Incidence and Factors Associated With the Occurrence of Pulmonary Vein Narrowing After Cryoballoon Ablation

The purpose of this study was to provide an updated worldwide report on the methods, efficacy, and safety of catheter ablation of atrial fibrillation (AF). A questionnaire with 46 questions was sent to 521 centers from 24 countries in 4 continents. Complete interviews were collected from 182 centers, of which 85 reported to have performed 20,825 catheter ablation procedures on 16,309 patients with AF between 2003 and 2006. The median number of procedures per center was 245 (range, 2 to 2715). All centers included paroxysmal AF, 85.9% also included persistent and 47.1% also included long-lasting AF. Carto-guided left atrial circumferential ablation (48.2% of patients) and Lasso-guided ostial electric disconnection (27.4%) were the most commonly used techniques. Efficacy data were analyzed with centers representing the unit of analysis. Of 16,309 patients with full disclosure of outcome data, 10 488 (median, 70.0%; interquartile range, 57.7% to 75.4%) became asymptomatic without antiarrhythmic drugs and another 2047 (10.0%; 0.5% to 17.1%) became asymptomatic in the presence of previously ineffective antiarrhythmic drugs over 18 (range, 3 to 24) months of follow-up. Success rates free of antiarrhythmic drugs and overall success rates were significantly larger in 9590 patients with paroxysmal AF (74.9% and 83.2%) than in 2800 patients with persistent AF (64.8% and 75.0%) and 1108 patients with long-lasting AF (63.1% and 72.3%) (P<0.0001). Major complications were reported in 741 patients (4.5%). When analyzed in a large number of electrophysiology laboratories worldwide, catheter ablation of AF shows to be effective in approximately 80% of patients after 1.3 procedures per patient, with approximately 70% of them not requiring further antiarrhythmic drugs during intermediate follow-up.

The purpose of this study was to conduct a worldwide survey investigating the methods, efficacy, and safety of catheter ablation (CA) of atrial fibrillation (AF). A detailed questionnaire was sent to 777 centers worldwide. Data relevant to the study purpose were collected from 181 centers, of which 100 had ongoing programs on CA of AF between 1995 and 2002. The number of patients undergoing this procedure increased from 18 in 1995 to 5050 in 2002. The median number of procedures per center was 37.5 (range, 1 to 600). Paroxysmal AF, persistent AF, and permanent AF were the indicated arrhythmias in 100.0%, 53.0%, and 20.0% of responding centers, respectively. The most commonly used techniques were right atrial compartmentalization between 1995 and 1997, ablation of the triggering focus in 1998 and 1999, and electrical disconnection of multiple pulmonary veins between 2000 and 2002. Of 8745 patients completing the CA protocol in 90 centers, of whom 2389 (27.3%) required >1 procedure, 4550 (52.0%; range among centers, 14.5% to 76.5%) became asymptomatic without drugs and another 2094 (23.9%; range among centers, 8.8% to 50.3%) became asymptomatic in the presence of formerly ineffective antiarrhythmic drugs over an 11.6+/-7.7-month follow-up period. At least 1 major complication was reported in 524 patients (6.0%). The findings of this survey provide a picture of the variable and evolving methods, efficacy, and safety of CA for AF as practiced in a large number of centers worldwide and may serve as a guide to clinicians considering therapeutic options in patients suffering from this arrhythmia.

Atrial fibrillation (AF) is frequently initiated from pulmonary veins (PVs), but little is known of the electrophysiological properties of PVs. Two groups were studied: 28 patients (49+/-13 years old) with paroxysmal AF and 20 control patients (49+/-14 years old) without AF. Effective and functional refractory period and conduction time from PV to left atrium (LA) were compared in the 2 groups by use of programmed stimulation with a single extrastimulus in the PVs and LA. In the AF group, the venous effective refractory periods (ERPs) were shorter than that of the LA: 185+/-71 versus 253+/-21 ms, P<0.001, whereas in the control group, they were longer (282+/-45 versus 253+/-41 ms, P=0.009). The venous ERPs and functional refractory periods in patients with AF were also shorter than that observed in control subjects (185+/-71 versus 282+/-45 ms and 210+/-77 versus 315+/-43 ms, respectively, P<0.001), whereas LA ERPs were not significantly different. Decremental conduction in PVs was more frequent (93% versus 56%, P=0.01) and had a greater increment (102+/-65 versus 42+/-40 ms, P<0.001) in patients with AF. Finally, AF was more frequently induced when pacing was performed in PVs (22 of 90) versus LA (1 of 81) in patients with AF (P<0.001). The PVs of patients with AF exhibited distinctive electrophysiological properties, which were strikingly different from those of patients devoid of AF, potentially explaining their arrhythmogenicity.