The study assessed whether end-diastolic wall thickness (EDWT), measured with echocardiography, is an important marker of myocardial viability in patients with suspected myocardial hibernation, and ...it compared this index to currently established diagnostic modalities of dobutamine stress echocardiography (DSE) and rest-redistribution thallium-201 (T1-201) scintigraphy.
Because myocardial necrosis is associated with myocardial thinning, preserved EDWT may provide a simple index of myocardial viability that is readily available from the resting echocardiogram.
Accordingly, 45 patients with stable coronary artery disease and ventricular dysfunction underwent rest 2D echocardiograms, DSE and rest-redistribution T1-201 tomography before revascularization and a repeat resting echocardiogram > or =2 months later.
Global wall motion score index decreased from 2.38 +/- 0.73 to 1.94 +/- 0.82 after revascularization (p < 0.001). Thirty-eight percent of severely dysfunctional segments recovered resting function. Compared to segments without recovery of resting function, those with recovery had greater EDWT (0.94 +/- 0.18 cm vs. 0.67 +/- 0.22 cm, p < or = 0.0001) and a higher T1-201 uptake (78 +/- 13% vs. 59 +/- 21%; p < 0.0001). An EDWT >0.6 cm had a sensitivity of 94% and specificity of 48% for recovery of function. Similarly, a T1-201 maximal uptake of > or =60% had a sensitivity of 91% and specificity of 50%. Receiver operating characteristic curves for prediction of recovery of regional and global function were similar for EDWT and maximum T1-201 uptake. Combination of EDWT and any contractile reserve during DSE for recovery of regional function improved the specificity to 77% without a significant loss in sensitivity (88%).
End-diastolic wall thickness is an important marker of myocardial viability in patients with suspected hibernation, and it can predict recovery of function similar to T1-201 scintigraphy. Importantly, a simple measurement of EDWT < or =0.6 cm virtually excludes the potential for recovery of function and is a valuable adjunct to DSE in the assessment of myocardial viability.
Abstract only
Introduction:
3D color Doppler allows a direct measurement of Vena Contracta (VC) area in patients with mitral regurgitation (MR), without the need for geometric assumptions.
...Hypothesis:
3D color Doppler VC area provides a more accurate assessment of MR severity than the conventional 2D color Doppler VC diameter.
Methods:
Patients with ≥ mild MR underwent 2D and 3D color Doppler and a quantitative echo-Doppler study. 2D VC diameter was measured from a zoomed parasternal long-axis view. 3D VC area was acquired using real-time 3D (Philips) and measured off-line (TomTec). MR severity was assessed both quantitatively, as effective regurgitant orifice area from pulsed Doppler EROA = (mitral stroke volume - aortic stroke volume)/MR time velocity integral, and semi-quantitatively as recommended by the American Society of Echocardiography.
Results:
61 patients (65 ± 15 years) were studied. MR severity was mild in 25%, moderate in 36%, and moderate to severe or severe in 39%. Mitral valve pathology was prolapse in 33%, restricted closure in 44% and annular calcification in 7%. Regurgitant MR jet was eccentric in 49% of patients. For all patients, 3D VC area correlated significantly with EROA, better than 2D VC diameter (figure
). The advantage of 3D VC area over 2D VC diameter was more pronounced in eccentric jets (r=0.76, p< 0.001 vs. r=0.5, p =0.006, respectively) and in moderate to severe or severe MR (r=0.65, p<0.001 vs. r =0.13, p=0.54, respectively).
Conclusions
: Measurement of VC area is feasible with real-time 3D and provides a simple parameter that accurately reflects MR severity, particularly in eccentric and clinically significant MR where geometric assumptions may be challenging.
Detection of vulnerable plaques NARULA, Jagat; WILLERSON, James T; ZOGHBI, William A
Journal of the American College of Cardiology,
2006, Volume:
47, Issue:
8
Journal Article
The mechanisms that drive disk winds are a window into the physical processes that underlie the disk. Stellar-mass black holes are an ideal setting in which to explore these mechanisms, in part ...because their outbursts span a broad range in mass accretion rate. We performed a spectral analysis of the disk wind found in six Chandra/HETG observations of the black hole candidate 4U~1630\(-\)472, covering a range of luminosities over two distinct spectral states. We modeled both wind absorption and extended wind re-emission components using PION, a self-consistent photoionized absorption model. In all but one case, two photoionization zones were required in order to obtain acceptable fits. Two independent constraints on launching radii, obtained via the ionization parameter formalism and the dynamical broadening of the re-emission, helped characterize the geometry of the wind. The innermost wind components (\(r \simeq {10}^{2-3}\) \(GM/{c}^{2}\)) tend towards small volume filling factors, high ionization, densities up to \(n \simeq {10}^{15-16} {\text{cm}}^{-3}\), and outflow velocities of \(\sim 0.003c\). These small launching radii and large densities require magnetic driving, as they are inconsistent with numerical and analytical treatments of thermally driven winds. Outer wind components (\(r \simeq {10}^{5}\) \(GM/{c}^{2}\)) are significantly less ionized and have filling factors near unity. Their larger launching radii, lower densities (\(n \simeq {10}^{12} {\text{cm}}^{-3}\)), and outflow velocities (\(\sim 0.0007c\)) are nominally consistent with thermally driven winds. The overall wind structure suggests that these components may also be part of a broader MHD outflow and perhaps better described as magneto-thermal hybrid winds.
