Abstract Background radio frequency catheter ablation (CA) is an effective therapy for atrial fibrillation (AF). Some authors have described a potential relationship between the presence of areas of fibrosis in the left atrium (LA) and the success of CA, nevertheless there is a lack of multicenter studies in this field. Objective the aim of our study was to assess the relationship between the of presence of low voltage areas of the LA detected during subtrate mapping at the time of the procedure and recurrences of AF after CA. Methods we analyzed 214 patients of the SMOP-AF (Substrate Mapping as Outcome Predictor in Atrial Fibrillation Ablation), a prospective multi-centric study enrolling patients with both paroxysmal and persistent AF undergoing a first radio-frequency CA procedure. High-density mapping was performed in sinus rhythm using the CARTO system before performing pulmonary vein isolation. Areas with less than 0,5 mV on mapping were defined as low voltage zone (LVZ), while between 0,5 mV and 1,5 mV intermediate voltage zone (IVZ). IVZ and LVZ were expressed as a percentage of the LA surface. Comparisons were made by Pearson correlation, cross-tables and Chi-square test or Student T test. Results the mean age of the enrolled population was 59±9 years, left ventricular ejection fraction was 59±9%, 86.4% of the pts had tested at least one anti-arrhythmic drug. Persistent atrial fibrillation was present in 10.3% of patients. The rate of documented AF recurrence at 3 months was 15,3% (n=29). There was a statistical significant correlation between the presence of IVZ and the rate of recurrences at 3 months (r=0.16, p value 0.03). Patients with IVZ greater than 4% of the left atrium surface showed a higher risk of recurrences (19.5% vs. 8,7%, p value 0.04). No statistical difference was observed in other procedural variables (number of lesions, contact force, force-time integral) among patients with or without recurrences. Conclusion Our study showed a relationship between CA short-term success rate and the presence of areas of intermediate voltage zone detected with high-density substrate mapping at the time of the procedure. The presence of areas of intermediate voltage zone greater than 4% of the LA determines a 2.5 folds increased risk of short-term recurrence. Our data needs to be confirmed in a longer follow-up.
Background: patients with long-lasting permanent atrial fibrillation (AF) are often destined to remain in AF life-long. In this cohort outcomes of ablation techniques are disappointing, with 20 –74% success rate and 30 –50% repeat procedure. The adjunctive clinical benefit of targeting multiple right and left atrial (LA) sites beyond the pulmonary vein (PV)-LA junction with the aim of achieving acute AF termination has not been prospectively evaluated in a randomized study. Methods and results: 60 patients with permanent atrial fibrillation of more than 1 year duration, with early recurrence after electrical cardioversion and medical therapy with one or more antiarrhythmic agents were enrolled (mean age 59±10, mean AF duration 60 months, mean LA dimension 44±7 mm, left ventricular EF >40% in all) and randomized to standard circumferential PV ablation (CPVA, control group, N=30) or an extended CPVA schema targeting also inferior LA, atrial septum, LA appendage, coronary sinus and right atrium (test group, N=30). In the test group the procedural endpoint was sinus rhythm (SR) restoration by radiofrequency energy; at each step average cycle length was measured and ablation was stopped if patient gained SR. In the control group the standard CPVA technique was applied. All patient transmitted daily transtelephonic ECG strips whereas at 3, 6 and 12 months an echocardiogram and a 48 hour Holter was obtained. Antiarrhythmic drug therapy was continued for 3 months after ablation in both group (blanking period in which patients were allowed to undergo electrical cardioversion). AF terminated in 5% and 55% of control and test subjects; mean procedure duration was 66 and 88 minutes in the 2 groups; No significant complications occurred in both groups. After a mean follow-up of 4 months, 67% of control patients were sinus as compared with 83% in the test group (p<0.05). 2 and 2 patient undergoing a repeat procedure for recurrent AF for AF (N=2) and AT (N=2). Acute AF termination was the strongest endpoint of SR maitainance (p<0.01) Conclusion: Preliminary data show that a modified CPVA ablation strategy in patients with permanent AF is associated with acute AF termination in 55% of patients and achieves medium term restoration and maintenance of sinus rhythm in 83% of patients.
Introduction: There is limited information describing late changes in the electroanatomic characteristics of the left atrium (LA) associated with recurrence after an anatomical circumferential pulmonary vein ablation (CPVA) for atrial fibrillation (AF). Methods and Results: Forty‐seven patients (57 ± 8 years) undergoing a repeat ablation after CPVA were included. Using an electroanatomic mapping system, we measured the bipolar voltage by averaging points in the pulmonary vein (PV)‐LA junction and four other LA sites. Conduction velocity and AF cycle length (AFCL) were also measured and the results are compared with the first procedure. After an initial decrease observed at the end of the first procedure, voltage and conduction velocity returned to intermediate values in all LA sites, with lower voltage at the LIPV antrum (P = 0.004), and lower conduction velocity across the LIPV and RSPV (P < 0.001). Conduction gaps were more prevalent at the septal aspect of the right PV encircling lines (85%), between the left atrial appendage (LAA) and the LSPV (70%) and lines at the posterior wall (71%). There was a nonsignificant increase in AFCL, with a more widespread distribution of organized electrograms (32.4% vs 46.6%). Conclusion: Recurrence after CPVA is associated with a reverse process of voltage and conduction velocity increase across ablated areas, especially the PV‐LA junction, and is related to the presence of conduction gaps, which are distributed mostly at the septal aspect of the lines encircling the right PVs and at the LAA‐LSPV area. Organization of atrial electrograms seen during AF ablation is maintained at a repeat procedure.
