529 research outputs found
Assessment of Left Atrial Deformation and Function by 2-Dimensional Speckle Tracking Echocardiography in Healthy Dogs and Dogs With Myxomatous Mitral Valve Disease
open7noBackground: The assessment of left atrial (LA) function by 2-dimensional speckle tracking echocardiography (STE) holds important clinical implications in human medicine. Few similar data are available in dogs. Objectives: To assess LA function by STE in dogs with and without myxomatous mitral valve disease (MMVD), analyzing LA areas, systolic function, and strain. Animals: One hundred and fifty dogs were divided according to the American College of Veterinary Internal Medicine classification of heart failure: 23 dogs in class A, 52 in class B1, 36 in class B2, and 39 in class C + D. Methods: Prospective observational study. Conventional morphologic and Doppler variables, LA areas, and STE-based LA strain analysis were performed in all dogs and results were compared among groups. Correlation analysis was carried out between LA STE variables and other echocardiographic variables. Results: Variability study showed good reproducibility for all the tested variables (coefficient of variation <16%). Left atrial areas, fractional area change, peak atrial longitudinal strain (PALS), peak atrial contraction strain, and contraction strain index (CSI) differed significantly between groups B2 and C + D and all the other groups (overall P < .001), whereas only PALS differed between groups B1 and A (P = .01). Left atrial areas increased with progression of the disease, whereas LA functional parameters decreased. Only CSI increased nonsignificantly from group A to group B1 and then progressively decreased. Thirty-one significant correlations (P < .001, r > .3) were found between conventional left heart echocardiographic variables and LA areas and strain variables. Conclusions and Clinical Importance: Left atrial STE analysis provides useful information on atrial function in the dog, highlighting a progressive decline in atrial function with worsening of MMVD.openBaron Toaldo, M; Romito, G.; Guglielmini, C.; Diana, A.; Pelle, N.G.; Contiero, B.; Cipone, M.Baron Toaldo, M; Romito, G.; Guglielmini, C.; Diana, A.; Pelle, N.G.; Contiero, B.; Cipone, M
Cor triatriatum sinister in a dog
This report describes the transthoracic and transesophageal echocardiographic features of cor triatriatum sinister in an asymptomatic 6-year-old male French bulldog. Although cor triatriatum sinister represents a well-known and widely described cardiac malformation in humans, its description in the canine population is rare. In this clinical case, non-invasive echocardiographic techniques were helpful in visualizing and characterizing the lesion, allowing a valuable assessment of the malformation, and its hemodynamic consequences
Chaotic dynamics in superconducting nanocircuits
The quantum kicked rotator can be realized in a periodically driven
superconducting nanocircuit. A study of the fidelity allows the experimental
investigation of exponential instability of quantum motion inside the Ehrenfest
time scale, chaotic diffusion and quantum dynamical localization. The role of
noise and the experimental setup to measure the fidelity is discussed as well.Comment: 4 pages, 4 figure
Prognostic value of echocardiographic indices of left atrial morphology and function in dogs with myxomatous mitral valve disease
Background: The prognostic relevance of left atrial (LA) morphological and functional variables, including those derived from speckle tracking echocardiography (STE), has been little investigated in veterinary medicine. Objectives: To assess the prognostic value of several echocardiographic variables, with a focus on LA morphological and functional variables in dogs with myxomatous mitral valve disease (MMVD). Animals: One-hundred and fifteen dogs of different breeds with MMVD. Methods: Prospective cohort study. Conventional morphologic and echo-Doppler variables, LA areas and volumes, and STE-based LA strain analysis were performed in all dogs. A survival analysis was performed to test for the best echocardiographic predictors of cardiac-related death. Results: Most of the tested variables, including all LA STE-derived variables were univariate predictors of cardiac death in Cox proportional hazard analysis. Because of strong correlation between many variables, only left atrium to aorta ratio (LA/Ao > 1.7), mitral valve E wave velocity (MV E vel > 1.3 m/s), LA maximal volume (LAVmax > 3.53 mL/kg), peak atrial longitudinal strain (PALS < 30%), and contraction strain index (CSI per 1% increase) were entered in the univariate analysis, and all were predictors of cardiac death. However, only the MV E vel (hazard ratio [HR], 4.45; confidence interval [CI], 1.76-11.24; P <.001) and LAVmax (HR, 2.32; CI, 1.10-4.89; P =.024) remained statistically significant in the multivariable analysis. Conclusions and Clinical Importance: The assessment of LA dimension and function provides useful prognostic information in dogs with MMVD. Considering all the LA variables, LAVmax appears the strongest predictor of cardiac death, being superior to LA/Ao and STE-derived variables
Reversible myocardial injury aggravated by complex arrhythmias in three Toxoplasma gondii-positive dogs
