Mapping of atrial activation with a noncontact, multielectrode catheter indogs

Background-Endocardial mapping of sustained arrhythmias has traditionally b een performed with a roving diagnostic catheter. Although this approach is adequate for many tachyarrhythmias, it has limitations, The purpose of-this study was to evaluate a novel noncontact mapping system for assessing atri al tachyarrhythmias. Methods and Results-The mapping system consists of a 9F multielectrode-arra y balloon catheter that has 64 active electrodes and ring electrodes for em itting a locator signal. The locator signal was used to construct a 3-dimen sional right atrial map; it was independently validated and was highly accu rate. Virtual electrograms were calculated at 3360 endocardial sites in the right atrium. We evaluated right atrial activation by positioning the ball oon catheter in the mid right atrium via a femoral venous approach. Experim ents were performed on 12 normal mongrel dogs. The mean correlation coeffic ient between contact and virtual electrograms was 0.80+/-0.12 during sinus rhythm. Fifty episodes of atrial flutter induced in Il animals were evaluat ed. In the majority of experiments, complete or almost complete reentrant c ircuits could be identified within the right atrium. Mean correlation coeff icient between virtual and contact electrograms was 0.85+/-0.17 in atrial f lutter. One hundred fifty-six episodes of pacing-induced atrial fibrillatio n were evaluated in 11 animals. Several distinct patterns of right atrial a ctivation were seen, including single-activation wave fronts and multiple s imultaneous-activation wave fronts. Mean correlation coefficient between vi rtual and contact electrograms during atrial fibrillation was 0.81+/-0.18. The accuracy of electrogram reconstruction was lower at sites >4.0 cm from the balloon center and at sites with a high spatial complexity of electrica l activation. Conclusions-This novel noncontact mapping system can evaluate conduction pa tterns during sinus rhythm, demonstrate reentry during atrial flutter, and describe right atrial activation during atrial fibrillation. The accuracy o f electrogram reconstruction was good at sites <4.0 cm from the balloon cen ter, and thus the system has the ability to perform high-resolution multisi te mapping of atrial tachyarrhythmias in vivo.