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https://www.readbyqxmd.com/read/29748312/noninvasive-assessment-of-preload-reserve-enhances-risk-stratification-of-patients-with-heart-failure-with-reduced-ejection-fraction
#1
Kensuke Matsumoto, Akira Onishi, Hirotsugu Yamada, Kenya Kusunose, Makiko Suto, Yutaka Hatani, Hiroki Matsuzoe, Kazuhiro Tatsumi, Hidekazu Tanaka, Ken-Ichi Hirata
BACKGROUND: The leg-positive pressure maneuver can safely and noninvasively apply preload stress without increase in total body fluid volume. The purpose of this study was to determine whether preload stress could be useful for risk stratification of patients with heart failure with reduced ejection fraction. METHODS AND RESULTS: For this study, 120 consecutive patients with heart failure with reduced ejection fraction were prospectively recruited. The stroke work index was estimated as product of stroke volume index and mean blood pressure, and the E/e' ratio was calculated to estimate ventricular filling pressure...
May 2018: Circulation. Cardiovascular Imaging
https://www.readbyqxmd.com/read/29727215/acute-stimulation-of-the-soluble-guanylate-cyclase-does-not-impact-on-left-ventricular-capacitance-in-normal-and-hypertrophied-porcine-hearts-in-vivo
#2
Alessio Alogna, Michael Schwarzl, Martin Manninger, Nazha Hamdani, Birgit Zirngast, Benjamin Kloth, Paul Steendijk, Jochen Verderber, David Zweiker, Dirk Westermann, Stefan Blankenberg, Heinrich Maechler, Carsten Tschöpe, Wolfgang A Linke, Gunther Marsche, Burkert M Pieske, Heiner Post
Experimental data indicate that stimulation of the nitric oxide (NO) - soluble guanylate cyclase (sGC) - cyclic guanosine monophosphate (cGMP) - protein kinase G (PKG) pathway can increase left ventricular (LV) capacitance via phosphorylation of the myofilamental protein titin. We aimed to test whether acute pharmacological sGC stimulation with BAY 41-8543 would increase LV capacitance via titin phosphorylation in healthy and deoxycorticosteroneacetate (DOCA)-induced hypertensive pigs. Nine healthy, landrace pigs and seven pigs with DOCA-induced hypertension and LV concentric hypertrophy were acutely instrumented to measure LV end-diastolic pressure-volume-relationships (EDPVR) at baseline and during intravenous infusion of BAY 41-8543 (1 and 3 μg/kg/min for 30 min, respectively)...
May 4, 2018: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29623416/agreement-between-preload-reserve-measured-by-impedance-cardiography-and-echocardiography-during-pregnancy
#3
Huan Liang, Åse Vårtun, Ganesh Acharya
PURPOSE: Accurate assessment of cardiac function is important during pregnancy. Echocardiography and impedance cardiography (ICG) are commonly used noninvasive methods to measure stroke volume (SV) and cardiac output (CO). The difference in stroke volume (ΔSV) or cardiac output (ΔCO) measured at baseline and after passive leg raising (PLR) is a measure of preload reserve that predicts volume responsiveness. However, the agreement between these two methods in measuring preload reserve during pregnancy is unclear...
April 5, 2018: Archives of Gynecology and Obstetrics
https://www.readbyqxmd.com/read/29502350/postprandial-glucose-lowering-effect-of-premeal-consumption-of-protein-enriched-dietary-fiber-fortified-bar-in-individuals-with-type-2-diabetes-mellitus-or-normal-glucose-tolerance
#4
Jae Hyun Bae, Lee Kyung Kim, Se Hee Min, Chang Ho Ahn, Young Min Cho
AIMS/INTRODUCTION: Protein preload improves postprandial glycemia by stimulating secretion of insulin and incretin hormones. However, it requires a large dose of protein to produce a significant effect. The present study was carried out to investigate the postprandial glucose-lowering effect of a premeal protein-enriched, dietary fiber-fortified bar (PFB), which contains moderate amounts of protein, in individuals with type 2 diabetes mellitus or normal glucose tolerance (NGT). MATERIALS AND METHODS: The participants (15 type 2 diabetes mellitus and 15 NGT) were randomly assigned to either a premeal or postmeal PFB group and underwent two mixed meal tolerance tests, 1 week apart in reverse order...
