The Correlation Between The Slow Pathway Conduction Interval And The Successful Ablation Traget: An Clinical Implication To Show Pathway Ablation In Atrioventricular Nodal Reentry Tachycardia

PURPOSE: To study the correlation between the properties of slow pathway (SP) conduction and the successful ablation targets in patients with AV nodal reentrant tachycardia (AVNRT).METHODS AND RESULTS: fifty-six consecutive patients(49.89?17.29ys, 26 males) with typical AVNRT were studied. 27 patients (group A: treated with standard electrogram-anatomic guided mapping method)were compared with the Group B(29 patients, were predetermine the ablation target according the AH interval of SP conduction). In group A, the distance between the catheters of His-bundle and the coronary sinus (His-CS) was measured in the right anterior oblique (RAO) 30?view. The distance from the His-bundle catheter to the successful ablation target (His-Abl) and the proportion of the ablation target in Koch's triangle (His-Abl/His-CS) was also measured. The mean His-CS and His-Abl were 23.12 ?.90 mm and 14.87 + 4.09 mm, respectively. The shortest AH interval of SP conduction (S-AH) were 154~396ms, 282.37 ?1.84ms; the longest AH interval of SP conduction (L-AH) were 274~ 592ms, 367.67 + 73.39ms; and the AH interval during AVNRT (T-AH) were 200~440ms, 322.70 +55.66ms. The distance of His-Abl is positively correlated with the S-AH (r = 0.465, P < 0.02) and the L-AH (r=0.541, P < 0.005), but it is not correlate with the T-AH (r = 0.049, P>0.20) . The His-CS and His-Abl/His-CS have no correlation with the interval of SP conduction. According to the result of study in group A, Group B ( 29 patients, 49.75 + 16.83, 14males) were predetermine the ablation target according the S-AH and L-AH. The longer AH interval of SPconduct, the longer distance of His-Abl. In group B, the mean expose time and mean RF applications were less than group A respectively, 28.06 ?18.07 vs. 36.76+19.22 min, P < 0.01,and 1.72 ?1.25 vs. 2.81 ?.84, P < 0.05.CONCLUSION: The SP conduction interval is correlation with the His-Abl. The SP conduct longer AH interval, there was longer distance from successful ablation target to His-bundle.The long distance was the one of the mechanism of slow conduction in SP.According to the slow pathway conduction interval, we can predetermine the ablation target in AVNRT. Compared with standard method, it can shorten expose time and RF application.