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THE USE OF SIMULTANEOUS BIPOLAR AND UNIPOLAR REGISTRATION FOR MAPPING SLOW PATHWAY OF ATRIOVENTRICULAR JUNCTION

The purpose: We tried to define safety and efficiency of simultaneous bipolar and unipolar registration for mapping of slow pathway.

Methods: The study group consisted of 16 consecutive patients (9 men and 7 women, age 39,0 ± 3,4 years) with atrioventricular nodal reciprocated tachycardia (AVNRT), whose target site was determined by simultaneous registration bipolar and unipolar slow pathway potentials. All patients (pts) underwent electrophysiologic study (EPS). Diagnostic catheters were inserted from the right and left femoral veins and its set on the right ventricle apex, right-high atrium and His-region for registration potentials and pacing. The means of Effective Refractory Period (ERP) of a fast and slow pathway, Wenchebach point, modes of tachycardia induction and termination were determined. The tachycardia was diagnosed as AVNRT by classic criteria. The target for RFA was defined on the basis of simultaneous bipolar and unipolar slow pathway registration during sinus rhythm and atrial stimulation with cycle length 500-600 ms. Three radiofrequency applications with standard parameters (duration, power, temperature) in the area of interest near CS os region were performed. The successful ablation was estimated on the signs of a slow pathway modification: absence of induction AVNRT after each RFA application, occurrence of accelerated rhythm from А VJ during ablation, change of value ERP AVJ. In the case of unsuccessful ablation we found other site for RFA. Aggressive transesophageal EPS protocol for induction AVNRT after atropine administration was performed 3 days later.

Results: There are no cases of arrhythmia relapse during 5 months follow-up without antiarrhythmic therapy. We registered six types unipolar and bipolar potential morphology and delivered radiofrequency energy in this region. The ablation guided by potential №1 was effective in 14 cases after first application. Bipolar potential registered in this area did not correspond to classical criteria of slow pathway potential. The application in the site of registration of potential №2 was effective in 2 cases, and in sites №№ 3-6 was not effective. Appearance of potential №1 morphology only during atrial stimulation was noted in five cases. The RFA was also successful in these sites. Ten pts were registered the single atrial ECHO without AVNRT induction at programmed stimulation, the values of ERP AVJ and Wenchebach point have changed at 13 pts, accelerated junctional rhythm was observed at 4 pts and low atrial rhythm was observed at 5 pts during RFA.

Conclusion: Slow pathway ablation guided simultaneous bipolar and unipolar potentials registration is effective and safety method for treatment AVNRT. The morphology of the bipolar potential in site of slow pathway modification and based on the unipolar potential registration differs from classical bipolar criteria.