Influence of right atrial structure on outcome of radio-frequency catheter ablation for common atrial flutter

Radiofrequency catheter ablation (RFCA) targeting the cavotricuspid isthmus is usually an effective treatment for common atrial flutter (AFL), except in a small subset of patients and the reason for this has yet to be elucidated. The present study investigated the relationship between the outcome of RFCA for common AFL and the anatomy of the right atrium as seen on angiography. Twenty consecutive patients who underwent RFCA for common AFL were divided into 2 groups according to the results of RFCA. Group A comprised 13 patients whose AFL was abolished, fulfilling the criteria of success by the conventional catheter approach, and group B comprised 7 patients whose AFL could not be abolished according to the criteria for success (n=4) or was abolished following an additional superior vena cava approach (n=3). On angiography, the cavotricuspid isthmus was longer (3.5+/-0.5 vs 2.2+/-0.6 cm) and deeper (0.94+/-0.35 vs 0.49+/-0.19 cm) in group B than in group A (both p<0.01). The height of the eustachian valve was also greater in group B than in group A (1.4+/-1.1 vs 0.48+/-0.48 cm, p<0.02). These results suggest that the anatomical structure of the cavotricuspid isthmus affects the outcome of RFCA for common AFL.