Left atrium and pulmonary vein imaging using sub-millisiviert cardiac computed tomography: Impact on radiofrequency catheter ablation cumulative radiation exposure and outcome in atrial fibrillation patients

Background The outcome of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) has improved thanks to left atrium (LA) anatomy reconstruction by cardiac computed tomography (CCT). A new model-based iterative reconstruction algorithm (MBIR) provides image noise reduction achieving effective radiation dose (ED) close to chest X-ray exposure. Aim of this study was comparing RFCA procedural characteristics, AF recurrence and radiation exposure between patients in whom RFCA was guided by CCT image integration with MBIR versus a CCT standard protocol. Methods Three-hundred consecutive patients with drug-refractory AF were studied with CCT using MBIR (Group 1; N:150) or CCT with standard protocol (Group 2; N:150) for LA evaluation and 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 radiation exposure were compared. Results Group 1 showed higher SNR (25.9 ± 7.1 vs. 16.2 ± 4.8, p < 0.001) and CNR (23.3 ± 7.1 vs. 12.2 ± 4.2, p < 0.001) and lower image noise (22.3 ± 5.2 vs. 32.6 ± 8.1 HU, p < 0.001), fluoroscopy time (21 ± 12 vs. 29 ± 15 min, p < 0.01) and procedural duration (135 ± 89 vs. 172 ± 55, p < 0.001). Group 1 showed a 94% reduction of ED as compared to Group 2 (CCT-ED related: 0.41 ± 0.04 vs. 6.17 ± 4.11 mSv, p < 0.001; cumulative CCT + RFCA-ED related: 21.9 ± 17.9 vs. 36.0 ± 24.1 mSv, p < 0.001) with similar rate of AF recurrence (25% vs. 29%, p = 0.437). Conclusions CCT with MBIR allows accurate reconstruction of LA anatomy in AF patients undergoing RFCA with a sub-millisievert ED and comparable success rate of RFCA as compared to a standard CCT scan protocol.