AT AF SYMPOSIUM 2017
ORLANDO (FRONTLINE MEDICAL NEWS) – A uniquely designed multielectrode radiofrequency ablation (RFA) balloon catheter system for the treatment of atrial fibrillation (AF) performed well in a first-in-man study.
The new ablation system is designed to provide the flexibility of conventional RFA devices in treating a broad array of AF triggers with the type of predictable energy delivery more closely associated with cryoballoon ablation, according to the principal investigator, Matthew G. Daly, MB, ChB, a cardiologist at Christchurch (New Zealand) Hospital.
The inflatable experimental device features 18 electrodes, a built-in camera, integrated mapping and pacing, and irrigation designed to reduce the risk of clot formation. On contact, the 12 electrodes situated on the equator of the spherical device, along with the six electrodes situated on the polar ends, are initially employed to select the ablation pattern. RFA can be delivered immediately through the same electrodes once proper contact is established using the built-in cameras for real-time visualization.
In this initial study, called AF-FICIENT, 18 patients were treated at four centers in New Zealand, South America, and Europe, Dr. Daly said at the annual International AF Symposium. The primary endpoint was safety and performance; the rate of successful pulmonary vein isolation (PVI), procedure times, and adverse events up to 30 days after treatment were also monitored.
No significant adverse events were encountered during the procedure or over the course of follow-up, according to Dr. Daly. PV isolation was achieved in 65 of 68 (96%) of veins treated. The average number of ablations required per PV isolation was 3.1. On average, it took 12 minutes to isolate all veins per patient, according to Dr. Daly, who characterized this as “respectable,” given that this was a novel technology being performed in a clinical study for the first time. The average balloon time was 1 hour 39 minutes.
For the patients followed through 6 months, 80% remain free of AF and off all medications.
“The system allowed for quick ablation without excessive catheter manipulations,” said Dr. Daly, suggesting that the performance was consistent with the theoretical advantages of a multipoint, single-shot design. Overall, Dr. Daly suggested that this device appears to permit RFA to be delivered in a manner that has been more closely related to the efficiency of cryoballoon ablation.
“The disadvantage, or perhaps the advantage, is that this is a device that requires a knowledge of electrophysiology,” said Dr. Daly, who said that physicians need to be familiar with isolating pulmonary veins in order to deliver the energy appropriately.
One of the theoretical advantages of this device over conventional RFA ablation is that it will provide more consistent power and temperature as long as appropriate contact is achieved. He noted that the variability in energy delivery according to angle or contact force has been one of the weaknesses of conventional RFA devices.
“Contact is king. This has always been true, but with this device the manufacturer recommended that we only applied energy when we thought contact was perfect,” Dr. Daly said. He acknowledged that he deviated from this recommendation in some instances, “but it turns out that if you have good contact, you get signal elimination almost immediately or at least within a few seconds,” but less dependable results when contact is compromised, such as in those instances where blood is an obstacle.
Because of its ability to deliver energy in a single shot at multiple points, this device has the potential to permit successful ablation with a shorter procedure time than with conventional RFA. Dr. Daly said this device is “light on its feet” and required relatively little time to maneuver into place. However, he said that procedure times in this initial study were longer because of inexperience and the need for “checking and rechecking” settings and positions.
Dr. Daly reported no industry relationships relevant to this study.