USE OF TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN RADIOFREQUENCY CATHETER ABLATION IN CHILDREN AND ADOLESCENTS

OBJECTIVE: To assess the utility of transesophageal echocardiography ( TEE) in radiofrequency (RF) catheter ablation of left-sided atrioventr icular bypass tracts. PATIENTS: RF catheter ablation was assisted with TEE in 13 children and adolescents aged 9.9 to 16.3 years (mean 13.3) . Results were compared with 21 procedures done in 19 patients (age 8. 8 to 18 years, mean 14.5) without TEE assistance. MAIN RESULTS: RF abl ation success rate was similar in both groups (90% to 92%). Successful RF ablation required 6+/-8 RF pulses in the TEE group and 10+/-7 RF p ulses in the non-TEE group (nonsignificant). Fluoroscopy time was 36+/ -17 mins and 54+/-28 mine, respectively (P=0.03). Characteristic tenti ng of the fossa ovalis by a transseptal needle was easily visualized w ith TEE. TEE allowed for precise positioning of the ablation electrode on the mitral valve ring. At the successful site, the ventriculoatria l (VA) time was 42+/-10 ms in the TEE group and 52+/-16 ms in the non- TEE group (P=0.05). The atrioventricular (A:V) ratio was 1.1+/-1.1 and 1.2+/-0.7, respectively (nonsignificant) with a large scatter of indi vidual values. Electrogram amplitudes and VA conduction times that are desirable for RF ablation were also recorded on the mitral valve leaf lets and over the coronary sinus. TEE visualized thrombus formation in the right atrium (three patients) and in the left atrium (two patient s). CONCLUSIONS: TEE should be strongly considered as supplemental ima ging for RF ablation of left sided bypass tracts performed under gener al anesthesia in children and adolescents. TEE renders transseptal pun cture safe. TEE may decrease fluoroscopic exposure. TEE confirmation o f the ablation catheter tip in the angle between the coronary sinus an d the mitral valve ring may allow limitation of unnecessary RF lesions and injury to the mitral valve. The demonstration of early intracardi ac thrombus formation argues for prompt and full heparinization after transseptal puncture.