Electronanatomical mapping and ablation of atrial tachycardias with the CARTO system

Variable success rates in the ablation of atrial tachycardias using conventional electrophysiology have been achieved. There is no precise relation between P wave morphology in surface ECG and atrial electrophysiology, and this fact makes it more difficult to locate ectopic atrial foci. The CARTO system creates atrial activation maps that relate an anatomical location to an electrical potential. The aim of this study was to evaluate the efficacy of CARTO guided radiofrequency (RF) ablation of atrial foci. The population consisted of 10 consecutive patients with atrial tachycardia resistant to more than 2 drugs, 7 female, mean age 45 +/- 12 years. CARTO activation maps were constructed based on atrial tachycardia or premature beats. Radiofrequency energy was applied to the earliest activation zone. Immediate success was defined as suppression of ectopic atrial activity. Ectopic foci were located on the ostium of the coronary sinus (3 patients), crista terminalis (1 patient), right atrial appendage (1 patient), interatrial septum (1 patient) and in the pulmonary veins (4 patients). The activation maps contained 85 +/- 35 points. The number of RF applications ranged from 1 to 11 (mean 4). Immediate and 6 month success rate was 90%. We were not able to treat one patient with a focus in the right atrial appendage. No attempt was made to limit procedure or fluoroscopy time in our study. Nonetheless all procedures lasted less than 150 min, and fluoroscopy times were less than 30 minutes.

The CARTO system precisely located ectopic atrial foci, allowing a high success rate in the ablation of focal atrial tachycardias.