Moderated Posters session: complementary role of imaging techniques

Background: The outcome of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) has improved thanks to left atrium (LA) anatomy reconstruction by computed tomography with adaptive statistical iterative reconstruction algorithm (CT-ASIR) before the procedure. However, CT-ASIR strategy is associated to an increase of cumulative effective radiation dose (ED) in these patients. Recently, a model-based iterative reconstruction algorithm (MBIR, GE Healthcare, Waukesha,Wisconsin) has been developed (CT-MBIR) for image noise reduction reducing the ED close to chest X-ray exposure. The aim of this study is to compare the CT and RFCA characteristics, AF recurrence after procedure and radiation exposure between RFCA guided by image integration with CT-ASIR versus CT-MBIR Methods and Materials: One-hundred twenty consecutive patients with drug-refractory paroxysmal or persistent AF were addressed to CT-ASIR (Group 1; N: 60; mean age 60.3 ± 10.1 yo; male: 46) or CT-MBIR protocol (Group 2; N: 60; mean age 59.7 ± 11.3 yo; male:45) for evaluation of LA before RFCA. All patients were subsequently treated by image integration-supported RFCA. Image noise, signal to noise ratio (SNR), contrast to noise ratio (CNR), RFCA procedural characteristics, rate of AF recurrence and CT radiation exposure were measured and compared between the two groups. Results: The two groups were homogeneous in terms of demographic characteristics, cardiovascular risk factors, prevalence of persistent AF, medical therapy and echocardiographic characteristics. The mean follow-up was similar (578 ± 284 vs. 591 ± 278 days, respectively, p:ns). Group 2 showed a higher signal to noise ratio (25.9 ± 7.1 vs. 13.8 ± 5.1) and contrast to noise ratio (22.7 ± 6.5 vs. and 14.08 ± 4.1) of left atrium as compared to Group 1 (p<0.001). No differences were found in terms of RFCA parameter [procedural duration (130.9 ± 130.6. vs. 143.8 ± 80.4 min); fluoroscopy time (27.9 ± 14.1.0 vs. 32.0 ± 16.4 min); pulmonary veins isolated (3.8 ± 0.4 vs. 3.9 ± 0.4)] and the rate of AF recurrence (31% vs. 29%) between Group 2 vs Group 1. Group 2 showed a 94% reduction of ED as compared to Group 1 (0.4 ± 0.04 mSv vs 6.4 ± 1.8 mSv, p<0.01). Conclusions: CT-MBIR allows accurate non-invasive reconstruction of LA anatomy in AF patients undergoing to RFCA with a submillisievert effective radiation and comparable success rate of RFCA with CT-ASIR technique.