Use of a novel irrigated balloon catheter to generate continuous right atrial lesions by radiofrequency ablation.

Ablation catheters with multiple electrodes are effective for the creation of linear atrial lesions but are associated with an increased risk of coagulum formation. In an animal study, we used a novel 9Fr deflectable ablation catheter with two saline/foam electrode pocket covered with 20 mm tubing. Each pocket contained six 2-mm long electrodes with a 1-mm interelectrode distance. Bipolar electrograms between the 3 distal and 3 proximal composite electrodes were recorded, and the pacing threshold was determined before and after radiofrequency (RF) ablation. Long linear lesions were created by applying RF energy for 90 seconds at 50 W during saline irrigation (0.4 mL/sec) between 1) the superior vena cava (SVC) and inferior vena cava (IVC), 2) SVC, fossa ovalis, and IVC, 3) transverse loop from the crista terminalis to the tricuspid valve (TV), and 4) TV and the IVC. Continuous transmural lesions were created only in a minority of cases, and lesion gaps were noted in the free wall lesions. No coagulum formation was observed after RF energy delivery. A long lesion can be created in the right atrium by using an irrigated balloon catheter, but continuous lesion formation was achieved only in a minority of animals.