RESUMO
BACKGROUND: The impact of ECG gating during computed tomography (CT) acquisition of left atrium (LA) model on radiation dose, image quality and ablation event-free survival rate after catheter ablation (CA) of atrial fibrillation (AF) is not well defined. METHODS: Sixty-two patients with paroxysmal atrial fibrillation were randomized for two types of LA CT (with vs without ECG gating) before CA. Pulmonary veins isolation was performed in all patients. Patients were followed for 12 months after CA. RESULTS: There was no difference between the groups in CA length (131.61±32.57 vs 119.84±33.18 min; p=0.108), CA fluoroscopy time (4.48±2.19 vs 3.89±1.83 min; p=0.251), CA fluoroscopy dose (3.99±2.79 vs 3.91 vs2.91 Gy*cm2; p=0.735), visual data quality (1.77±0.88 vs 2.0±0.63; p=0.102) and registration error (2.42±0.72 vs 2.43±0.46 mm; p=0.612). We found a significant difference in CT Dose index (89.55±5.99 vs 19.19±4.33 mGy; p<0.0001) and Dose Length product (1438.87±147.75 vs 328.21±73.83 mGy*cm; p<0.0001). Twelve months after CA, 25 of 31 patients in the gated group and 24 of 31 patients in the non-gated group were free of AF (80.65 vs 77.42 %; p=0.838). CONCLUSION: ECG gating of computed tomography of LA before AF ablation burdens patients with a four times higher radiation dose while improving neither the quality of CT model or fusion of CT with the electroanatomic map. As a result, it has no significant impact on arrhythmia recurrence rate after ablation (Tab. 3, Fig. 3, Ref. 25).
