Abstract. X-ray fluoroscopically guided cardiac electrophysiological procedures are routinely carried out for diagnosis and treatment of cardiac arrhythmias. X-ray images have poor soft tissue contrast and, for this reason, overlay of static 3D roadmaps derived from pre-procedural volumetric data can be used to add anatomical information. However, the registration between the 3D roadmap and the 2D X-ray data can be compromised by patient respiratory motion. We propose a novel method to correct for respiratory motion using real-time image-based coronary sinus (CS) catheter tracking. The first step of the proposed technique is to use a blob detection method to detect all possible catheter electrodes in the Xray data. We then compute a cost function to select one CS catheter from all catheter-like objects. For correcting respiratory motion, we apply a low pass filter to the 2D motion of the CS catheter and update the 3D roadmap using this filtered motion. We tested our CS catheter tracking method on 1048 fluoroscopy frames from 15 patients and achieved a success rate of 99.3% and an average 2D tracking error of 0.4 mm ± 0.2 mm. We also validated our respiratory motion correction strategy by computing the 2D target registration error (TRE) at the pulmonary veins and achieved a TRE of 1.6 mm ± 0.9 mm.
A previous study of self-rated psychosocial aspects in patients with acute porphyria found that depression, and particularly anxiety, is more common in porphyria patients than in the general population or general medical outpatient attenders. Nearly half of the sample (46%) reported at least some problem with anxiety and/or depression: anxiety caseness was 26% and depression caseness was 13%. This paper extends our previous observations and investigates further the associations between porphyria and anxiety, depression and general mental health in 90 patients (58 acute intermittent porphyria, 32 variegate porphyria). The findings of this study confirm that anxiety is raised in patients with acute intermittent porphyria and with variegate porphyria, in both males and females, compared to the normative population and, using a series of questionnaires exploring the physical and psychosocial features of anxiety, that this anxiety is experienced as a 'relatively stable personality trait', rather than a 'transitory emotional state' (i.e. intrinsic rather than secondary to the porphyria).
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