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Letter to the Editor

The editorial comment by Jais et al.1 on our article published in the July 2000 issue of the Journal is very comprehensive. However, we would like to provide some information about the controversial points. First, the comments on our high incidence of focal atrial  brillation (AF) from the right atrium (RA) are incorrect (page 758, paragraph 4).1 The study population reported by Lee et al.2 was not a consecutive patient series. In addition, the information about the incidence of RA foci reported by other laboratories is not correct. Wharton had a high incidence of non-pulmonary vein (PV) focal AF (31%). Natale et al.4 also found a high incidence of RA foci (37.5%). According to our presentation at the Boston meeting,5 the incidence of non-PV origin of focal AF in our laboratory was 15% of 167 consecutive patients (Table 1). Tsai et al.6 from our laboratory also reported only 6% of AF initiators from the superior vena cava. Second, more information is necessary regarding the editorial comment on radiofrequency energy and PV stenosis. The Bordeaux group uses 50% narrowing of PV diameter by angiography as the de nition of stenosis; however, we use increased PV  ow velocity . 102 cm/ sec, measured by transesophageal echocardiography, as the de nition of stenosis.8 Thus, the results of the two studies are not comparable. To the best of our knowledge, the sensitivities of different follow-up tools for detection of PV stenosis, such as angiography, transesophageal echocardiography, intracardiac echocardiography, spiral computed tomography, and three-dimensional magnetic resonance imaging, have not been de ned. More prospective studies are necessary to prove the optimal ablation method, including the energy source, energy parameter, and approach technique (focal, segmental, and circumferential ablation) during ablation of AF initiating from a focal area.