Electrophysiological predictors of effectiveness of RFA of persistent atrial fibrillation

Purpose: To determine the clinical and electrophysiological predictors influencing the course of the disease and the results of interventional treatment of patients (pts) with persistent atrial fibrillation (PsAf). Material and Methods: The clinical evaluation of the immediate and long-term results of radiofrequency ablation (RFA) of pulmonary veins (PV) and left atrium (LA) in pts with PsAf was made. From March 2008 to June 2009 74 catheter based procedures of RFA of PsAf were performed (mean age of the patients was 54.9+8.7 years, 50 males and 24 females). Mean duration of arrhythmia was 7.2±5.3 years, body mass index was 29.5±5.4. The vast majority of pts (83.7%) had hypertension and 19% of pts had coronary artery disease. The LV and heart valves function were assessed as well as the effect of structural heart disease on natural development of AF. Pts were divided into 3 groups according to the volume of LA (group I: LA volume up to 90 mL; group II: 90-130 mL; group III: 130 mL and more). Efficacy was assessed after one RFA procedure and after several RF procedures. Repeated RFA procedure was performed in 33.8% of pts, among them 73% of the recurrences were associated with the return of conduction from PV to LA. Results: Follow-up period was 12-50 months (mean 28±16 months). Sinus rhythm at discharge was recorded in 97.2% of pts. According to the first year of observation, after a single RFA procedure sinus rhythm was maintained in 66% of pts, among them 54% of pts underwent just circular isolation of PV in the antral site; in 37.8% of cases, circular antral isolation of PV was combined with linear lesions in the left inferior isthmuses of the heart. Redo procedure was necessary in 32.4% cases (7 pts from group I, 14 pts from group II, and 5 pts from group III). Thus, the effectiveness of radiofrequency pulmonary vein isolation after a single RFA of PsAf in the first 15 months of observation in all 3 groups was similar. During long-term follow-up (50 months), efficacy after a single RFA of PsAf declined to about 50% in group I; effectiveness in group II remained constant within 60% which was due to the emergence of incisional atrial tachyarrhythmias in group with LA volume 2, decreased myocardial contractility, mitral valve insufficiency and duration of arrhythmia more than 6 years), 80% of effectiveness can be reached by aggressive approach in the early stages of disease. Obviously redo procedures are mandatory to maintain sinus rhythm in long term follow-up. Pts with a long history of AF need additional linear lesions.