Although Toxoplasma gondii represents an oft-cited cause of myocarditis in veterinary medicine, the existing literature on the pre-mortem demonstration of T. gondii-associated myocardial injury (MI) in dogs is scant. In this case series, we provide detailed clinical, laboratory, echocardiographic and electrocardiographic description of three T. gondii-positive dogs diagnosed with MI. In all cases, etiological diagnosis was based on the antibody screening test (all dogs had IgM titres ≥1:64) and MI was demonstrated by a concomitant increase of the serum concentration of cardiac troponin I (0.25-9.6 ng/ml, upper hospital limit <0.15 ng/ml). In all dogs, MI was aggravated by complex arrhythmias (ventricular in two dogs, and either ventricular and supraventricular in the remaining dog). In one case, left ventricular systolic dysfunction was also present. All dogs underwent an extensive diagnostic work-up aimed at excluding additional comorbidities, either cardiac and extra-cardiac, possibly able to contribute to MI, arrhythmias and systolic dysfunction. All dogs received appropriate antiprotozoal (i.e., clindamycin) and antiarrhythmic (i.e., amiodarone, sotalol) therapy. This was systematically followed by a simultaneous decline in T. gondii serology titres, normalisation of troponin level and left ventricular systolic function, and the resolution of clinical and electrocardiographic abnormalities. In light of this result, therapies were interrupted and subsequent controls ruled out any disease relapse. In these cases, the clinical and instrumental findings obtained at admission and rechecks strongly supported the clinical suspicion of toxoplasmic myocarditis
Gender Differences: Smokers With and Without Substance Abuse History
poster abstractPrevious research suggests that individuals with chemical dependence history experience more
intense nicotine addiction, and during smoking cessation may be more likely to demonstrate
increased negative affect and unfavorable scores on psychometric assessments. It is unknown
how men and women may differ in their susceptibilities to such undesirable outcomes. From
1992-2004, The Indiana University Nicotine Dependence Program (IUNDP) treated over 1200
patients using a Mayo Clinic-based protocol which assesses the behavioral, social, and
physiological aspects of nicotine dependence. The IUNDP was instituted at Fairbanks Hospital’s
addictions center to address tobacco use among the patients and staff. Charts of individuals
who completed nicotine dependence treatment (1992-2011) were selected from IU School of
Dentistry and Fairbanks Hospital for retrospective analysis. Chart selection criteria consisted of
the availability of complete pre-and post quit measures for a minimum of four total appointments
and two post-quit appointments. Reviewed were 107 charts from patients without a history of
chemical dependence (ND) and 123 from those with a chemical dependence history (CD),
including 120 men and 110 women. Student researchers used a standardized protocol to
capture 16 tobacco use and demographic variables and 12 post-quit measures. Comparisons
between CD and ND groups were made using Pearson chi-square tests for binary data,
Wilcoxon rank sum tests for all other data, and Wilcoxon signed rank tests for changes between
time periods. Despite similarities among CD and ND smokers, males and females appear to
face distinct challenges. Results suggest CD males are significantly more negative in mood, and
are more likely to have increased withdrawal symptoms at the end of treatment. Males were
also more likely to experience adverse events with NRT. Both CD males and females
experienced more increased appetite than their ND counterparts. Females scored higher on
addiction-related sensorimotor manipulation and may have increased propensity for
psychological dependence
Standard and Null Weak Values
Weak value (WV) is a quantum mechanical measurement protocol, proposed by
Aharonov, Albert, and Vaidman. It consists of a weak measurement, which is
weighed in, conditional on the outcome of a later, strong measurement. Here we
define another two-step measurement protocol, null weak value (NVW), and point
out its advantages as compared to WV. We present two alternative derivations of
NWVs and compare them to the corresponding derivations of WVs.Comment: 11 pages, 2 figures. To appear in Quantum Theory: A Two-Time Success
Story: Yakir Aharonov Festschrif
Topological superconducting phases in disordered quantum wires with strong spin-orbit coupling
Zeeman fields can drive semiconductor quantum wires with strong spin-orbit
coupling and in proximity to s-wave superconductors into a topological phase
which supports end Majorana fermions and offers an attractive platform for
realizing topological quantum information processing. Here, we investigate how
potential disorder affects the topological phase by a combination of analytical
and numerical approaches. Most prominently, we find that the robustness of the
topological phase against disorder depends sensitively and non-monotonously on
the Zeeman field applied to the wire.Comment: 6 pages, 3 figures; published versio
Transport properties of a periodically driven superconducting single electron transistor
We discuss coherent transport of Cooper pairs through a Cooper pair shuttle.
We analyze both the DC and AC Josephson effect in the two limiting cases where
the charging energy is either much larger or much smaller than the
Josephson coupling . In the limit we present the detailed
behavior of the critical current as a function of the damping rates and the
dynamical phases. The AC effect in this regime is very sensitive to all
dynamical scales present in the problem. The effect of fluctuations of the
external periodic driving is discussed as well. In the opposite regime the
system can be mapped onto the quantum kicked rotator, a classically chaotic
system. We investigate the transport properties also in this regime showing
that the underlying classical chaotic dynamics emerges as an incoherent
transfer of Cooper pairs through the shuttle. For an appropriate choice of the
parameters the Cooper pair shuttle can exhibit the phenomenon of dynamical
localization. We discuss in details the properties of the localized regime as a
function of the phase difference between the superconducting electrodes and the
decoherence due to gate voltage fluctuations. Finally we point how dynamical
localization is reflected in the noise properties of the shuttle.Comment: 22 pages, 7 figures; v3 (published version): added references,
improved readabilit
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