by a lower minimum lumen area (ratio 0.81 [0.74; 0.89],
P
<0.001), and lower maximum wall area (ratio 0.94 [0.88; 1.00],
P
=0.048) compared with controls. In both T2
DM
and controls, body mass index ≥30.0 kg/m
2
was associated with an 80% increase in total calcified plaque volume, and a 44% increase in necrotic core volume compared with body mass index <25.0 kg/m
2
.

Conclusions

Short‐duration T2
DM
was associated with increased carotid plaque burden and negative remodeling. Obesity was associated with increased carotid artery necrotic core volume and calcification independently of diabetes mellitus status.

Clinical Trial Registration

URL
:
https://www.clinicaltrials.gov
. Unique identifier:
NCT
00674271.
Association of Gout With Long‐Term Cardiovascular Outcomes Among Patients With Obstructive Coronary Artery Disease
Authors: Pagidipati Neha J. , Clare Robert M. , Keenan Robert T. , Chiswell Karen , Roe Matthew T. , Hess Connie N. 
Published: September 2018

Background
Epidemiological studies demonstrating a relationship between gout and cardiovascular disease are older and predate modern cardiovascular preventive therapy. We assessed the contemporary association between gout and cardiovascular disease in patients with obstructive coronary artery disease.

Methods and Results

Data were from the Duke Databank for Cardiovascular Diseases, which followed up patients undergoing cardiac catheterization with obstructive coronary artery disease at Duke University Medical Center (1998–2013). We assessed the relationship between gout diagnosis at baseline or during follow‐up and the primary composite outcome of cardiovascular death, myocardial infarction, or stroke, adjusting for differences in baseline clinical factors. Secondary end points included cardiovascular death and all‐cause mortality. New, postbaseline, gout diagnosis was included as a time‐dependent covariate. Among 17 201 patients, 1406 (8.2%) had baseline gout and a high burden of cardiovascular risk factors, but high rates of optimal medical therapy. Over a median follow‐up of 6.4 years, gout diagnosis at time of catheterization was not associated with the primary outcome (hazard ratio [95% confidence interval], 1.05 [0.96–1.15];
P
=0.31) or cardiovascular death (hazard ratio [95% confidence interval], 1.10 [0.99–1.22];
P
=0.08), but was associated with increased all‐cause mortality (hazard ratio [95% confidence interval], 1.13 [1.05–1.23];
P
=0.002). After including new, postbaseline, gout diagnosis, the instantaneous risk of the primary outcome was significantly associated with prior gout diagnosis (hazard ratio [95% confidence interval], 1.15 [1.07–1.25];
P
=0.0004).

Conclusions
A clinical history of gout is associated with worse outcomes in a contemporary population of patients with obstructive coronary artery disease. This increased risk exists despite high levels of optimal baseline cardiovascular disease medical therapy, suggesting that residual cardiovascular risk is not addressed by standard medical therapy.
Increased Muscle Mass Protects Against Hypertension and Renal Injury in Obesity
Authors: Butcher Joshua T. , Mintz James D. , Larion Sebastian , Qiu Shuiqing , Ruan Ling , Fulton David J. , Stepp David W. 
Published: September 2018

Background
Obesity compromises cardiometabolic function and is associated with hypertension and chronic kidney disease. Exercise ameliorates these conditions, even without weight loss. Although the mechanisms of exercise's benefits remain unclear, augmented lean body mass is a suspected mechanism. Myostatin is a potent negative regulator of skeletal muscle mass that is upregulated in obesity and downregulated with exercise. The current study tested the hypothesis that deletion of myostatin would increase muscle mass and reduce blood pressure and kidney injury in obesity.

Methods and Results

Myostatin knockout mice were crossed to
db/db
mice, and metabolic and cardiovascular functions were examined. Deletion of myostatin increased skeletal muscle mass by ≈50% to 60% without concomitant weight loss or reduction in fat mass. Increased blood pressure in obesity was prevented by the deletion of myostatin, but did not confer additional benefit against salt loading. Kidney injury was evident because of increased albuminuria, which was abolished in obese mice lacking myostatin. Glycosuria, total urine volume, and whole kidney NOX‐4 levels were increased in obesity and prevented by myostatin deletion, arguing that increased muscle mass provides a multipronged defense against renal dysfunction in obese mice.

