Background: Atrial fibrillation (AF) presents a potential challenge when performing coronary computed tomography angiography (CTA). To date, there is no ideal protocol for CTA in patients with AF.We sought to design a protocol for single-heartbeat coronary CTA in patients with AF. Methods:We enrolled 32 patients with AF and a very low probability of coronary artery disease who were referred for CTA to assess pulmonary vein anatomy for catheter ablation. A 256-slice scanner was used. Twelve patients underwent CTA using non-gated triple Flash (NGTF) consisting of three prospective electrocardiogram (ECG)-triggered helical scans with a built-in ECG simulator, while retrospectively gated helical (RGH) was used in 20 patients. Radiation dose, and a 4-point scale was used to assess coronary artery image quality between CTA scan modes. Results: A total of 96 vessels were analyzed. The 4-point score showed no significant differences between the RGH and NGTF scans (2.9  0.6 vs. 2.8  0.8, respectively; p = 0.34). The number of coronary arteries with extensive blurring did not significantly differ between the protocols, and included four vessels (6.6%) in RGH vs. three vessels (8.3%) in NGTF (p = 0.5). Radiation exposure was significantly higher with RGH scans, with a dose-length product of 835  146mGy compared with 382  35 mGy for NGTF (p < 0.0001). Conclusions: Single heartbeat NGTF CTA has comparable image quality and significantly lower radiation dose compared to RGH scans in patients with AF. Whether this protocol can be used in next-generation computed tomography scanners has yet to be determined.