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https://www.readbyqxmd.com/read/28857176/do-right-ventricular-trabeculae-gain-energetic-advantage-from-having-a-greater-velocity-of-shortening
#1
Toan Pham, June-Chiew Han, Andrew Taberner, Denis Loiselle
Our study aimed to ascertain whether the interventricular difference of shortening velocity, reported for isolated cardiac tissues in vitro, affects interventricular mechano-energetic performance when tested under physiological conditions using a shortening protocol designed to mimic those in vivo. We isolated trabeculae from both ventricles of the rat, mounted them in a calorimeter, and performed experiments at 37°C and 5 Hz stimulus frequency to emulate conditions of the rat heart in vivo. Each trabecula was subjected to two experimental protocols: (i) isotonic work-loop contractions at a variety of afterloads, and (ii) isometric contractions at a variety of preloads...
August 30, 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
#2
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/cardio-pulmonary-interactions-physiologic-basis-and-clinical-applications
#3
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, pulmonary vascular resistance, and can compress the heart in the cardiac fossa; 3) spontaneous inspiratory efforts decrease intrathoracic pressure (ITP) increasing venous return and impeding left ventricular (LV) ejection; whereas positive pressure ventilation decreases venous return and unloads LV ejection. Spontaneous inspiratory efforts may induce acute LV failure and cardiogenic pulmonary edema...
August 18, 2017: 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
#4
Junjing Su, Charlotte Manisty, Ulf Simonsen, Luke S Howard, Kim H Parker, Alun D Hughes
Detailed hemodynamic analysis may provide novel insights into the pulmonary circulation. Therefore, wave intensity and reservoir-excess pressure analyses were applied in the pulmonary artery to characterise changes in wave propagation and reservoir function during spontaneous respiration and dynamic stress tests. Right heart catheterisation was performed using a pressure and Doppler flow sensor tipped guidewire to obtain simultaneous pressure and flow velocity measurements in the pulmonary artery in control subjects and patients with pulmonary arterial hypertension (PAH) at rest...
August 17, 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
#5
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...
June 28, 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
#6
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...
June 28, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28560812/threshold-position-control-of-anticipation-in-humans-a-possible-role-of-corticospinal-influences
#7
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
#8
Paolo T Pianosi, Eric Emerling, Kristin C Mara, Amy L Weaver, Philip 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 (VO2 ) was measured breath-by-breath at rest and during cycle ergometry, while cardiac output was measured by acetylene rebreathing at rest plus 2-3 sub-threshold workloads...
May 24, 2017: 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
#9
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
#10
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 31, 2017: Heart, Lung & Circulation
https://www.readbyqxmd.com/read/28407402/cirrhotic-cardiomyopathy-implications-for-liver-transplantation
#11
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
#12
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
https://www.readbyqxmd.com/read/28117941/donor-preconditioning-after-the-onset-of-brain-death-with-dopamine-derivate-n-octanoyl-dopamine-improves-early-posttransplant-graft-function-in-the-rat
#13
S Li, S Korkmaz-Icöz, T Radovits, M Ruppert, R Spindler, S Loganathan, P Hegedűs, P Brlecic, B Theisinger, S Theisinger, S Höger, M Brune, F Lasitschka, M Karck, B Yard, G Szabó
Heart transplantation is the therapy of choice for end-stage heart failure. However, hemodynamic instability, which has been demonstrated in brain-dead donors (BDD), could also affect the posttransplant graft function. We tested the hypothesis that treatment of the BDD with the dopamine derivate n-octanoyl-dopamine (NOD) improves donor cardiac and graft function after transplantation. Donor rats were given a continuous intravenous infusion of either NOD (0.882 mg/kg/h, BDD+NOD, n = 6) or a physiological saline vehicle (BDD, n = 9) for 5 h after the induction of brain death by inflation of a subdural balloon catheter...
July 2017: American Journal of Transplantation
https://www.readbyqxmd.com/read/28116751/cardiac-sympathetic-afferent-reflex-control-of-cardiac-function-in-normal-and-chronic-heart-failure-states
#14
Han-Jun Wang, George J Rozanski, Irving H Zucker
KEY POINTS: Cardiac sympathetic afferents are considered to be essential pathways for transmission of cardiac nociception to the central nervous system during myocardial ischaemia. However, a potential contribution of the CSAR control of cardiac dysfunction in both normal and chronic heart failure (CHF) states remains unknown. We found that activation of the CSAR evokes little increase in cardiac contractility with an exaggerated peripheral vasoconstriction in the CHF state. CSAR inhibition by epicardial lidocaine decreased cardiac contractility to a greater extent in CHF rats than sham rats...
