2,852 research outputs found

    Feasibility of Focused Cardiac Ultrasound in Pre-participation Screening

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    Objective: Current American Heart Association (AHA) guidelines for pre-participation athletic screening recommend a 12-point history and exam to minimize the risk of sudden cardiac death. We tested the hypothesis that focused cardiac ultrasound (FCU) performed and simultaneously interpreted by a cardiologist using a handheld ultrasound device would be a feasible addition. Methods: We performed pre-participation screening according to AHA recommendations on high school athletes in a multi-purpose room at their school. In addition to the standard 12-point assessment, a cardiologist simultaneously performed and interpreted a FCU on each athlete using a handheld ultrasound. Results: The mean age of the athletes was 16.6 ± 3.4 years; 68% were male. No evidence of left ventricular hypertrophy, cardiomyopathy, bicuspid aortic valve, or aortopathy was identified. Coronary ostia could not be visualized. Echocardiography added 1.35 ± 0.51 minutes to the standard exam. Conclusion: This feasibility study suggests that the addition of handheld echocardiography with real-time interpretation performed by a cardiologist to a standard AHA pre-participation screening adds less than two minutes of time to the assessment. While the study is not as comprehensive as an office based echocardiogram, it can provide valuable information which may be useful in ruling out some of the most common causes of sudden cardiac death in the young athlete or in selecting those who would benefit from further testing

    On the energy-delay tradeoff and relay positioning of wireless butterfly networks

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    This paper considers energy-delay tradeoff (EDT) of data transmission in wireless network coded butterfly networks (WNCBNs) where two sources convey their data to two destinations with the assistance of a relay employing either physical-layer network coding (PNC) or analog network coding (ANC). Hybrid automatic repeat request with incremental redundancy (HARQIR) is applied for a reliable communication. Particularly, we first investigate the EDT of both PNC and ANC schemes in WNCBNs to evaluate their energy efficiency. It is found that there is no advantage of using a relay in a high power regime. However, in a low power regime, the PNC scheme is shown to be more energy efficient than both the ANC and direct transmission (DT) schemes if the relay is located far from the sources, while both the PNC and ANC schemes are less energy efficient than the DT scheme when the relay is located near the sources. Additionally, algorithms that optimise relay positioning are developed based on two criteria - minimising total transmission delays and minimising total energy consumption subject to node location and power allocation constraints. This optimisation can be considered as a benchmark for relay positioning in either a low-latency or a low-energy-consumption WNCBN

    Estimation of cardiac output and pulmonary vascular resistance by contrast echocardiography transit time measurement: a prospective pilot study

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    Background Studies with other imaging modalities have demonstrated a relationship between contrast transit and cardiac output (CO) and pulmonary vascular resistance (PVR). We tested the hypothesis that the transit time during contrast echocardiography could accurately estimate both CO and PVR compared to right heart catheterization (RHC). Methods 27 patients scheduled for RHC had 2D-echocardiogram immediately prior to RHC. 3 ml of DEFINITY contrast followed by a 10 ml saline flush was injected, and a multi-cycle echo clip was acquired from the beginning of injection to opacification of the left ventricle. 2D-echo based calculations of CO and PVR along with the DEFINITY-based transit time calculations were subsequently correlated with the RHC-determined CO and PVR. Results The transit time from full opacification of the right ventricle to full opacification of the left ventricle inversely correlated with CO (r = -0.61, p \u3c 0.001). The transit time from peak opacification of the right ventricle to first appearance in the left ventricle moderately correlated with PVR (r = 0.46, p \u3c 0.01). Previously described echocardiographic methods for the determination of CO (Huntsman method) and PVR (Abbas and Haddad methods) did not correlate with RHC-determined values (p = 0.20 for CO, p = 0.18 and p = 0.22 for PVR, respectively). The contrast transit time method demonstrated reliable intra- (p \u3c 0.0001) and inter-observer correlation (p \u3c 0.001). Conclusions We describe a novel method for the quantification of CO and estimation of PVR using contrast echocardiography transit time. This technique adds to the methodologies used for noninvasive hemodynamic assessment, but requires further validation to determine overall applicability

    Clinical significance of left atrial anatomic abnormalities identified by cardiac computed tomography

