Right Atrial Scar Detection after Catheter Ablation: Comparison of 2D and High Spatial Resolution 3D-late Enhancement Magnetic Resonance Imaging

Rationale and Objectives: To prospectively compare the diagnostic performance of two-dimensional (2D) and high spatial resolution three-dimensional (3D) late enhancement magnetic resonance imaging (MRI) for the detection of scar tissue caused by catheter ablation of the right atrium in patients with atrial flutter. Materials and Methods: Forty-seven patients were enrolled. In 16 patients, imaging of the cavotricuspid isthmus was performed before and after catheter ablation, 16 subjects were imaged before, and 15 after catheter ablation, resulting in a total of 63 examinations. MRI included a standard 2D breathhold and a high-resolution navigator-gated 3D T1-weighted gradient-echo inversion-recovery sequence in right and left anterior oblique views. Two readers assessed the subjective image quality on a 4-point scale (1 = excellent) and the presence of late enhancement (blinded/ in consensus). Results: The average image quality was 1.6 for both imaging approaches. In consensus reading, the sensitivity was 83% versus 100%, specificity 97% versus 89%, accuracy 90% versus 94%, positive predictive value 96% versus 89%, negative predictive value 86% versus 100% for 20 and 3D, respectively. The interobserver agreement was 0.86 for 2D and 0.78 for 3D imaging. Conclusions: For the noninvasive identification of scars in the cavotricuspid isthmus after right atrial flutter, ablation 2D imaging was more consistent, whereas 3D sequences showed superior sensitivity for the depiction of late enhancement

Non-invasive Evaluation of Soft-Plaque-Restenosis in Coronary Artery Stents: Initial In-vitro Comparison of a Spectral Photon Counting CT and a Spectral Dual Layer CT System

International audienc

Secretory sphingomyelinase is upregulated in chronic heart failure: a second messenger system of immune activation relates to body composition, muscular functional capacity, and peripheral blood flow.

Sphingomyelinases (SMase) are key regulating enzymes of the intracellular and paracrine ceramide second messenger system that mediates immune response to inflammatory cytokines and oxidative stress. Vascular endothelial cells are a rich and regulatable source of secretory SMase (S-SMase). Chronic heart failure (CHF) is a state of endothelial dysfunction and latent immune activation. The significance of S-SMase has not been studied in CHF in detail. The aim of the present study is to characterize S-SMase activity in patients with CHF in relation to disease severity and to pathophysiological characteristics such as immune activation, vasodilator capacity, and skeletal muscle function and body composition. METHODS AND RESULTS:S-SMase activity was assessed by a fluorimetric method in 112 patients with CHF (age, 63 +/- 11 years; NYHA class I/II/III/IV, 9/48/46/9; LVEF, 30 +/- 15%; peak VO(2), 18.6 +/- 6.7 mL/kg/min) and in two control groups (healthy, n = 13 and hypertensive controls, n = 11). S-SMase activity was similar in both control groups (healthy, 150 +/- 121 pmol/mL h; hypertensive, 157 +/- 134 pmol/mL h) but was increased by >90% in CHF patients (299 +/- 283 pmol/mL h; P = 0.004). S-SMase elevation was not different between ischaemic and non-ischaemic CHF and increased stepwise with NYHA class (I, 206 +/- 202; II, 284 +/- 242; III, 306 +/- 212; IV, 440 +/- 665 pmol/mL h; P = 0.003). S-SMase correlated with peak VO(2) (R = -0.33, P = 0.0007) and with cytokine activation [tumour necrosis factor-alpha (TNF-alpha) R = 0.22, P = 0.02; sTNF-R1 R = 0.39, P < 0.0001]. S-SMase further correlated with reduced skeletal (quadriceps) muscle strength (R = -0.46, P < 0.0001) as well as impaired peripheral vasodilator capacity (R = -0.34, P = 0.02). In detailed body composition analysis (DEXA scan), S-SMase activity was highest in patients with cardiac cachexia (405 +/- 357 vs. non-cachectic patients: 233 +/- 202 pmol/mL h; P = 0.0007) and related to reduced lean tissue parameters but not to fat tissue parameters. In Cox proportional hazard analysis, elevated SMase related to impaired survival, independent of age, NYHA class, and mean BP (hazard ratio 2.92; 95% confidence interval 1.035-8.24; P = 0.04). CONCLUSION: S-SMase is upregulated in CHF, independent of aetiology. The association of S-SMase with clinical status, tissue amount, functional capacity of skeletal muscle tissue, and vasodilator capacity suggests that S-SMase-mediated signalling may contribute to regulatory processes of CHF pathophysiology

Hydrodynamic and Longitudinal Impedance Analysis of Cerebrospinal Fluid Dynamics at the Craniovertebral Junction in Type I Chiari Malformation

Elevated or reduced velocity of cerebrospinal fluid (CSF) at the craniovertebral junction (CVJ) has been associated with type I Chiari malformation (CMI). Thus, quantification of hydrodynamic parameters that describe the CSF dynamics could help assess disease severity and surgical outcome. In this study, we describe the methodology to quantify CSF hydrodynamic parameters near the CVJ and upper cervical spine utilizing subject-specific computational fluid dynamics (CFD) simulations based on in vivo MRI measurements of flow and geometry. Hydrodynamic parameters were computed for a healthy subject and two CMI patients both pre- and post-decompression surgery to determine the differences between cases. For the first time, we present the methods to quantify longitudinal impedance (LI) to CSF motion, a subject-specific hydrodynamic parameter that may have value to help quantify the CSF flow blockage severity in CMI. In addition, the following hydrodynamic parameters were quantified for each case: maximum velocity in systole and diastole, Reynolds and Womersley number, and peak pressure drop during the CSF cardiac flow cycle. The following geometric parameters were quantified: cross-sectional area and hydraulic diameter of the spinal subarachnoid space (SAS). The mean values of the geometric parameters increased post-surgically for the CMI models, but remained smaller than the healthy volunteer. All hydrodynamic parameters, except pressure drop, decreased post-surgically for the CMI patients, but remained greater than in the healthy case. Peak pressure drop alterations were mixed. To our knowledge this study represents the first subject-specific CFD simulation of CMI decompression surgery and quantification of LI in the CSF space. Further study in a larger patient and control group is needed to determine if the presented geometric and/or hydrodynamic parameters are helpful for surgical planning