ECG-I Targeted Ablation for Persistent AF Not Responding to Pulmonary Vein Isolation Results of a Two Staged Strategy.

Atrial Fibrillation (AF) is a irregular heart rhythm associated with significant morbidity and mortality. Catheter ablation is a treatment where catheters are passed through the veins in the leg into the left atrium of the heart and lines of scar is delivered to disrupt tissue causing and maintaining atrial fibrillation. Current strategies involve isolating the pulmonary veins which have been shown to trigger and maintain AF. However, success rates for persistent AF lie in the region of 30-60% due to the drivers of AF residing elsewhere to the Pulmonary Veins antra. The ECG-I is a system which involves wearing a jacket with many ECG electrodes to record electrical activity from the surface of the body. A CT scan then shows where these electrodes are relative to the atria, and computer modelling is used to reconstruct the movements of electricity on the surface of the heart and therefore identifying where the drivers (tissue causing and maintaining AF) are located. Unfortunately, not all patients respond to PVI due to the drivers of AF being located in areas other than within the Pulmonary Veins. Identifying the drivers of AF is very difficult and the role they play has yet to be proved scientifically. PHENOTYPE AF is an ongoing clinical trial in which 100 patients with persistent AF are receiving cryoballoon pulmonary vein isolation for persistent AF (NCT03394404). Patients with recurrent AF or atrial tachycardia within 1 year following pulmonary vein isolation for AF within this trial will be recruited into this study. Up to 50 such patients who have failed Pulmonary Vein Isolation will be enrolled. These patients will undergo a second procedure at which time participants will undergo catheter ablation of drivers of AF and will then be followed up for 12 months.