Documentation of pulmonary vein isolation improves long term efficacy of persistent atrial fibrillation catheter ablation.

BACKGROUND: The aim of this study was to investigate the efficacy of catheter ablation in the treatment of persistent atrial fibrillation (AF) and the predictors of arrhythmia recurrence. METHODS: Absence of atrial tachyarrhythmia (AT) recurrence during a mid-term follow-up was correlated with several clinical and procedural characteristics in a population of 82 patients aged 20-70 years who had experienced at least one documented relapse of persistent AF during a single trial of antiarrhythmic drug therapy. Electrophysiological success of ablation was declared when all identified PVs were isolated (confirmation of entry and exit block). Patients were followed for a maximum of 24 months after the blanking period with outpatient visits, ECG recordings, 24-hour Holter monitoring, and weekly transtelephonic monitoring for 30s. RESULTS: Electrophysiological success was documented in 38/82 (46.3%) patients. During a mean follow-up of 24.7 ± 4.2 months, 69/82 (84.1%) patients presented at least one episode of AT after the 2 month blanking period. According to univariate and multivariate logistic regression analyses, only an electrophysiologically successful ablation significantly correlated with the absence of documented AT relapse (OR 5.32, 95% CL 1.02-27.72; p=.0472). CONCLUSIONS: Mid-term outcome of a single procedure of catheter ablation without the adjunction of antiarrhythmic drug therapy is poor in patients with persistent AF. Documented PV isolation is useful to increase the success rate of circumferential PV ablation even in persistent AF patients.

Appropriate therapies predict long-term mortality in primary and secondary prevention of sudden cardiac death.

BACKGROUND: Less than 50% of patients implanted with an implantable cardioverter-defibrillator (ICD) receive device therapy during the follow-up. The aim of our study was to prospectively evaluate the predictive role of appropriate ICD therapy on long-term survival of patients implanted for primary or secondary sudden death prevention. METHODS: From 2002 to 2003, 139 consecutive patients [mean age 66±9 years, male 77%, ischemic heart disease 56%, New York Heart Association functional class >II (74%), primary prevention 74%, mean left ventricular ejection fraction 30±9%, cardiac resynchronization ICD 65%] were enrolled. We collected and evaluated device therapies for at least 18 months and recorded survival status for more than 5 years. RESULTS: Over a median follow-up of 18 months, 54 (39%) patients received at least one ICD intervention, with 28 patients receiving only appropriate ICD therapies, 13 only inappropriate therapies and 13 receiving both therapies. At a mean follow-up of 63±12 months, 30 deaths occurred in 130 patients (23%); for nine patients, we had no survival status information. Death was classified as cardiac in 22 (73%) patients, the most common cause was progressive heart failure. In a Cox proportional regression model, an appropriate ICD therapy was associated with a significant increase in the subsequent risk of death (hazard ratio 3.02, P=0.003). CONCLUSION: In patients implanted with ICD or cardiac resynchronization therapy with ICD devices, for primary or secondary sudden cardiac death prevention, appropriate ICD therapy predicts a three-fold greater risk of death.

Feasibility and efficacy of electrical cardioversion after cardiac resynchronization implantation in patients with permanent atrial fibrillation.

PURPOSE: Patients with permanent atrial fibrillation (AF) who undergo cardiac resynchronization therapy (CRT) may spontaneously recover sinus rhythm during follow-up. We tested the feasibility and efficacy of electrical cardioversion attempted after 3 months of CRT in patients with permanent AF and measured the long-term maintenance of sinus rhythm. METHODS: Twenty-eight consecutive patients with permanent AF in whom CRT defibrillators had been implanted were scheduled for internal electrical cardioversion after 3 months (group A) and were compared with a control group of 27 patients (group B). RESULTS: In group A, 22 patients (79 %) were eligible for cardioversion; sinus rhythm was restored in 18 (82 %) of these, with no procedural complications. After 12 months, 16 patients (58 %) in group A were in sinus rhythm, compared with one group B patient who spontaneously recovered sinus rhythm (4 %, p < 0.001). On 12-month evaluation, ejection fraction had improved in both groups, but a reduction in left ventricular end-systolic volume was recorded only in group A patients (p = 0.018 versus baseline). CONCLUSIONS: In patients with permanent AF, the rhythm control strategy consisting of internal cardioversion, performed by means of the implanted cardioverter-defibrillator after 3 months of CRT, was associated with a high rate of sinus rhythm resumption on long-term follow-up and with a better echocardiographic response to CRT than that seen in patients treated according to a rate control strategy.