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    Purpose: The clinical significance of newly identified left atrial anatomic abnormalities (LAAA)— accessory appendages, diverticula, septal pouches—by multidetector CT (MDCT) remains unclear. Similar anatomical outpouchings, i.e., the left atrial appendage, have been associated with cardioembolisms and arrhythmia. To test the hypothesis that LAAA are also associated with increased risk of these events, we performed a retrospective analysis to examine the association of LAAA in patients undergoing CT with embolic events and arrhythmia. Methods: 242 patients (mean age 56 SD 12 years, 41% female) were selected who had CT coronary angiography performed with 64-row MDCT between 2007 and 2012 if complete clinical history records were available. CT images were independently reviewed for the presence of LAAA. Association of cerebrovascular accident (CVA) or transient ischemic attack (TIA), atrial fibrillation, and palpitations to LAAA was calculated using odds ratios (OR) with 95% confidence interval (CI) and Fisher’s exact test. Results: After adjusting for age, sex, hypertension, dyslipidemia and diabetes via multiple logistic regression, patients with accessory appendages are more likely to have reported palpitations (OR: 1.80; CI: 1.03 - 3.16). Patients with diverticula and septal pouches are significantly older than those without these abnormalities (p = 0.01 and p = 0.02, respectively). Septal pouches are associated with diabetes (OR: 2.29; 95%CI: 1.15 - 4.54). Conclusions: Accessory left atrial appendages are associated with palpitations. Patients with septal pouches and diverticula are significantly older than those patients without these anatomic abnormalities, suggesting age dependency of these findings. None of these anatomic abnormalities were associated with thromboembolic events after adjustment for potentially confounding comorbidities

    Evaluation of pressure transmission and intra-aneurysmal contents after endovascular repair using the Trivascular Enovus expanded polytetrafluoroethylene stent graft in a canine model of abdominal aortic aneurysm

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    ObjectiveEndotension has been defined as persistently increased pressure within the excluded sac of an abdominal aortic aneurysm (AAA) resulting in increasing aneurysm size after endovascular repair in the absence of endoleak. Devices that use expanded polytetrafluoroethylene (ePTFE) have been associated with the development of endotension and continued AAA enlargement. In this study, intra-aneurysmal pressure and aneurysm content were evaluated after endovascular repair with the Enovus ePTFE stent graft in a canine model.MethodsProsthetic ePTFE aneurysms, each containing a solid-state, strain-gauge pressure transducer, were implanted in the infrarenal aorta of 13 mongrel dogs (25-35 kg). A second pressure transducer was inserted into the native aorta for systemic arterial pressure measurement. The stent graft was then deployed to exclude the aneurysm via distal aortic access. Comparison was made among three distinct stent grafts: the Trivascular Enovus (nonporous ePTFE; four animals), the original Gore Excluder (porous ePTFE; five animals), and the Medtronic AneuRx (Dacron; four animals). Daily systemic and intra-AAA pressures were measured for 4 weeks. Intra-aneurysmal pressures were indexed to simultaneously measured systemic pressures. After 4 weeks, the aorta, the prosthetic aneurysm, and its contents were harvested, photographed, and processed for histologic investigation with hematoxylin and eosin and Masson trichrome staining.ResultsWithin 24 hours after exclusion, the mean arterial pressure and pulse pressure within the AAA sac tapered to less than 20% of systemic pressure for all three stent graft types. Throughout the postoperative period, significantly lower indexed intra-aneurysmal pressures were present in the Enovus- and AneuRx-treated aneurysms as compared with those treated with the original Excluder stent graft (0.05 ± 0.04, 0.16 ± 0.06, and 0.06 ± 0.03 for the Enovus, Excluder, and AneuRx, respectively). Histologic analysis of the Enovus-treated aneurysms demonstrated intraluminal content characterized almost entirely by erythrocytes and infrequent white blood cells without the fibrin organization—characteristics of acute or chronic thrombus. This contrasted with the content of the Excluder-treated aneurysms, which contained poorly organized fibrin deposition suggestive of acute thrombus, and of the AneuRx-treated aneurysms, which demonstrated mature, well-organized collagenous connective tissue.ConclusionsExclusion of the AAA with the Enovus stent graft resulted in nearly complete elimination of intra-aneurysmal pressure in this model. Histologic analysis of the aneurysm content further suggested complete exclusion, including elimination of circulating clotting factors and fibroblasts responsible for thrombus formation and reorganization. Ultimately, clinical evaluation will be necessary to demonstrate the effectiveness of this stent graft in preventing the development of endotension.Clinical RelevanceEndovascular aneurysm repair is an effective method for the treatment of abdominal aortic aneurysm (AAA) subjected to the unique complications of endoleak and endotension, the indirect pressurization of a sac in the absence of endoleak. In our model, AAA exclusion with the Enovus stent graft results in inhibition of fluid and serum transudation into the AAA sac, a corresponding prompt pressure decay profile, and near-complete elimination of intra-aneurysmal pressure. With the advent of implantable wireless pressure transducers, this research can be readily translated to the clinical setting. Future intraoperative and postoperative studies may help elucidate the clinical significance of pressure decay profiles in identifying successful AAA exclusion and monitoring for the development of endotension and its clinical sequelae

