3 The procedure
3.1 Percutaneous endoscopic laser balloon pulmonary vein isolation for atrial fibrillation (AF) aims to maintain normal heart rhythm. It uses laser ablation to isolate the electrical impulses originating in the pulmonary veins, which are thought to be responsible for triggering AF.
3.2 The laser balloon catheter comprises an inflatable balloon mounted on a catheter shaft, an endoscope lumen, and an optical fibre that can also deliver laser energy.
3.3 The procedure is done with the patient under general anaesthesia or sedation. A deflectable sheath introducer is inserted in the femoral vein and advanced into the left atrium through a trans‑septal puncture. A circular mapping catheter is introduced, which may need a second trans‑septal puncture. A balloon catheter is passed through the deflectable sheath and the balloon is inflated at the ostium of the target pulmonary vein. The endoscope tip is positioned at the proximal end of the balloon, allowing direct visualisation of the cardiac tissue and assessment of the degree of contact between the balloon and cardiac muscle. Laser energy is delivered around the circumference of the pulmonary vein to isolate the source of the abnormal electrical activity. The circular mapping catheter is then used to assess whether electrical isolation of the pulmonary vein has been achieved. Ablation and assessment are repeated for each pulmonary vein. During ablation of the right‑sided pulmonary veins, phrenic nerve pacing is done from the superior vena cava to monitor for phrenic nerve injury.