Comparative study of fluoroscopy and intracardiac echocardiographic guidance for the creation of linear atrial lesions.

BACKGROUND Recently, attempts have been made to cure atrial fibrillation by creating multiple linear atrial lesions with radiofrequency energy. Intracardiac echocardiography (ICE) offers imaging of endocardial anatomy and the ablation electrode-tissue interface not available with standard fluoroscopy. This study sought to prospectively compare fluoroscopic with ICE guidance for the creation of linear atrial lesions in a canine model. METHODS AND RESULTS The creation of 3 linear atrial lesions was attempted in each of 10 dogs, half guided by fluoroscopy alone and half by ICE. Coil-tissue contact was prospectively graded. After ablation, animals were euthanized, and the location and continuity of lesions were evaluated. ICE guidance led to a higher percentage of successful applications (P=0.02) and mean achieved temperature (P=0. 004). The contact scores of excellent, fair, and poor correlated well with successful energy delivery, mean temperature, and efficiency of heating (P<0.0001). In 25% of the blinded energy deliveries, the location, as determined by the ablation operator, differed from that of ICE. Pathological evaluation revealed improved lesion formation in the ICE-guided compared with the ICE-blinded group. Lesions were found outside the target areas in the ICE-blinded but not the ICE-guided group. CONCLUSIONS Compared with fluoroscopy, ICE guidance improved targeting, energy delivery, and lesion formation in this canine model. This study suggests that ICE guidance improves lesion formation and prevents energy delivery to potentially dangerous sites.