March 4, 2018: Journal of Diabetes Investigation
https://www.readbyqxmd.com/read/29449367/load-independent-systolic-and-diastolic-right-ventricular-function-in-heart-failure-with-preserved-ejection-fraction-as-assessed-by-resting-and-handgrip-exercise-pressure-volume-loops
#5
Karl-Philipp Rommel, Maximilian von Roeder, Christian Oberueck, Konrad Latuscynski, Christian Besler, Stephan Blazek, Thomas Stiermaier, Karl Fengler, Volker Adams, Marcus Sandri, Axel Linke, Gerhard Schuler, Holger Thiele, Philipp Lurz
BACKGROUND: Although systolic right ventricular (RV) dysfunction has been shown to be a potent predictor for adverse outcomes in patients with heart failure with preserved ejection fraction (HFpEF), RV functional abnormalities in the course of the syndrome are not well characterized. We, therefore, sought to assess load-independent and load-dependent systolic and diastolic characteristics of RV function in stable outpatients with HFpEF. METHODS AND RESULTS: We invasively obtained RV and left ventricular pressure-volume loops in 24 HFpEF patients and 9 patients without heart failure symptoms with a conductance catheter during basal conditions and handgrip exercise...
February 2018: Circulation. Heart Failure
https://www.readbyqxmd.com/read/29431237/contribution-of-facet-joints-axial-compression-and-composition-to-human-lumbar-disc-torsion-mechanics
#6
Semih E Bezci, Ananth Eleswarapu, Eric O Klineberg, Grace D O'Connell
Stresses applied to the spinal column are distributed between the intervertebral disc and facet joints. Structural and compositional changes alter stress distributions within the disc and between the disc and facet joints. These changes influence the mechanical properties of the disc joint, including its stiffness, range of motion, and energy absorption under quasi-static and dynamic loads. There have been few studies evaluating the role of facet joints in torsion. Furthermore, the relationship between biochemical composition and torsion mechanics is not well understood...
February 12, 2018: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
https://www.readbyqxmd.com/read/29349824/reduced-left-ventricular-filling-following-blood-volume-extraction-does-not-result-in-compensatory-augmentation-of-cardiac-mechanics
#7
Rachel Lord, David MacLeod, Keith George, David Oxborough, Rob Shave, Mike Stembridge
NEW FINDINGS: What is the central question of this study? A reduction in left ventricular (LV) filling, and concomitant increase in heart rate, augments LV mechanics to maintain stroke volume (SV); however, the impact of reduced LV filling in isolation on SV and LV mechanics is currently unknown. What is the main finding and its importance? An isolated decrease in LV filling did not provoke a compensatory increase in mechanics to maintain SV; in contrast, LV mechanics and SV were reduced...
April 1, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29297963/matrix-approach-to-the-simultaneous-detection-of-multiple-potato-pathogens-by-real-time-pcr
#8
M M Nikitin, N V Statsyuk, P A Frantsuzov, V G Dzhavakhiya, A G Golikov
AIM: Create a method for highly sensitive, selective, rapid and easy-to-use detection and identification of economically significant potato pathogens, including viruses, bacteria and oomycetes, be it single pathogen, or a range of various pathogens occurring simultaneously. METHODS AND RESULTS: Test-systems for real-time PCR, operating in the unified amplification regime, have been developed for Phytophthora infestans, Pectobacterium atrosepticum, Dickeya dianthicola, Dickeya solani, Ralstonia solanacearum, Pectobacterium carotovorum, Clavibacter michiganensis subsp...
March 2018: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/28857176/do-right-ventricular-trabeculae-gain-energetic-advantage-from-having-a-greater-velocity-of-shortening
#9
Toan Pham, June-Chiew Han, Andrew Taberner, Denis Loiselle
KEY POINTS: We designed a study to test whether velocity of shortening in right-ventricular tissue preparations is greater than that of the left side under conditions mimicking those encountered by the heart in vivo. Our experiments allowed us to explore whether greater velocity of shortening results in any energetic advantage. We found that velocity of shortening was higher in the rat right-ventricular trabeculae. These results at the tissue level seem paradoxical to the velocity of ventricular ejection at the organ level, and are not always in accord with shortening of unloaded cells...
October 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28843329/safety-and-feasibility-of-the-transcatheter-approach-to-create-a-reverse-potts-shunt-in-children-with-idiopathic-pulmonary-arterial-hypertension
#10
Younes Boudjemline, Aleksander Sizarov, Sophie Malekzadeh-Milani, Cristian Mirabile, Marien Lenoir, Diala Khraiche, Marilyne Lévy, Damien Bonnet
BACKGROUND: The reversed Potts shunt improves right ventricular (RV) function in patients with suprasystemic pulmonary arterial hypertension (PAH). The proximity of the left pulmonary artery (LPA) to the descending aorta (DAo) permits the creation of a transcatheter connection. We sought to assess the safety, feasibility, and hemodynamic efficacy of the transcatheter Potts shunt (TPS) in children. METHODS: The TPS procedure was performed using radiofrequency energy for vessel perforation and deployment of a covered stent to connect the DAo and LPA...
