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(1) Background: Computer tomography (CT) is an imaging modality used in the pre-planning of radiofrequency catheter ablation (RFA) procedure in patients with cardiac arrhythmias. However, it is associated with a considerable ionizing radiation dose for patients. This study aims to develop and validate low-dose CT scanning protocols of the left atrium (LA) for RFA guidance. (2) Methods: 68 patients scheduled for RFA of atrial fibrillation were sequentially assigned to four groups of ECG-gated scanning protocols, based on the set tube current (TC): Group A (n = 20, TC = 33 mAs), Group B (n = 18, TC = 67 mAs), Group C (n = 10, TC = 135 mAs), and control Group D (n = 20, TC = 600 mAs). We used a 256-row multidetector CT with body weight-dependent tube voltage of 80 kVp (<70 kg), 100 kVp (70–90 kg), and 120 kVp (>90 kg). We evaluated scanning parameters including radiation dose, total scanning procedure time and signal-to-noise ratio (SNR). (3) Results: The average effective radiation dose (ED) was lower in Group A in comparison to Group B, C and D (0.83 (0.76–1.10), 1.55 (1.36–1.67), 2.91 (2.32–2.96) and 9.35 (8.00–10.04) mSv, p < 0.05). The total amount of contrast media was not significantly different between groups. The mean SNR was 6.5 (5.8–7.3), 7.1 (5.7–8.2), 10.8 (10.1–11.3), and 12.2 (9.9–15.7) for Group A, B, C and D, respectively. The comparisons of SNR in group A vs. B and C vs. D were without significant differences. (4) Conclusions: Optimized pre-ablation CT scanning protocols of the LA can reduce an average ED by 88.7%. Three dimensional (3D) models created with the lowest radiation protocol are useful for the integration of electro-anatomic-guided RFA procedures. [ABSTRACT FROM AUTHOR]

Background. Catheter ablation in the left atrium has become a common therapeutic strategy in the management of atrial fibrillation (AF). The high degree of success and safety profile of this procedure is dependent on precise knowledge of the true anatomy in the chamber. This information is imported mostly from cardiac computed tomography. A novel method for imaging the left atrial anatomy is three-dimensional rotational angiography (3DRA). Methods. The aim of our study was to the compare clinical outcome and safety of catheter ablation for atrial fibrillation guided by 3DRA vs. conventional CT scan. One hundred and twenty-five patients referred for AF catheter ablation at St. Anne's University Hospital Brno were included in the retrospective analysis of clinical outcome within the first year after the procedure. Results. There was a close correlation in overall procedural parameters between the groups. The frequency of recurrent episodes of AF (24% in CT-guided group vs. 27% in 3DRA-guided group, P=0.721) as well as the onset of atypical atrial flutter after the procedure (10% vs. 8%, respectively, P=0.731) were similar in both groups. No difference in the number of patients necessitating repeat ablation (5% vs. 5%, P=0.984) was found. Procedural complications of ablations guided by 3DRA were comparable with those guided by CT (2% vs. 3%, respectively, P=0.568). Conclusion. 3DRA has proven to be a safe and simple method for imaging the left atrium and guiding catheter ablation for AF. This approach is anticipated to become a new standard in 3D reconstruction of the left atrium. [ABSTRACT FROM AUTHOR]