100 research outputs found
Diagnostic performance of P wave duration in the identification of left atrial enlargement in dogs
No full textObjectives: To determine sensitivity and specificity of P wave duration in the identification of left atrial enlargement (LAE) in dogs.
Methods: Electrocardiograms (ECG) from normal dogs and dogs with various cardiovascular diseases were evaluated. Inclusion criteria were the availability of an ECG showing a stable isoelectric line, easily recognizable P waves and good quality 2D echocardiographic estimate of left atrial dimensions using the left atrial to aortic root ratio (LA/Ao).
Using a metal caliper system, P wave duration was measured to the nearest 10 msec for six consecutive heart beats; data were then averaged for each dog. The accuracy of P wave duration in predicting LAE was determined using a Receiver Operating Characteristic (ROC) analysis.
Results: 156 dogs were included in the study. Average P wave durations of 20, 30, 40 and 50 msec yielded sensitivities of 100%, 85%, 68% and 40% and specificities of 0%, 16.04%,
64.15% and 93.4%, respectively, for the diagnosis of LAE by echocardiography. The estimated Area Under Curve (AUC) of the ROC curve was 0.70 (95% confidence interval: 0.60-0.80).
Clinical significance: The diagnostic performance of P wave duration for identification of LAE in dogs presents considerable limitations
Holter monitoring in dogs with mitral regurgitation and different class of heart failure
No full textEcho-assisted percutaneous renal biopsy in dogs. A retrospective study of 229 cases
No full textRenal biopsies were carried out on 229 dogs using an echo-assisted, semi-automatic method. Complications arising after the biopsy were also evaluated. The biopsies were examined for the accuracy of diagnosis and the presence of histologically demonstrable primary renal pathologies. A retrospective study of the observed lesions and parenchymal echogenicity showed a correlation between these factors involving the tubulo-interstitial compartment. Histopathological renal lesions and their correlation with laboratory methods are the only parameters that allow a correct diagnostic, prognostic, and therapeutic work-up in cases of clinical kidney disease in canines. © 2003 Elsevier Ltd. All rights reserved
Health-monitoring of a jamming-tolerant electromechanical actuator with differential ball screws
No full textThe paper deals with the theoretical and experimental development of model-based health-monitoring
algorithms for a jamming-tolerant electromechanical actuator for flight control applications. A nonlinear dynamic model of the actuator, which includes two motors coupled with differential ball screws in speed-summing arrangement, is experimentally validated with reference to the different operation modes of the
system (i.e. with active/active or active/stand-by motors). The validated model is then used to design the health-monitoring algorithms, with a special focus on the characterisation of the failure transient related to the detection, the isolation and the compensation of jamming faults, which imply a control laws switching to engage the appropriate operation mode
Motor speed reconstruction in a compact EMA for primary flight controls via sensor-fusion technique
No full textThe paper deals with the development and the performance characterisation of a sensor-fusion technique aiming to the reconstruction of the motor speed feedback in a compact EMA for primary flight control applications. The technique is based on the combination of the measurements of a LVDT and the Hall-effect sensors of the BLDC motor of the actuator. Firstly, the nonlinear dynamic model of the EMA used for the performance analysis is presented, successively the speed reconstruction technique is described, explaining the rationale underlying the design concept. The performances of the speed reconstruction are finally characterised in both frequency and time domains, by evaluating the errors of the speed estimates in both open-loop mode (directly imposing speed inputs) and closed-loop mode (simulating the position tracking response of the EMA)
- …
