P933Zero or near-zero x-ray ablation procedures for supraventricular tachycardias using two different three-dimensional mapping systems: comparison of radiation exposure times

AbstractAt present, three-dimensional mapping is often used during cardiac ablations with an explicit goal of decreasing radiation exposure; three-dimensional mapping was introduced in our institution in 2007, but not specifically to decrease fluoroscopy time. We document fluoroscopy use and catheterisation times in this setting. Data were obtained retrospectively from patients who underwent ablation for atrioventricular nodal re-entrant tachycardia from January, 2004 to December, 2011. A total of 93 patients were included in the study. Among them, 18 patients who underwent radiofrequency ablation without three-dimensional mapping were included in Group 1, 13 patients who underwent cryoablation without three-dimensional mapping were included in Group 2, and 62 patients who underwent cryoablation with three-dimensional mapping were included in Group 3. Mean fluoroscopy times differed significantly (34.3, 23.4, and 20.3 minutes, p<0.001) when all the groups were compared. Group 3 had a shorter average fluoroscopy time that did not reach significance when compared directly with Group 2 (p=0.29). An unadjusted linear regression model showed a progressive decrease in fluoroscopy time (p=0.002). Mean total catheterisation times differed significantly (180, 211, and 210 minutes, p=0.02) and were related to increased ablation times inherent to cryoablation techniques. Acute success was achieved in 89, 100, and 97% of patients (p=0.25), and chronic success was achieved in 80, 92, and 93% of patients (p=0.38). Complication rates were similar (17, 23, and 7%, p=0.14). In conclusion, three-dimensional mapping systems decrease fluoroscopy times even without an explicit goal of zero fluoroscopy. Efficacy and safety of the procedure have not changed.

Download Full-text

High-resolution three-dimensional mapping of individual grains in polycrystals by topotomography

Journal of Applied Crystallography ◽

10.1107/s002188980703035x ◽

2007 ◽

Vol 40 (5) ◽

pp. 905-911 ◽

Cited By ~ 25

Author(s):

Wolfgang Ludwig ◽

Erik Mejdal Lauridsen ◽

Soeren Schmidt ◽

Henning Friis Poulsen ◽

José Baruchel

Keyword(s):

Grain Shape ◽

Three Dimensional ◽

Projection Data ◽

Second Phase ◽

Additional Contribution ◽

Beam Position ◽

Transmitted Beam ◽

X Ray ◽

Three Dimensional Mapping ◽

Dimensional Mapping

By orienting a crystal grain with its diffraction vector along the sample rotation axis, it is possible to use powerful tomographic and topographic imaging techniques to reconstruct the three-dimensional grain shape inside a polycrystalline sample. The acquisition and reconstruction can be performed from projection images with the detector positioned either in the diffracted-beam or in the direct-beam position. In the first case, the projection data consist of a series of integrated, monochromatic beam X-ray diffraction topographs of the grain under investigation. In the second case, the corresponding diffraction contrast in the transmitted beam may be interpreted as an additional contribution to the X-ray attenuation coefficient of the material. This latter variant is restricted to grains with small orientation spread but offers the possibility to characterize simultaneously the three-dimensional grain shape and the absorption microstructure of the surrounding sample material. The contrast mechanism is sensitive to local strain fields and can, in certain cases, reveal details of the grain microstructure, such as the presence of second-phase inclusions. The methodology is successfully demonstrated on an aluminium polycrystal, with a resulting three-dimensional mapping accuracy better than 7 µm. The possibilities and limitations of the technique are listed and its performance relative to other three-dimensional mapping techniques is discussed.

Download Full-text