Radiofrequency modification of the right midseptal and posteroseptal areas was feasible and successful in 92% of patients with medically refractory paroxysmal atrial fibrillation.
Cohort (n=50)
Does radiofrequency catheter modification of the AV junction alter electrophysiological properties and control ventricular rate in patients with medically refractory paroxysmal atrial fibrillation?
Radiofrequency modification of the AV junction is a feasible strategy for rate control in medically refractory paroxysmal atrial fibrillation, acting via elimination of posterior input or partial injury to the compact node.
BACKGROUND: Mechanisms and changes of electrophysiological (EP) characteristics in successful radiofrequency (RF) modification of right midseptal and posteroseptal areas for controlling rapid ventricular response to atrial fibrillation (Af) are not clear. METHODS AND RESULTS: We studied 50 patients with medically refractory paroxysmal Af. Group 1 consisted of 40 patients without dual atrioventricular (AV) node physiology with modification sites located in the mid/posteroseptal area. Of the 40 patients, 36 had successful modification (follow-up of 14 +/- 8 months), and 3 had AV block. Late follow-up electrophysiological study (98 +/- 10 days) showed pattern 1 (67%) with prolongation of AV node effective refractory period (ERP, > or =40 milliseconds) and Wenckebach block cycle length (WBCL, > or =40 milliseconds); pattern 2 (22%) with prolongation of AH interval (> or =20 milliseconds), ERP, and WBCL; and pattern 3 (11%) without any change in AV node conduction parameter. Change in ventricular rate negatively correlated with change of WBCL in patterns 1 (r=-.691, P=.019) and 2 (r=-.90, P=.01). Group 2 consisted of 10 patients with dual AV node pathway; elimination of slow pathway property was performed. Late follow-up electrophysiological study (92+/-7 days) showed that change in ventricular rate negatively correlated with change in AV node ERP (r=-.926, P=.0001) and WBCL (r=-.969, P=.0001). Four patients without significant modification effect had success after RF energy was delivered to higher levels (follow-up, 15+/-7 months). CONCLUSIONS: RF modification of right mid/posteroseptal area is feasible in 92% of patients with paroxysmal Af. Mechanisms of successful modification might be elimination of posterior input and/or partial injury of the compact node. Furthermore, simple elimination of slow pathway might be inadequate for control of ventricular rate in patients with little difference in conduction properties between fast and slow pathways.
Chen et al. (Wed,) conducted a cohort in Medically refractory paroxysmal atrial fibrillation (n=50). Radiofrequency catheter modification of the right midseptal and posteroseptal areas was evaluated on Successful modification. Radiofrequency modification of the right midseptal and posteroseptal areas was feasible and successful in 92% of patients with medically refractory paroxysmal atrial fibrillation.
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