    The reciprocal relationships between changes in adolescent perceived prevalence of smoking in movies and progression of smoking status

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    Smoking in movies is associated with adolescent smoking worldwide. To date, studies of the association mostly are restricted to the exposure to smoking images viewed by 9–15 year-olds. The association among older adolescents is rarely examined. In addition, the reciprocal effect of smoking behavior on subsequent reported exposure to smoking in movies has not been reported

    Overt ischemic colitis after endovascular repair of aortoiliac aneurysms

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    AbstractObjectiveControversy exists as to the cause of ischemic colitis complicating endovascular aneurysm repair. Occlusion of the hypogastric arteries (HAs) during endovascular repair of aortoiliac aneurysms (AIAs) results in a significant incidence of buttock claudication, and has been suggested as a causative factor in the development of postprocedural colonic ischemia, in addition to factors such as systemic hypotension, embolization of atheromatous debris, and interruption of inferior mesenteric artery inflow. To analyze the relationship between perioperative HA occlusion and postoperative ischemic colitis, we reviewed our experience over 2 years with Food and Drug Administration–approved endovascular graft devices for treatment of AIAs.MethodsElective repair of AIAs with bifurcated endovascular grafts was performed in 233 patients over a 2-year period. These included 184 AneuRx grafts, 17 Ancure grafts, and 32 Excluder grafts. During the experience, 44 patients (18.9%) underwent unilateral perioperative HA occlusion (28 right, 16 left) during the course of endovascular AIA repair, and 1 patient (0.4%) underwent bilateral HA occlusion.ResultsIn 4 patients (1.7%) signs and symptoms of ischemic colitis developed 2.0 ± 1.4 days postoperatively. In all patients the diagnosis was confirmed at sigmoidoscopy, and initial treatment included bowel rest, hydration, and intravenous antibiotic agents. Three patients with bilateral patent HAs required colonic resection 14.7 ± 9.7 days after the initial diagnosis, and 2 of these 3 patients died in the postoperative period. Pathologic findings confirmed the presence of atheroemboli in the colonic vasculature in all 3 patients who underwent colonic resection. The fourth patient had undergone multiple manipulations of the left HA in an unsuccessful attempt to preserve patency of this vessel during AIA repair. This patient recovered completely with nonoperative management. Perioperative unilateral HA occlusion was not associated with a significantly higher incidence of postoperative ischemic colitis.ConclusionPerioperative HA occlusion during aortoiliac open or endovascular surgery may contribute to development of the rare but potentially lethal complication of ischemic colitis. However, our extensive experience suggests that embolization of atheromatous debris to the HA tissue beds during endovascular manipulations, rather than proximal HA occlusion, is the primary cause of clinically significant ischemic colitis after endovascular aneurysm repair

    Prevalence of smoking in movies as perceived by teenagers: Longitudinal trends and predictors

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    Smoking in movies is prevalent. However, use of content analysis to describe trends in smoking in movies has provided mixed results and has not tapped what adolescents actually perceive

    Coexistence of Merons with Skyrmions in the Centrosymmetric van der Waals Ferromagnet Fe5GeTe2

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    Fe5−x_{5-x}GeTe2_2 is a centrosymmetric, layered van der Waals (vdW) ferromagnet that displays Curie temperatures TcT_c (270-330 K) that are within the useful range for spintronic applications. However, little is known about the interplay between its topological spin textures (e.g., merons, skyrmions) with technologically relevant transport properties such as the topological Hall effect (THE), or topological thermal transport. Here, we show via high-resolution Lorentz transmission electron microscopy that merons and anti-meron pairs coexist with N\'{e}el skyrmions in Fe5−x_{5-x}GeTe2_2 over a wide range of temperatures and probe their effects on thermal and electrical transport. We detect a THE, even at room TT, that senses merons at higher TTs as well as their coexistence with skyrmions as TT is lowered indicating an on-demand thermally driven formation of either type of spin texture. Remarkably, we also observe an unconventional THE in absence of Lorentz force and attribute it to the interaction between charge carriers and magnetic field-induced chiral spin textures. Our results expose Fe5−x_{5-x}GeTe2_2 as a promising candidate for the development of applications in skyrmionics/meronics due to the interplay between distinct but coexisting topological magnetic textures and unconventional transport of charge/heat carriers.Comment: In press. Four figures in the main text. Includes SI file with 19 additional figure
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