The very small accretion disks in ultra-compact X-ray binaries (UCXBs) are special laboratories in which to study disk accretion and outflows. We report on three sets of new (250 ks total) and ...archival (50 ks) Chandra/HETG observations of the "dipping" neutron-star X-ray binary 4U 1916\(-\)053, which has an orbital period of \(P\simeq 50\)~minutes. We find that the bulk of the absorption in all three spectra originates in a disk atmosphere that is redshifted by \(v\simeq 220-290\) \(\text{km}\) \(\text{s}^{-1}\), corresponding to the gravitational redshift at radius of \(R \sim 1200\) \(GM/{c}^{2}\). This shift is present in the strongest, most highly ionized lines (Si XIV and Fe XXVI), with a significance of 5\(\sigma\). Absorption lines observed during dipping events (typically associated with the outermost disk) instead display no velocity shifts and serve as a local standard of rest, suggesting that the redshift is intrinsic to an inner disk atmosphere and not due to radial motion in the galaxy or a kick. In two spectra, there is also evidence of a more strongly redshifted component that would correspond to a disk atmosphere at \(R \sim 70\) \(GM/{c}^{2}\); this component is significant at the 3\(\sigma\) level. Finally, in one spectrum, we find evidence of disk wind with a blue shift of \(v = {-1700}^{+1700}_{-1200}\) \(\text{km}\) \(\text{s}^{-1}\). If real, this wind would require magnetic driving.
A multi-epoch X-ray spectral and variability analysis is conducted for the narrow-line Seyfert 1 (NLS1) active galactic nucleus (AGN) Mrk 478. All available X-ray data from XMM-Newton and Suzaku ...satellites, spanning from 2001 to 2017, are modelled with a variety of physical models including partial covering, soft-Comptonisation, and blurred reflection, to explain the observed spectral shape and variability over the 16 years. All models are a similar statistical fit to the data sets, though the analysis of the variability between data sets favours the blurred reflection model. In particular, the variability can be attributed to changes in flux of the primary coronal emission. Different reflection models fit the data equally well, but differ in interpretation. The use of reflionx predicts a low disc ionisation and power law dominated spectrum, while relxill predicts a highly ionised and blurred reflection dominated spectrum. A power law dominated spectrum might be more consistent with the normal X-ray-to-UV spectral shape (aox). Both blurred reflection models suggest a rapidly spinning black hole seen at a low inclination angle, and both require a sub-solar (~0.5) abundance of iron. All physical models require a narrow emission feature at 6.7 keV likely attributable to Fe xxv emission, while no evidence for a narrow 6.4 keV line from neutral iron is detected.
We present the results of X-ray spectral and timing analyses of the closest gamma-ray emitting narrow-line Seyfert 1 (\(\gamma\)-NLS1) galaxy, 1H 0323+342. We use observations from a recent, ...simultaneous XMM-Newton/NuSTAR campaign. As in radio-quiet NLS1s, the spectrum reveals a soft excess at low energies (\(\lesssim2\) keV) and reflection features such as a broad iron K emission line. We also find evidence of a hard excess at energies above \(\sim35\) keV that is likely a consequence of jet emission. Our analysis shows that relativistic reflection is statistically required, and using a combination of models that includes the reflection model relxill for the broadband spectrum, we find an inclination of \(i=63^{+7}_{-5}\) degrees, which is in tension with much lower values inferred by superluminal motion in radio observations. We also find a flat (\(q=2.2\pm0.3\)) emissivity profile, implying that there is more reflected flux than usual being emitted from the outer regions of the disk, which in turn suggests a deviation from the thin disk model assumption. We discuss possible reasons for this, such as reflection off of a thick accretion disk geometry.
PDF
