Validation of Noninvasive Measurements of Cardiac Output in Mice Using Echocardiography

Although multiple echocardiographic methods exist to calculate cardiac output (CO), they have not been validated in mice using a reference method. Echocardiographic and flow probe measurements of CO were obtained in mice before and after albumin infusion and inferior vena cava occlusions. Echocardiography was also performed before and after endotoxin injection. Cardiac output was calculated using LV volumes obtained from a M Mode or a 2D view, LV stroke volume calculated using the pulmonary flow, or estimated using pulmonary VTI. Close correlations were demonstrated between flow probe-measured CO and all echocardiographic measurements of CO. All echocardiographic-derived CO overestimated the flow-probe measured CO. 2D images-derived CO was associated with the smallest overestimation of CO. Interobserver variability was lowest for pulmonary VTI derived CO. In mice, CO calculated from 2D parasternal long axis images is most accurate when compared to flow probe measurements, however, pulmonary VTI-derived CO is subject to less variability

Méthode d'évaluation de l'asynchronisme mécanique chez les insuffisants cardiaques systoliques par l'étude du rocking ventriculaire en IRM

L'asynchronisme mécanique produit un mouvement caractéristique de rocking du ventricule gauche (VG) autour de son petit axe mais dont la mesure objective reste difficile. Objectifs: 1) développer une nouvelle méthode de mesure de ce rocking à partir d'une IRM cardiaque 2) étudier ce paramètre chez des insuffisants cardiaques (le) et 3) évaluer l'impact du rocking sur l'évolution de l'IC. Méthodes: La mesure du rocking a été mise au point à partir d'images d'IRM taggées 4-cavités puis rétrospectivement étudiée sur une population d'IC. Les résultats ont été confrontés aux caractéristiques des patients ainsi qu'à l'évolution de leur cardiopathie. Résultats: Les IRMs de 54 patients ont été analysées rétrospectivement. Le rocking moyen du VG était de 2,6+-1,6 et positivement corrélé avec l'asynchronisme électrique et le sexe féminin (P<O,05) mais pas avec la fibrose myocardique ou la fonction ventriculaire droite. L'absence de rocking était associée à 3-6 mois à une meilleure augmentation de FEVG. Conclusions: Le rocking ventriculaire est mesurable en IRM cardiaque et pourrait impacter l'évolution d'une cardiopathie.PARIS13-BU Serge Lebovici (930082101) / SudocSudocFranceF

Impact cardio-vasculaire de l entraînement au marathon chez des sportifs amateurs

PARIS7-Xavier Bichat (751182101) / SudocSudocFranceF

Evaluation en échocardiographie d'effort de l'asynchronisme cardiaque dans les cardiomyopathies dilatées hypokinétiques

PARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Comment évaluer et traiter l'insuffisance cardiaque à fraction d'éjection préservée

L'insuffisance cardiaque à fraction d'éjection préservée est une définition qui remplace l'insuffisance cardiaque diastolique. Elle est aujourd'hui la forme la plus fréquente des formes d'insuffisance cardiaque du fait du vieillissement de la population. Son pronostic semble être proche de celui de l'insuffisance cardiaque à fonction systolique altérée. Le diagnostic s'aide de l'écho doppler cardiaque et du dosage du peptide natriurétique de type B. À ce jour, aucun traitement n'a fait la preuve de son efficacité mais les essais thérapeutiques ont été rares à ce jour. Les bloqueurs du système rénine-angiotensine, qui apparaissaient prometteurs, n'ont pas démontré leur efficacité. Cette revue reprend les aspects épidémiologiques, diagnostiques, physiopathologiques et thérapeutiques de cette affection

A Dual Tissue-Doppler Optical-Flow Method for Speckle Tracking Echocardiography at High Frame Rate

International audienc

Coupling myocardium and vortex dynamics in diverging-wave echocardiography

International audienc

High-Frame-Rate Echocardiography Using Coherent Compounding With Doppler-Based Motion-Compensation

International audience—High-frame-rate ultrasonography based on coherent compounding of unfocused beams can potentially transform the assessment of cardiac function. As it requires successive waves to be combined coherently, this approach is sensitive to high-velocity tissue motion. We investigated coherent compounding of tilted diverging waves, emitted from a 2.5 MHz clinical phased array transducer. To cope with high myocardial velocities, a triangle transmit sequence of diverging waves is proposed, combined with tissue Doppler imaging to perform motion compensation (MoCo). The compound sequence with integrated MoCo was adjusted from simulations and was tested in vitro and in vivo. Realistic myocardial velocities were analyzed in an in vitro spinning disk with anechoic cysts. While a 8 dB decrease (no motion versus high motion) was observed without MoCo, the contrast-to-noise ratio of the cysts was preserved with the MoCo approach. With this method, we could provide high-quality in vivo B-mode cardiac images with tissue Doppler at 250 frames per second. Although the septum and the anterior mitral leaflet were poorly apparent without MoCo, they became well perceptible and well contrasted with MoCo. The septal and lateral mitral annulus velocities determined by tissue Doppler were concordant with those measured by pulsed-wave Doppler with a clinical scanner. To conclude, high-contrast echo-Manuscrip

Remote Ischemic Preconditioning Does Not Improve the Six Minutes Walk Test Performance in Chronic Heart Failure Patients: a Randomised Pilot Trial

International Journal of Exercise Science 14(2): 1354-1362, 2021. Cycles of ischemia and reperfusion induced with a pressure cuff on a skeletal muscle, also know as remote ischemic preconditioning (RIPC), appears to improve performance in different time-trial events in healthy individuals. Our primary goal was to assess the effect of RIPC in heart failure (HF) patients’ functional capacity using the six-minute walk test (6MWT). A randomized crossover design comparing RIPC (4 x five-minutes of upper arm ischemia) to the SHAM procedure was done in 15 patients prior to a 6MWT. The primary outcome measure was the total distance walked in a standardized 6MWT (20m corridor). Metabolic and hemodynamic responses were measured using gas exchange analysis with a portable metabolic analyzer and peripheral skeletal muscle oxygen saturation (smO2) with near-infrared spectroscopy. The total distance travelled during 6MWT was not significantly different between the RIPC (347 ± 63 m) and the SHAM procedure (352 ± 65 m; p = 0.514). Relative oxygen uptake did not change when comparing interventions: 10.26 ± 2.01 ml/kg/min vs 10.69 ± 2.51 ml/kg/min (RIPC vs SHAM, respectively, p = 0.278). As well, no significant differences were observed for heart rate, respiratory exchange ratio, smO2, and ventilation. Even though HF patients tolerated well the RIPC intervention, it did not provide any significant improvement in functional capacity and other physiological parameters in our sample of patients