September 2017: Canadian Journal of Cardiology
https://www.readbyqxmd.com/read/28820609/cardiopulmonary-interactions-physiologic-basis-and-clinical-applications
#11
Michael R Pinsky
The hemodynamic effects of ventilation can be grouped into three concepts: 1) Spontaneous ventilation is exercise; 2) changes in lung volume alter autonomic tone and pulmonary vascular resistance and can compress the heart in the cardiac fossa; and 3) spontaneous inspiratory efforts decrease intrathoracic pressure, increasing venous return and impeding left ventricular ejection, whereas positive-pressure ventilation decreases venous return and unloads left ventricular ejection. Spontaneous inspiratory efforts may induce acute left ventricular failure and cardiogenic pulmonary edema...
February 2018: Annals of the American Thoracic Society
https://www.readbyqxmd.com/read/28816352/pulmonary-artery-wave-propagation-and-reservoir-function-in-conscious-man-impact-of-pulmonary-vascular-disease-respiration-and-dynamic-stress-tests
#12
Junjing Su, Charlotte Manisty, Ulf Simonsen, Luke S Howard, Kim H Parker, Alun D Hughes
KEY POINTS: Wave travel plays an important role in cardiovascular physiology. However, many aspects of pulmonary arterial wave behaviour remain unclear. Wave intensity and reservoir-excess pressure analyses were applied in the pulmonary artery in subjects with and without pulmonary hypertension during spontaneous respiration and dynamic stress tests. Arterial wave energy decreased during expiration and Valsalva manoeuvre due to decreased ventricular preload. Wave energy also decreased during handgrip exercise due to increased heart rate...
October 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28659550/significant-prognostic-value-of-acute-preload-stress-echocardiography-using-leg-positive-pressure-maneuver-for-patients-with-symptomatic-severe-aortic-stenosis-awaiting-aortic-valve-intervention
#13
Hiroki Matsuzoe, Kensuke Matsumoto, Hidekazu Tanaka, Yutaka Hatani, Keiko Hatazawa, Hiroyuki Shimoura, Junichi Ooka, Hiroyuki Sano, Keiko Ryo-Koriyama, Toshiro Shinke, Hirotsugu Yamada, Yutaka Okita, Ken-Ichi Hirata
BACKGROUND: Although aortic valve intervention is recommended for virtually all symptomatic patients with aortic stenosis (AS), how urgently the intervention should be performed remains controversial. The aim of this study was thus to determine whether the preload reserve in response to leg-positive pressure (LPP) maneuver could serve for decision-making for AS patients awaiting aortic valve intervention.Methods and Results:Sixty-eight patients with symptomatic AS, who were referred for aortic valve intervention, were recruited...
November 24, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
https://www.readbyqxmd.com/read/28657130/a-compact-and-facile-microfluidic-droplet-creation-device-using-a-piezoelectric-diaphragm-micropump-for-droplet-digital-pcr-platforms
#14
Naoaki Okura, Yuta Nakashoji, Toshihiro Koshirogane, Masaki Kondo, Yugo Tanaka, Kohei Inoue, Masahiko Hashimoto
We have exploited a compact and facile microfluidic droplet creation device consisting of a poly(dimethylsiloxane) microfluidic chip possessing T-junction channel geometry, two inlet reservoirs, and one outlet reservoir, and a piezoelectric (PZT) diaphragm micropump with controller. Air was evacuated from the outlet reservoir using the PZT pump, reducing the pressure inside. The reduced pressure within the outlet reservoir pulled oil and aqueous solution preloaded in the inlet reservoirs into the microchannels, which then merged at the T-junction, successfully forming water-in-oil emulsion droplets at a rate of ∼1000 per second with minimal sample loss...
October 2017: Electrophoresis
https://www.readbyqxmd.com/read/28560812/threshold-position-control-of-anticipation-in-humans-a-possible-role-of-corticospinal-influences
#15
Lei Zhang, Nicolas A Turpin, Anatol G Feldman
KEY POINTS: Sudden unloading of preloaded wrist muscles elicits motion to a new wrist position. Such motion is prevented if subjects unload muscles using the contralateral arm (self-unloading). Corticospinal influences originated from the primary motor cortex maintain tonic influences on motoneurons of wrist muscles before sudden unloading but modify these influences prior to the onset and until the end of self-unloading. Results are interpreted based on the previous finding that intentional actions are caused by central, particularly corticospinal, shifts in the spatial thresholds at which wrist motoneurons are activated, thus predetermining the attractor point at which the neuromuscular periphery achieves mechanical balance with environment forces...
