Electroanatomic mapping to identify breakthrough sites in recurrent typical human flutter

The accuracy of conventional techniques in localizing previous radiofrequen cy (RF) ablation sites and th us breakthrough sites of recurrent atrial flu tter is somewhat limited. We investigated the role of electroanatomic mappi ng for identifying breakthrough sites or "gaps" at the tricuspid annulus an d inferior vena cava (IVC)/eustachian ridge isthmus to help RF ablation in patients with recurrent typical flutter. Twelve patients (8 men, 4 women, a ge 63 +/- 10 years) with recurrent typical atrial flutter were included in the study. An electroanatomic mapping system (CARTO) was used to create a v oltage map and activation and propagation patterns in the right atrium. Det ailed voltage, activation, and propagation mapping of the tricuspid annulus and IVC/eustachian ridge isthmus allowed precise identification of gaps in all 12 patients at the tricuspid annulus (eight sites), IVC ridges (two si tes), mid-isthmus region (one site), and tricuspid annulus and IVC ridges ( one site). Radiofrequency energy directed at these sites eliminated atrial flutter in all 12 patients, confirmed by noninducibility of atrial flutter and demonstration of conduction block during atrial pacing on either side o f the lesion lines. During a mean follow-up of 14.8 +/- 3.5 months (range 8 -19 months), paroxysmal atrial flutter recurred in only one patient and was subsequently treated with amiodarone, although this had been ineffective p rior to ablation. Electroanatomic mapping can precisely identify gaps in th e lesion line responsible for breakthrough of recurrent typical atrial flut ter at the tricuspid annulus and at the IVC/eustachian ridge isthmus. These sites can be targeted with RF ablation with a high degree of success.