Clinical and technical determinants of long-term performance of coronary sinus leads.

OBJECTIVES: Little is known about coronary sinus lead performance in patients with cardiac resynchronization therapy devices. We evaluated the impact of clinical and technical parameters on coronary sinus lead performance over long-term follow-up. METHODS: From February 1999 to July 2004, 235 patients (181 men; mean age, 68 +/- 9 years; mean left ventricular ejection fraction, 26.5 +/- 6.5%; idiopathic dilated cardiomyopathy, 49%; ischemic, 48%; and other cause, 3%) underwent cardiac resynchronization therapy (pacemaker or defibrillator) implantation. RESULTS: On implantation, the only statistically significant difference was observed in mean pacing impedance, which was lower for unipolar leads than for bipolar leads (763 +/- 250 vs. 847 +/- 270 Omega, P = 0.02), and lower in patients with ischemic cardiomyopathy than in those with idiopathic cardiomyopathy (758 +/- 204 vs. 837 +/- 291 Omega, P = 0.03). After a mean follow-up of 41.7 +/- 14.7 months, a significant decrease was observed in mean pacing impedance (from 811 +/- 261 to 717 +/- 284 Omega, P = 0.0026) and mean R-wave amplitude (from 13.2 +/- 6.7 to 10.5 +/- 5.5 mV, P = 0.002), whereas the mean pacing energy threshold increased from 3.6 +/- 10.4 to 9.5 +/- 28 microJ (P = 0.004). On analysis of variance, unipolar lead (P = 0.016) and posterior coronary sinus position (P = 0.049) were related to a greater energy threshold increase. On multivariate analysis (Cox regression), only posterior coronary sinus lead position (P = 0.013) proved to be an independent predictor of long-term significant increase in the stimulation energy threshold. CONCLUSION: Over the long-term follow-up of coronary sinus leads, pacing impedance and R-wave amplitude decreased, whereas the energy threshold increased; unipolar leads and posterior lead location in the coronary sinus were related to a greater energy threshold increase.

Does catheter ablation cure atrial fibrillation? Single-procedure outcome of drug-refractory atrial fibrillation ablation: a 6-year multicentre experience.

Aims In the last decade, several approaches to ablating triggers and substrates of atrial fibrillation (AF) have been developed. However, most studies have reported data only on short- or medium-term follow-up. The aim of this study was to investigate whether the 1-year efficacy of catheter ablation for AF is predictive of long-term clinical success. Methods and results Between February 2001 and October 2003, 229 consecutive patients affected by drug-refractory paroxysmal or persistent AF underwent a single radiofrequency catheter ablation procedure (anatomical approach in 146 patients and electrophysiologically guided approach in 83 patients). Of these patients, 177 (mean age 59.1 +/- 10.5 years, 57.6% with paroxysmal AF) were free from any atrial arrhythmia recurrence after 12 months. These 177 patients were subsequently followed up for at least another 24 months, by means of electrocardiogram and 24 h Holter monitoring. After a mean follow-up of 49.7 +/- 13.3 months (range 36-83 months), 58.2% of the patients were free from any atrial arrhythmia recurrence (39.5% without antiarrhythmic drugs). The actuarial atrial arrhythmia recurrence rate was 13.0% at 2 years, 21.8% at 3 years, 35.0% at 4 years, 46.8% at 5 years, and 54.6% at 6 years. Atrial arrhythmia-free survival was similar in patients with paroxysmal or persistent AF, with and without antiarrhythmic drugs during the follow-up, who underwent electrophysiologically guided pulmonary vein (PV) isolation or anatomical PV ablation. Conclusion Even patients in whom catheter ablation prevents AF recurrence for 1 year should not be considered 'cured', since >40% of them will suffer AF recurrence over a long-term clinical follow-up.