August 1, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28543923/sex-differences-in-fitness-and-cardiac-function-during-exercise-in-adolescents-with-chronic-fatigue
#16
P T Pianosi, E Emerling, K C Mara, A L Weaver, P R Fischer
Females demonstrate less robust Frank-Starling mechanism with respect to cardiac preload than males at rest. We asked whether this phenomenon would also affect cardiac performance during exercise. We hypothesized that stroke volume (SV) response to exercise would be more limited in deconditioned females such that cardiac output would be mainly rate dependent, compared with males. We conducted a chart audit of clinical exercise tests performed by adolescents with chronic fatigue. Oxygen uptake (V˙O2) was measured breath-by-breath at rest and during cycle ergometry, while cardiac output was measured by acetylene rebreathing at rest plus 2-3 subthreshold workloads...
February 2018: Scandinavian Journal of Medicine & Science in Sports
https://www.readbyqxmd.com/read/28528579/phosphodiesterase-type-5-inhibition-may-reduce-diastolic-function-in-women-with-ischemia-but-no-obstructive-coronary-artery-disease
#17
Michael D Nelson, Puja K Mehta, Janet Wei, Behzad Sharif, Louise E J Thomson, Daniel Berman, Debiao Li, C Noel Bairey Merz
BACKGROUND: Ischemia, in the absence of obstructive coronary artery disease, is prevalent in women, and associated with increased risk for major cardiovascular events. Coronary microvascular dysfunction is prevalent in these patients, and associated with impaired diastolic function. Despite our general understanding, however, optimal treatment of this cohort remains elusive. METHODS: To address this knowledge gap, we performed an open-label treatment trial to assess whether phosphodiesterase type 5 inhibition improves coronary microvascular perfusion and diastolic function in women with signs and symptoms of ischemia but no evidence of obstructive coronary artery disease...
May 22, 2017: Journal of Medical Case Reports
https://www.readbyqxmd.com/read/28522275/impact-of-continuous-positive-airway-pressure-on-left-ventricular-systolic-loading-and-coronary-flow-reserve-in-healthy-young-men
#18
Volker Schulze, Christian Meyer, Christian Eickholt, Roberto Sansone, Stefanie Keymel, Christian Heiss, Tienush Rassaf, Malte Kelm, Stephan Steiner
BACKGROUND: Increased augmentation index (AIx) is accompanied by an elevated cardiovascular risk. A reduction of AIx is known for long-term continuous positive airway pressure (CPAP) therapy. We hypothesised that acute preload and left ventricular workload effects AIx and subendocardial viability ratio (SEVR) as a marker of coronary flow reserve. METHODS: Increased augmentation index and central blood pressure parameters were measured by radial artery tonometry in 17 healthy men (32/±6years) at rest and during CPAP ventilation at pressures of 5, 10mbar and after recovery...
March 2018: Heart, Lung & Circulation
https://www.readbyqxmd.com/read/28407402/cirrhotic-cardiomyopathy-implications-for-liver-transplantation
#19
REVIEW
Hongqun Liu, Saumya Jayakumar, Mouhieddin Traboulsi, Samuel S Lee
The majority of patients on a waiting list for liver transplantation have end-stage liver disease. Because of the marked peripheral vasodilatation of end-stage cirrhosis that masks a latent myocardial dysfunction, cardiac abnormalities in the resting state are usually subclinical and escape the attention of physicians. However, when challenged, the systolic and diastolic contractile responses are attenuated. In addition to these contractile abnormalities, morphological changes, such as enlargement or hypertrophy of cardiac chambers, and electrophysiological repolarization changes, including a prolonged QT interval, can be observed...
June 2017: Liver Transplantation
https://www.readbyqxmd.com/read/28195341/left-ventricular-systolic-function-is-associated-with-sympathetic-nervous-activity-and-markers-of-inflammation-in-cirrhosis
#20
COMPARATIVE STUDY
Raquel Yotti, Cristina Ripoll, Yolanda Benito, Maria Vega Catalina, Jaime Elízaga, Diego Rincón, Francisco Fernández-Avilés, Javier Bermejo, Rafael Bañares
An accurate evaluation of cardiac function in patients with cirrhosis remains a challenge. We used robust echocardiographic indices to characterize left ventricular (LV) systolic function and its relationship to activation of the sympathetic nervous system and inflammation in 59 patients with cirrhosis and 59 age-matched controls. Additionally, in 11 patients we withdrew beta-blockers and diuretics and used phenylephrine and albumin infusion to evaluate the response to acute afterload and preload changes (interventional substudy)...
June 2017: Hepatology: Official Journal of the American Association for the Study of Liver Diseases
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