Catheter ablation is an established treatment option for patients with symptomatic atrial fibrillation (AF).1-3 Pulmonary vein (PV) angiography has been the initial imaging tool in AF ablation and is still used by up to 50 % of leading electrophysiologists.3 PV angiography still plays a major role in balloon-based ablation techniques routinely performed without electroanatomical mapping (EAM). Some very experienced centres do not feel any need for three-dimensional (3D) imaging due to their ability to orientate in two-dimensional (2D) fluoroscopic views.3D imaging is likely to better reflect relations between anatomic structures and ensures that all PVs are clearly identified. Therefore, it is not surprising that the majority of studies done on image integration of 3D shells into EAM show positive effects on radiation exposure, procedural and long-term success. [4][5][6] In particular, results of large multicentre registries clearly show the benefit of image integration regarding freedom from AF 7 in comparison with fluoroscopy-guided ablation. Integration of 3D reconstructions of pre-procedurally acquired data sets derived from multislice computed tomography (MSCT) or magnetic resonance imaging (MRI) into EAM systems has been introduced to guide left atrial (LA) ablation procedures. [8][9][10][11][12][13] However, these remote imaging technologies may not perfectly reflect the status found during ablation due to changes in cardiac rhythm and preload, and their impact on the LA volume for example. Therefore, the search for an intra-procedural technology close to realtime imaging continued and led to the development of rotational angiography.
Principles of Rotational AngiographyDifferent protocols of this technique have been introduced over time [14][15][16][17][18][19] having in common the principle of a C-arm run around the patients` region of interest (in case of AF ablation the LA) with acquisition of X-ray images with a certain rate of frames per second using a flat panel detector (see Figure 1). To enhance cardiac structures, contrast media is administered into the right atrium or the pulmonary artery and C-arm run is started after a delay reflecting the pulmonary transition time. Individual pulmonary transition time can be estimated by a bolus injection of contrast media into the pulmonary artery. This compensates for delayed enhancements due to low cardiac output. Alternatively, direct injection into the LA is performed and the C-arm run is started with a short delay. A more intense contrast of the LA may be seen after direct injection. However, contrast injection into the LA may lead to an artificial enlargement of its image. For enhancement of the oesophagus the patient is asked to swallow contrast paste. All these approaches provide data sets that allow for measurements in virtually unlimited planes and 3D reconstruction of the LA, PV, aorta and the oesophagus applying software on different specialised computer systems (e.g. Syngo X-Workplace, Siemens, Forchheim, Germany and EP Navigator, Philips, Best...