Background. Catheter ablation of accessory pathways using radiofrequency current has been demonstrated to be effective in patients with WPW, by using either the ventricular or atrial approach. Purpose of this study was: 1. to evaluate the transseptal approach technique for the ablation of left pathways and 2. to describe the electrogram criteria for the positioning of the ablation catheter at the left atrial site. Methods and Results. Fifty patients with WPW were treated by delivering RF energy at the left atrial site. In the first 35 patients the accessory pathway location was obtained by measuring the shortest stimulus-delta and His-delta intervals at 2 different atrial pacing rates and the shortest V-A interval either during ventricular pacing or spontaneous or induced reciprocating tachycardia. After reviewing the filtered (30-250 Hz), unipolar electrograms recorded in these patients, in the last 15 patients atrioventricular valve annulus was mapped in order to identify the accessory pathway (K) potential. The following time intervals were than measured: 1) from the onset of the atrial to the onset of the K potential (A-K); 2) from the onset of the delta wave to the onset of the K potential (delta-K); 3) from the onset of the K potential to the onset of the ventricular deflection (K-V). Attempts were considered successful when ablation (disappearance of the delta wave) occurred in <10 seconds. A-K (28 ± 8 vs 51 ± 14 msec. p <0.0001) and delta-K intervals (-18 ± 11 vs 2 ± 9 msec. p <0.O001) were significantly longer during unsuccessful than during successful attempts. The number of attempts in the last 15 patients was lower than in the initial 47 (9 ± 2 vs 3 ± 1 p <0.01). Furthermore, the success rate of the procedure in the first 35 patients was 87% (30/35), while it was 100% in the last 15 patients. Conclusions. Our data show that a short A-K and a negative delta-K interval recorded from the atrium are strong predictor of successful ablation of both left and right accessory pathways. Therefore, the identification of the K potential appears to be of paramount importance for an optimal positioning of the ablation catheter. Moreover the transseptal approach shows to be very safe and highly effective.
|Number of pages||9|
|Journal||New Trends in Arrhythmias|
|Publication status||Published - 1993|
- transseptal approach
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine