<![CDATA[AV junction ablation has been proven effective to treat symptomatic atrial fibrillation refractory to antiarrhythmias or fail of pulmonary vein isolation. However, about 15% of conventional right-sided approach AV junction ablation failed to produce complete heart block. This study aimed to characterize His bundle potential at ablation site during conventional or left-sided approach of AV junction ablation. Twenty symptomatic AF patient (age of 60.5 ± 9.28 and 11 are females) underwent conventional AV junction ablation. If 10 applications of radiofrequency energy are failed, then the ablation was performed by left-sided approach. Seventeen patients are successfully ablated by conventional approach. In 3 patients, conventional was failed but successfully ablated by left-sided approach. The His bundle amplitude at ablation site was significantly larger in left-sided than correspondence right-sided (16.0 ± 4.99 mm vs. 6.9 ± 4.02 mm respectively, p = 0.001, 95% CI -14.0 to -4.3). ROC analysis of His bundle potential amplitude recorded from right-sided revealed that cut off point of > 4.87 mm given the sensitivity of 81.3% and specificity of 53.8% for successful right-sided approach of AV junction ablation. In case of failed conventional approach, the left-sided approach is effective for AV junction ablation. An early switch to the left-sided approach may avoid multiple RF applications in patients with a low amplitude His-bundle potential (< 4.87 mm). (Med J Indones 2006; 15:109-14)Keywords: Atrial fibrillation, AV junction ablation, left-sided approach]]>