Conclusions
These experimental observations suggest that loss of muscle mass is a novel risk factor in obesity‐derived cardiovascular dysfunction. Interventions that increase muscle mass, either through exercise or pharmacologically, may help limit cardiovascular disease in obese individuals.
Repossessing Property in South Asia: Land, Rights, and Law across the Early Modern/Modern Divide-Introduction
Authors: Chaudhry Faisal 
Published: September 2018

AbstractThe introductory essay to this special double issue on “Repossessing Property in South Asia: Land, Rights and Law Across the Early Modern/Modern Divide” reviews existing historical scholarship on land control and proprietary right in the Indian subcontinent in order to contextualize the contribution made by the articles that follow. Dividing earlier writings—by historians and anthropologists since the 1950s—into three phases/thematics, the introduction shows how work on South Asia has long grappled with property both as a material relation and as an alien cultural category. Making the case that we must think about property’s conceptual history as being necessitated by more than just the critique of Eurocentrism, the essay clarifies how the articles that follow both continue and extend past discussion. Overall, it argues that by providing integrated perspectives on property’s materialandideational dimensions, our articles will be illuminating both to scholars of Afro-Asia and those interested in law, political economy and political culture more generally.
Why Was the Color Violet Rarely Used by Artists before the 1860s?
Authors: Tager Allen 
Published: September 2018

AbstractAlthough the color violet is now used in a wide variety of everyday products, ranging from toys to clothing to cars, and although it now appears commonly in artistic works, violet was rarely used in fine art before the early 1860s. The color violet only became an integral part of modern culture and life with the rise of the French Impressionists. I investigated the use of violet in over 130,000 artworks prior to 1863 and found that it appeared in about .06 percent of the paintings. Violet was used substantially more frequently in Impressionist works, and remains popular in fine art and in popular culture today. I examine several explanations for the explosion of the use of violet in the art world during the Impressionist era, and conclude that a cognitive-perceptual explanation, based on the heightened sensitivity of the Impressionists to short wavelengths, may account for it. The findings fit with a new understanding about evolutionary changes in planetary light and human adaptation to light.
The Optical Autocovariance Wind Lidar. Part II: Green OAWL (GrOAWL) Airborne Performance and Validation
Authors: Baidar S. , Tucker S. C. , Beaubien M. , Hardesty R. M. 
Published: September 2018

AbstractA two-look airborne Doppler wind lidar operating at the 532-nm laser wavelength, the Green Optical Autocovariance Wind Lidar (GrOAWL), was built and flown aboard the NASA WB-57 research aircraft. Flight campaign goals were to validate the instrument wind measurements and to demonstrate the two-look measurement concept proposed for spaceborne mission concepts such as the Atmospheric Transport, Hurricanes, and Extratropical Numerical Weather Prediction with the Optical Autocovariance Wind Lidar (ATHENA-OAWL) mission. The GrOAWL-measured winds were compared with collocated dropsonde measurements. Line-of-sight velocity (LOSV) measurements for the individual GrOAWL looks showed excellent agreement with dropsondes (R2 > 0.9). The LOSV biases were very small and not statistically different from 0 m s−1 at the 95% confidence interval (−0.07 ± 0.07 m s−1 and 0.01 ± 0.07 m s−1 for look 1 and look 2, respectively). The wind speed and direction profiles retrieved by combining the two GrOAWL looks were also in very good agreement (R2 > 0.85). An instrument performance model indicated the instrument wind measurement precision was likely lowered (uncertainty was increased) by a factor of ~3.3 during the flights relative to predicted “as built” instrument performance. The reduced performance was not observed during ground-based atmospheric testing and thus has been attributed to impacts of the harsh operating conditions of the WB-57 aircraft (high vibration, thermal gradients, and high humidity). The exercise of scaling the GrOAWL instrument performance and grid scale to space showed space-based OAWL wind measurements would yield products with precision at least as good as the GrOAWL instrument.