Cardiac resynchronization therapy: a review of CRT-D versus CRT-P.

Current evidence-based guidelines recommend an implantable cardioverter-defibrillator for the primary prevention of sudden cardiac death in selected patients with impaired left ventricular function, and cardiac resynchronization therapy for improvement of symptoms and survival in selected patients with impaired left ventricular function and abnormal ventricular conduction. Many patients may be eligible for both treatments, but it does not necessarily follow that such patients would obtain additional benefit from the combined treatment over one treatment alone. A simple pragmatic approach would be to use resynchronisation therapy, in order to reduce symptoms and extend life in patients with New York Heart Association class III or IV heart failure, with the addition of an implantable cardioverter-defibrillator left to clinical judgment on an individual basis when additional indications exist. When such an addition is contemplated the hypothesized incremental benefits in survival would need to be balanced by the possible increase in morbidity owing to, for example, inappropriate shocks.

Role of pulmonary veins isolation in persistent atrial fibrillation ablation: the pulmonary vein isolation in persistent atrial fibrillation (PIPA) study.

BACKGROUND: The role of pulmonary veins (PV) isolation in patients with persistent atrial fibrillation (AF) is still debated. The aim of this study was to evaluate the adjunctive role of PV isolation in patients with persistent AF who underwent circumferential PV ablation (anatomical approach). METHODS: We treated 97 consecutive patients presenting with drug-refractory persistent AF by an anatomical approach (group A, n = 36, mean age = 60 +/- 8 years, 29 males) or an integrated approach (group B, n = 61, mean age 59 +/- 10 years, 48 males). In all patients, radiofrequency (RF) ablation was performed by means of a nonfluoroscopic navigation system, in order to anatomically create circumferential lines around the PV. In group B, the persistence of PV potentials was ascertained with a multipolar circular catheter. If PV potentials persisted, RF energy targeting the electrophysiological breakthroughs was delivered to disconnect the PV. Past a 2-month period of observation, success was defined as absence of any atrial tachyarrhythmia recurrence lasting >30 seconds. RESULTS: Total procedure duration (220 +/- 62 minutes vs 140 +/- 43 minutes, P < 0.001), fluoroscopy time (35 +/- 15 minutes vs 17 +/- 9 minutes, P < 0.001), and RF delivery time (48 +/- 22 minutes vs 27 +/- 9 minutes, P < 0.001) were significantly longer in group B than in group A. One cardiac perforation occurred in group A. After 15 +/- 9.1 months, 21 patients in group A (58%) and 34 patients in group B (56%) were free of atrial tachyarrhythmia recurrence (P = 0.9). CONCLUSIONS: In patients with persistent AF, who underwent an anatomical approach, electrophysiological confirmation of PV disconnection significantly increased the fluoroscopy and procedural times, without effect on the long-term outcomes.

Long-term outcomes of CRT-PM versus CRT-D recipients.

OBJECTIVE: To compare the rates of all-cause mortality in recipients of cardiac resynchronization therapy devices without (CRT-PM) versus with defibrillator (CRT-D). METHODS: Between February 1999 and July 2004, 233 patients (mean age = 69 +/- 8 years, 180 men) underwent implantation of CRT-PM or CRT-D devices. New York Heart Association (NYHA) heart failure functional class II was present in 11%, class III in 69%, and class IV in 20% of patients; mean left ventricle ejection fraction (LVEF) was 26.5 +/- 6.5 %, 48% presented with idiopathic dilated cardiomyopathy and 49% with ischemic heart disease. Cox multiple variable regression analysis was performed in search of predictors of death. RESULTS: The clinical characteristics of the 117 CRT-PM and 116 CRT-D recipients were similar, except for LVEF (28.2 +/- 6.2% vs 25.0 +/- 6.5%, respectively; P < 0.001), and ischemic versus nonischemic etiology of heart failure (41% vs 56%, respectively P = 0.02). Over a mean follow-up of 58 +/- 15 months, no significance difference in overall mortality rate was observed between the two study groups. Male sex, NYHA functional class IV, and atrial fibrillation at implant were significant predictors of death. CONCLUSIONS: There was no difference in long-term survival rate among patients with CRT-D versus CRT-PM, although CRT-D more effectively lowered the sudden death rate. Male sex, NYHA functional class IV, and atrial fibrillation predicted the worst prognosis.

