Are objective measures of tricuspid annular motion and velocity used as frequently as recommended by current guidelines? A pilot study

In this retrospective study 420 echocardiograms from a single center were reviewed showing that TAPSE was acquired in 66% while TA TDI s’ signals were recorded in 98% of all echocardiograms. Based on these results greater efforts are required to standardize acquisition and reporting of objective measurements of RV function. Keywords: Echocardiography, Right ventricular dysfunction, TAPSE, Tricuspid annulus, M-mode, Tissue doppler imagin

Is mitral annular ascent useful in studying left ventricular function through left atrio-ventricular interactions?

Background: The mitral annulus (MA) is a crucial structure that is in constant motion throughout the cardiac cycle. The main purpose of this study was to determine if M-mode evaluation of the longitudinal motion of the MA could be useful to examine atrio-ventricular interactions. Methods: Echocardiographic data obtained from 150 patients (mean age 56 ± 16; 82 males) from the University of Cincinnati College of Medicine was evaluated to examine if any relationship exists between MA motion and measures of atrio-ventricular interactions. Results: Even though left atrial size, left ventricular (LV) mass index, LV ejection fraction (LVEF) and degree of LV diastolic dysfunction (LVDD) were significant echocardiographic variables affecting MA motion; LVEF and the degree of LVDD were the main determinants of MA excursion during systole (MAPSE) and after atrial contraction (MAa). Our results confirm the surrogate value of MAPSE with regards to LVEF and also show that the extent of MA excursion during systole is the main determinant of MAa. The effect of LV diastolic function applies more strongly to MAPSE than to MAa. However, the maximal MAa amplitude varies in accordance to the type of LVDD. Conclusions: We have shown for the first time that M-mode interrogation of the MA longitudinal motion appears useful to assess atrio-ventricular interactions. Since LV systolic and diastolic functions are so closely related; additional studies are now required to examine how this longitudinal measure correlates with known circumferential rotational data obtained with other imaging modalities. Keywords: Atrio-ventricular interaction, Echocardiography, Left atria, Left ventricle, Mitral annulus, M-mod

Structure and conformational dynamics of the domain 5 RNA hairpin of a bacterial group II Intron revealed by solution NMR and molecular dynamics simulations

Nuclear magnetic resonance (NMR) nuclear Overhauser enhancement (NOE) data obtained for a 35-nucleotide RNA segment of a bacterial group II intron indicate a helical hairpin structure in which three parts, a terminal pentaloop, a bulge, and a G-A mismatch, display no Watson–Crick base pairing. The 668 NOE upper distance bounds for atom pairs are insufficient to uniquely determine the conformation of these segments. Therefore, molecular dynamics simulations including time-averaged distance restraints have been used to obtain a conformational ensemble compatible with the observed NMR data. The ensemble shows alternating hydrogen bonding patterns for the mentioned segments. In particular, in the pentaloop and in the bulge, the hydrogen bonding networks correspond to distinct conformational clusters that could not be captured by using conventional single-structure refinement techniques. This implies that, to obtain a realistic picture of the conformational ensemble of such flexible biomolecules, it is necessary to properly account for the conformational variability in the structure refinement of RNA fragments