Pulmonary vein isolation with high-intensity focused ultrasound: results from the HIFU 12F study.
AIMS
High-intensity focused ultrasound (HIFU) applied via a balloon catheter (BC) is a novel technology for simplified pulmonary vein isolation (PVI). Safety and efficacy of the third generation HIFU-BC were assessed.


METHODS AND RESULTS
In 22 patients (10 male, mean age 65 +/- 6 years) with paroxysmal atrial fibrillation (PAF), a PVI during real-time PV spike registration and oesophageal temperature measurement was attempted. In 15 patients, a steerable sheath was used along with the HIFU-BC. In 67 of 83 PVs (81%), PVI was achieved exclusively using HIFU. Using the steerable sheath, the acute PVI rate rose from 50% (10/20 PVs) to 90% (57/63 PVs). In the latter, PVI was achieved with a single HIFU application in 60% (38/63 PVs) and mean sonication time of 11 +/- 7 s. The mean procedure time was 166 +/- 74 min including 58 +/- 25 min of HIFU-BC left atrial indwelling time. In four patients, peri-procedural complications occurred (one transient ischaemic attack, one phrenic nerve palsy, and two vascular access complications). During a median follow-up of 342 days (range 272-378 days), 71% patients remained free of any AF/AT recurrence without antiarrhythmic drugs after a single procedure.


CONCLUSION
The novel defocused 12F HIFU-BC used in conjunction with a steerable sheath allows for very rapid PVI in patients with PAF. The enthusiasm for rapid PVI is still dampened by the potential risk of collateral damage.