Mesh catheter looks promising
FERRARA, ITALY. Currently radiofrequency (RF) pulmonary vein isolation (PVI) procedures employ 2 or 3 separate catheters for mapping, ablating and guidance. Manoeuvring 3 catheters in the small left atrium is very challenging indeed. Furthermore, the ablation rings burned around the pulmonary veins are produced one "dot" at a time, making the process time-consuming, while leaving the distinct possibility of gaps in the rings which can reinitiate afib. The use of the so-called cryo-balloon catheter makes it possible to produce an unbroken lesion ring, but still requires separate mapping.

Scientists and engineers at Bard Electrophysiology have now developed a new "mesh" catheter designed to perform both the mapping and ablation. The catheter looks somewhat like a metal-mesh balloon when expanded – it is, of course, deflated when it is advanced to the left atrium through a sheath (tube) inserted in the femoral vein. One part of the catheter is able to provide high definition voltage (potential) maps to guide the ablation and to check on its completeness, while a 6-mm band of electrodes (separated into 4 quadrants) delivers radiofrequency energy to create an unbroken ablation line around the edges of each pulmonary vein.

Italian EPs now report the first use of the Mesh-Bard catheter on a 45-year-old female afibbers who lapsed back into afib after an initially successful standard (CARTO) RF PVI. After remapping the left atrium, the EPs found evidence of lesion gaps in the left inferior and right superior veins. A repeat ablation was performed using the Mesh-Bard catheter. One single 5-minute RF application in each vein eliminated the offending potentials. The overall procedure time was 2 hours with only 12 minutes of fluoroscopy time. The patient was discharged after 2 days with no antiarrhythmic therapy and has been in normal sinus rhythm for 3 months.

More recently, an EP in Liverpool (Broadgreen Heart and Chest Centre) used the Mesh-Bard catheter on 2 AF patients and found it to be efficient and safe with a significantly shorter procedure time than current standard PVI procedures.

Pratola, C, et al. Paroxysmal atrial fibrillation ablation with the multipolar mapping and ablation catheter (Mesh-Bard). PACE, Vol. 31, June 2008, pp. 753-56

Editor's comment: The new Mesh-Bard catheter looks to be a well thought out device that should materially reduce procedure time while providing more complete lesions, thus hopefully, reducing the need for repeat ablations. However, there is, as yet, no long-term data as to its ultimate success rate, nor is there sufficient data to pronounce on its safety, especially in regard to pulmonary vein stenosis and phrenic nerve injury. It is also clear that while the catheter may be successful in dealing with paroxysmal afib, which originates in the pulmonary veins, there is no evidence that it is also useful in ablations involving persistent and permanent afib.