Catheter cardiac ablation treatment. Coloured 3D computed tomography (CT) scan of a semi-transparent view of the heart's left atrium from behind, showing a catheter used for cardiac ablation around the orifices of the pulmonary veins. The catheter is inserted remotely via a peripheral vein and passes through the inter-atrial septum to reach the left atrium. The treatment will create scars that disperse abnormal electrical signals in the heart that causes arrthymias. It is a method to treat atrial fibrillation (AF).