Abstract Introduction There are a variety of approaches for pre-procedural imaging to facilitate atrial fibrillation (AF) ablation. Intra-procedural three-dimensional rotational angiography (3DRA) is the least employed method and it can be advantageous regarding efficiency and procedural logistics (1). There is an open question whether LA imaging could improve safety and outcomes of cryoballoon (CB) ablation. Purpose The aim of this study is to evaluate possible benefits of 3DRA for procedural success, safety and long-term outcomes of CB ablation. Methods We designed a single-centre unblinded randomised clinical trial and recruited 134 patients (64.2% male, 59.0±11.6 years) with paroxysmal (93.3%) and early-persistent AF. Patients were randomised to no imaging or 3DRA which was performed intra-procedurally after trans-septal puncture. Angiographic images were segmented and overlaid to the fluoroscopy screen to guide the ablation procedure. Patients were scheduled for follow-up visits and twenty-four hour ECG recordings at 3, 6 and 12 months, and every 6 months thereafter. Results Of all the patients recruited, 66 (49.3%) were randomised to 3DRA and angiography was successfully performed in all but one patient (1.5%). Procedure time was significantly longer when 3DRA was performed (86.7±27.8 min compared to 67.2±22.1 in non-3DRA group, p<0.001). Total radiation dose (447.4±485.0 vs. 133.9±166.2 mGy, p<0.001) and contrast administration (131.8±28.3 vs. 40.8±26.5 ml, p<0.001) were significantly higher in the 3DRA group (Table 1). In patients who received no imaging one pulmonary vein (PV) couldn’t be isolated in 2 patients while this occurred in 3 patients in the 3DRA group (OR 1.57, 95% CI 0.25-9.72). Only minor complications were reported in both groups. Five patients developed large haematoma (4 in the 3DRA group vs. 1 in the control group). In each group there were 3 incidents of impending or transient phrenic nerve palsy. During 12 months of follow-up, 88.2% of patients in the control group and 81.8% in the 3DRA group were free of atrial fibrillation (OR 1.67, 95% CI 0.63-4.38). Two patients from the control group developed atrial flutter and were treated by ablation. In total, 10 patients underwent redo procedures (7 in the control and 3 in the 3DRA group respectively) and PV reconnections were detected in 9 cases. Conclusion 3DRA is a safe and efficient intra-procedural imaging method to guide CB ablation of AF. However, it significantly increases procedure duration, total radiation dose and contrast expenditure. In our trial it did not have any impact on the acute success rate of PV isolation or freedom from atrial fibrillation during 12-month follow-up.