In vivo atrial ablations with a multielectrode RF system

We tested the performance of a multielectrode RF ablation system during in vivo procedures in the right atrium. A total of 75% of the RF applications resulted in complete lesions at the gaps between electrodes and 90% of them were considered potentially therapeutic, as they were transmural and expended along the intended contour. The average total procedure and fluoroscopy times were 83.4 and 5.9 min, respectively. Average power varied between 15 and 114 W. No sudden impedance rise occurred and no char was found by post-ablation inspection. The average impedance was 105/spl plusmn/16 /spl Omega/, with one electrode on, and 75/spl plusmn/12 /spl Omega/ when two electrodes were simultaneously on. The average maximal lesion length and width were 59.2/spl plusmn/11.7 and 7.1/spl plusmn/1.2-mm.