Background-The association between higher body mass index (BMI) and lower B-type natriuretic peptide (BNP) level is thought to be mediated by expression of the natriuretic peptide clearance receptor (NPR-C) in adipose tissue. To explore this association, we tested 2 hypotheses: (1) that N-terminal (NT)-proBNP, which is not believed to bind NPR-C, would not be associated with BMI and (2) that lower BNP would be more closely associated with fat mass than with lean mass. Methods and Results-Measurements of BNP, NT-proBNP, and body composition by direct dual energy x-ray absorptiometry (DEXA) were performed in 2707 subjects from the Dallas Heart Study. The associations between obesity and low BNP (Ͻ4 ng/L) or low NT-proBNP (lowest sex-specific quartile) were evaluated with multivariable logistic regression models stratified by sex and adjusted for age, race/ethnicity, hypertension, left ventricular mass, and end-diastolic volume. Higher BMI was independently associated with lower BNP and NT-proBNP (all PϽ0.001). When BMI was replaced with both DEXA-derived lean and fat mass, greater lean mass, but not fat mass, was associated with low BNP and NT-proBNP levels. Conclusions-In a large, population-based cohort, we confirm the previously described association between higher BMIand lower BNP and demonstrate a similar inverse association between BMI and NT-proBNP. Interestingly, both BNP and NT-proBNP are more closely associated with lean mass than with fat mass. These findings do not support the hypothesis that the lower BNP levels seen in obesity are driven by enhanced BNP clearance mediated via NPR-C.
Background-Although gender-specific criteria are common for defining cardiac traits such as left ventricular hypertrophy, left ventricular ejection fraction (LVEF) thresholds widely used in clinical practice have traditionally been the same for women and men, perhaps because it remains uncertain whether there is a systematic difference in LVEF between genders. Methods and Results-Using cardiac magnetic resonance imaging in a probability-based sample of Dallas County residents aged 30 to 65 years (1435 women and 1183 men), we compared LVEF in women and men. The association of gender with stroke volume independent of end-diastolic volume (EDV) or other potential confounders was assessed by multivariable analysis. Gender-specific thresholds for a low LVEF were defined at the 2.5th percentile in women and men from a healthy reference subpopulation. The median (25th, 75th percentile) LVEF was higher in women than in men (75% [70%, 79%] in women versus 70% [65%, 75%] in men, PϽ0.001). Left ventricular EDV and end-systolic volume indexed to body surface area were smaller in women than in men (PϽ0.001 for both). Gender remained significantly associated with stroke volume, independent of EDV and other potential confounders in multivariable analysis. A low LVEF was defined as below 61% in women and below 55% in men. Conclusions-Women have a higher LVEF than men in the general population, secondary to a higher stroke volume for a given EDV independent of known potential confounders.
Southwestern Medical Center at Dallas,and 6 Veterans Affairs North Texas Health Care System, Dallas, TX, USA Background Atazanavir (ATV), an HIV protease inhibitor (PI) that may be preferred for the treatment of HIV-infected patients with cardiovascular comorbidities because of its favourable effects on plasma lipids, has been associated with cardiac rhythm disturbances. ObjectiveTo quantify the effect of ATV on corrected QT (QTc) and QTc dispersion (QTd), markers of the potential for cardiac dysrhythmia, in patients switching from other PIs to ATV. MethodsIn this prospective, single-centre, open-label study, 12-lead electrocardiograms were performed for subjects at baseline, 2 h after the first dose of ATV, and 1 month after initiation of ATV. ResultsTwenty-one patients (19 received ritonavir-boosted ATV) completed the study. There was a trend towards an increase in the QTc at 2 h after the first dose [mean AE standard deviation 3.19 AE 8.0 ms; 95% confidence interval (CI) À 0.47 to 6.85 ms; P 5 0.084]. There was no difference between QTc values at baseline and at 1 month ( À 1.5 AE 8.75 ms; 95% CI À 5.50 to 2.46; P 5 0.43). There was a nonsignificant decrease in the QTd between baseline and 2 h ( À 5.1 AE 15.19 ms; 95% CI À 13.22 to 2.96; P 5 0.197) and between baseline and 1 month ( À 0.61 AE 15.04 ms; 95% CI À 8.1 to 6.87; P 5 0.865). A significant increase in the PR interval (7.4 AE 10.7 ms; 95% CI 2.5 to 12.25 ms; P 5 0.005) was observed at 1 month. ConclusionsThe use of ATV did not result in increases in the QTc interval or QTd. However, PR interval monitoring may be warranted in patients with underlying heart block or those treated with atrioventricular nodal blocking agents. IntroductionAtazanavir (ATV) is the newest protease inhibitor (PI) approved for use in highly active antiretroviral therapy (HAART). Recent studies suggest that this PI may not be associated with the dyslipidaemia commonly seen with other PIs, and thus ATV may be an alternative for HIVpositive patients experiencing this adverse drug effect [1,2]. However, ATV has been associated with atrioventricular (AV) block, bradycardia and prolongation of the corrected QT (QTc) interval in some patients [3,4]. Acquired long-QT syndrome, drug-induced QT prolongation, and torsades de pointes (TdP) have also been previously reported in HIV-infected patients [5][6][7][8][9][10][11][12][13] Methods PatientsThis was a prospective, single-centre, open-label study.Patients were enrolled in the study from November 2003 to December 2004. Patients were included in the study if they were being treated with HAART at the HIV Clinic at the Dallas Veterans Affairs (VA) Medical Center, were418 years of age, had a documented diagnosis of HIV, were able to give informed consent, were capable of attending ambulatory care services, and were deemed appropriate candidates for the addition of ATV to their HAART regimen. Patients were excluded if they were hospitalized, required to take oral antacids within 2 h of ATV administration, histamine receptor antagonists an...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.