April 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28098356/mechano-chemo-transduction-in-cardiac-myocytes
#15
Ye Chen-Izu, Leighton T Izu
The heart has the ability to adjust to changing mechanical loads. The Frank-Starling law and the Anrep effect describe exquisite intrinsic mechanisms the heart has for autoregulating the force of contraction to maintain cardiac output under changes of preload and afterload. Although these mechanisms have been known for more than a century, their cellular and molecular underpinnings are still debated. How does the cardiac myocyte sense changes in preload or afterload? How does the myocyte adjust its response to compensate for such changes? In cardiac myocytes Ca(2+) is a crucial regulator of contractile force and in this review we compare and contrast recent studies from different labs that address these two important questions...
June 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/27885445/limited-ventricular-preload-is-the-main-reason-for-reduced-stress-reserve-after-atrial-baffle-repair
#16
Andreas Eicken, Julia Michel, Alfred Hager, Daniel Tanase, Harald Kaemmerer, Julie Cleuziou, John Hess, Peter Ewert
The atrial baffle repair (ABR) significantly improved the fate of patients with transposition of the great arteries (TGA). However, these patients show impaired exercise tolerance and some present severe decline of systemic ventricular function. Intrinsic myocardial weakness, low heart rate response to exercise and diastolic filling impairment are discussed to be causative. Forty-nine long-term survivors with TGA (median age 23.7 year) after ABR were catheterized with measured oxygen consumption in four conditions (baseline, volume, atrial pacing, dobutamine) and the results were compared to 10 normal controls...
February 2017: Pediatric Cardiology
https://www.readbyqxmd.com/read/27816583/magneto-controlled-aptasensor-for-simultaneous-electrochemical-detection-of-dual-mycotoxins-in-maize-using-metal-sulfide-quantum-dots-coated-silica-as-labels
#17
Chengquan Wang, Jing Qian, Keqi An, Xingyi Huang, Lufang Zhao, Qian Liu, Nan Hao, Kun Wang
Currently there is an urgent need for multi-mycotoxin detection methods due to the co-occurrence of multiple mycotoxins in food raw materials and their augmented toxicity. Herein, a magneto-controlled aptasensor has been developed for simultaneous electrochemical detection of ochratoxin A (OTA) and fumonisin B1 (FB1), two typical mycotoxins found in food crops world-wide. This aptasensor was designed using the high specificity between the target and aptamer with heavy CdTe or PbS quantum dots (QDs) coated silica as labels and the complementary DNA functionalized magnetic beads as capture probes...
March 15, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/27754006/js-ish-esh-2-update-on-the-detection-and-follow-up-of-early-hypertensive-heart-disease
#18
Enrico Agabiti Rosei
Current Hypertension Guidelines emphasize the importance of assessing the presence of preclinical organ damage. In fact, an extensive evaluation of organ damage may increase the number of patients classified at high CV risk and therefore strongly influence the clinical management of patients. Hypertensive heart disease remains to date the form of organ damage for which there is the greatest amount of evidence of a strong independent prognostic significance. In the presence of a chronic pressure overload, a parallel addition of sarcomers takes place with an increase in myocyte width, which in turn increases left ventricular wall thickness; myocyte hypertrophy is also associated with apoptosis, collagen deposition and ventricular fibrosis with an impairment of coronary hemodynamics as well, thus profoundly influencing functional properties of the left (and right) ventricle...
September 2016: Journal of Hypertension
https://www.readbyqxmd.com/read/27744267/ventricular-vascular-dynamics-in-pediatric-patients-with-heart-failure-and-preserved-ejection-fraction
#19
Satoshi Masutani, Seiko Kuwata, Clara Kurishima, Yoichi Iwamoto, Hirofumi Saiki, Masaya Sugimoto, Hirotaka Ishido, Hideaki Senzaki
OBJECTIVE: The details of the ventricular-vascular dynamics of heart failure with preserved ejection fraction (HFpEF) in children remain poorly understood. We tested the hypothesis that pediatric HFpEF patients have ventricular systolic, diastolic, and arterial stiffening at rest as well as impaired reserve function associated with coronary supply/demand imbalance. METHODS: We studied the ventricular pressure-area relationship in 22 pediatric HFpEF patients and 22 control subjects before and after dobutamine infusion and during abdominal compression...
December 15, 2016: International Journal of Cardiology
https://www.readbyqxmd.com/read/27642917/js-ish-esh-2-update-on-the-detection-and-follow-up-of-early-hypertensive-heart-disease
#20
Enrico Agabiti Rosei
Current Hypertension Guidelines emphasize the importance of assessing the presence of preclinical organ damage. In fact, an extensive evaluation of organ damage may increase the number of patients classified at high CV risk and therefore strongly influence the clinical management of patients. Hypertensive heart disease remains to date the form of organ damage for which there is the greatest amount of evidence of a strong independent prognostic significance. In the presence of a chronic pressure overload, a parallel addition of sarcomers takes place with an increase in myocyte width, which in turn increases left ventricular wall thickness; myocyte hypertrophy is also associated with apoptosis, collagen deposition and ventricular fibrosis with an impairment of coronary hemodynamics as well, thus profoundly influencing functional properties of the left (and right) ventricle...
September 2016: Journal of Hypertension
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