Modern tests of Lorentz invariance

Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible. The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.Comment: Modified and expanded discussions of various points. Numerous references added. Version matches that accepted by Living Reviews in Relativit

Dobutamine 3D strain in the left anterior descending subtended ventricular territory: evidence for relationship with the respective velocity flow reserve

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Three dimensional speckle tracking imaging (3DST), provides an evolving means to interrogate left ventricular (LV) function. However, its clinical application still remains limited. Purpose Purpose of the study was to interrogate the relationship between regional deformation by 3DST in left anterior descending artery (LAD) subtended territory and the respective coronary flow reserve (CFR). Methods Fifty patients aged 63 ± 6 years with chronic coronary syndromes were studied. Patients had no evidence of dobutamine (DOB) induced ischemia in LAD territory. Distal LAD CFR was estimated by adenosine Doppler echo (140mg/kg/min). 3DST derived integral strain (IS) and respective components (longitudinal -LS, circumferential –CS, radial -RS) were estimated by a full volume sweep (3.5 MHz sector probe) at &amp;gt;20 volumes/sec. A 16 LV sectors (sc) polar map was provided (Artida,Toshiba) with 10/16 sectors (sc) analysed, 6 sc being the conventional LAD territory (sc: 3,4,5,6,7,8) and another 4 sc being adjacent ones (sc: 1, 2, 9, 10). 3D datasets acquired at rest (R) and low dose DOB (20mg/kg/min). LV mass was automatically measured from volumetric data sets and its variability during cardiac cycle was considered as an index of coherence for true LV borders recognition. Results CFR was &amp;gt;2 in all pts (range 2.0-4.2, 2.74 + 0.46). Mean variability of LV mass between R and DOB was 0.044 (range: -0.090-0.008, p = ns). 3DST strain was related with LAD CFR as follows: 1.For IS: at R: sc1: r = 0.38, p = 0.023, sc3: r = 0.44, p = 0.006, sc5: r = 0.35, p = 0.03, sc9: r = 0.50, p = 0.002. At DOB sc7: r = 0.31, p = 0.05. 2.For LS: at R: sc5: r=-0.40, p = 0.01. 3.For CS: at R: sc5: r=-0.33, p = 0.02, sc5: r=-0.46, p = 0.004. 4.For RS: at R: sc9: r=-0.38, p = 0.08. The % changes of regional IS post DOB compared to R were also related with CFR LAD in the sectors sc1 and sc3 (r = 0.34, p = 0.05, and p = 0.40, p = 0.002 respectively). Conclusion 3DST derived LV deformation indices in the LAD territory are related with the respective CFR. LV regional integral strain has a stronger relationship with LAD CFR when compared to the partial vectors. The 3DST derived deformation indices seem sensitive enough to reproduce the flow function relationship in the LAD territory. Thus, potential applicability has to be supported. </jats:sec

Transcatheter tricuspid valve-in-valve: evolution of tricuspid hydraulic performance and respective changes of right ventricular anatomy and function

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Transcatheter tricuspid valve-in-valve replacement (TVIV) is an emerging therapy for dysfunctional surgically implanted bioprostheses. There are few data about the evaluation of hydraulic performance of these valves. Purpose Purpose of this single-center study was to evaluate the evolution of the right ventricular anatomy and function and the respective changes of TVIV hydraulics. Methods Six patients who underwent Sapien S3 TVIV (size 29mm) were studied (age 57 ± 11years, 3/6 in sinus rhythm, all in NYHA class III/IV). Inspiratory (insp) and expiratory (exp) TV mean gradients (mGR) , respective heart rate (HR), right ventricular end-diastolic diameter (RVEDd mm), RV fractional area change (FAC%) and RV free wall longitudinal strain (RV strain) were estimated at baseline (B), 1 month (1m) and later than 6 months (&amp;gt;6m). Results NYHA class fell by at least 1 scale at 1m and remained either stable or further improved at 6m. RVEDd increased early at 1m (B: 33.5 ± 5.3mm vs 1m: 41.3 ± 3.3mm, p = 0.018) and remained unchanged at &amp;gt;6m (&amp;gt;6m: 41 ± 4.2mm vs 1m: 41.3 ± 3.3mm, p = ns). FAC improved late at 6m (B: 42.6 ± 2.8% vs 6m: 56 ± 6.2% p = 0.04). RV strain remained unchanged (B: -17 ± 5.5% vs 1m: 16 ± 7% vs &amp;gt;6m: -20 ± 6%, p = ns). The improvement in both mGR-exp and mGR-insp was evident at 1m and remained unchanged afterwards: (mGR-exp: B 9 ± 4mmHg, 1m: 3 ± 2, &amp;gt;6m: 5 ± 1, both p &amp;lt; 0.05 vs B, mGR-insp: B 15 ± 5mmHg, 1m: 6 ± 2, &amp;gt;6m: 8 ± 2, both p &amp;lt; 0.05 vs B). The respective heart rates during measurements at inspiration and expiration were similar (HR-exp: B 72 ± 22bpm, 1m: 81 ± 22bpm, &amp;gt;6m: 65 ± 9bpm, HR-insp: B 75 ± 27bpm, 1m: 79 ± 18bpm, &amp;gt;6m: 69 ± 3bpm) Absolute values for both mGR-insp and mGR-exp, despite progressive improvement, showed variations exceeding the conventional cut-off for TV prosthetic valve dysfunction of 6 mmHg, despite preserved clinical improvement. Variations of mGR were not related with the respective HR. Conclusion Following TVIV, early clinical improvement was related with a concomitant increase in RV volume, whereas RV functional indices showed a delayed response. Conventional echocardiographic hydraulics showed variability, often exceeding threshold for definition of prosthetic valve dysfunction. Thus, the significance of TV gradient after TVIV should be interpreted in the clinical context, taking into account respiratory changes. </jats:sec