High prevalence of cooled tip use as compared with 8-mm tip in a multicenter Italian registry on atrial fibrillation ablation: focus on procedural safety.

BACKGROUND: Whether cooling catheters should be preferred for atrial fibrillation (AF) ablation is not yet clear. METHODS: From April 2005 to October 2006, 991 (74% men) consecutive patients who underwent AF ablation were prospectively enrolled in 10 Italian centers. For the present subanalysis, patients were ranked in the two study groups on the basis of the catheter system chosen: 8-mm tip was used in 86 patients (9% conventional group) and open-irrigated tip in 905 patients (91% cooled group). RESULTS: The registry clinical data of both groups showed marked heterogeneity due to the fact that the higher number of patients of the cooled group had longer AF history (4.9+/-4.1 versus 1.2+/-1.8 years; P=0.0001), permanent/persistent AF (41.2 versus 27.9%; P=0.01), and larger left atrium (LA) size (44.1+/-6.2 versus 33.4+/-10.5 mm; P

Radiofrequency circumferential ablation limited to the left atrium showing fibrillatory activity in a patient with paroxysmal atrial fibrillation.

We report a case of a tailored approach to atrial fibrillation based on the substrate. In a patient with paroxysmal atrial fibrillation, electroanatomic mapping showed that atrial fibrillation was limited to a large area around the ostia of right pulmonary veins. The patient was successfully treated by catheter anatomic isolation of this area from the remaining part of the left atrium.

Early complications of pulmonary vein catheter ablation for atrial fibrillation: a multicenter prospective registry on procedural safety.

BACKGROUND: Data on the procedural safety of pulmonary vein radiofrequency catheter ablation for atrial fibrillation (AF) are as yet scant. OBJECTIVE: The aims of the present study were to prospectively evaluate the incidence of early complications of pulmonary vein ablation for AF in an unselected population of consecutive patients, and to identify possible predictors. METHODS: From April 2005 to October 2006, data from 1,011 consecutive patients who were undergoing radiofrequency catheter ablation for every type of AF in 10 Italian centers were collected. All complications occurring from the admission of the patient up to the 30th day were considered. RESULTS: No procedure-related death was observed. Complications occurred in 40 patients (3.9%): 12 (1.2%) had peripheral vascular complications, 8 (0.8%) had conservatively treated pericardial effusion, 6 (0.6%) had cardiac tamponade (successfully drained), 5 (0.5%) had cerebral embolisms, 4 (0.4%) presented pulmonary vein stenosis >50%, and 5 (0.5%) presented other isolated adverse events. History of coronary artery disease (odds ratio 5,603, 95% confidence interval 1,559 to 20,139, P < .008) characterized patients who presented with hemorrhagic complications. CONCLUSION: Early complications of pulmonary vein catheter ablation seem to be fewer than in the early years of AF ablation, but still occur in 3.9% of procedures.

Antiarrhythmic drug therapy after radiofrequency catheter ablation in patients with atrial fibrillation.

OBJECTIVES: The use of antiarrhythmic drugs after ablation is a controversial issue when evaluating the efficacy of atrial fibrillation (AF) ablation. This study compares in a prospective and randomized fashion the impact of an antiarrhythmic drug in preventing AF recurrence after AF ablation. METHODS: From February 2004 to May 2005, 107 consecutive patients (mean age 57 +/- 10 years, 69 men), with paroxysmal (60%) or persistent (40%) drug refractory AF, were randomly assigned to ablation alone (Group A, 53 patients) or combined with the best antiarrhythmic therapy, preferably amiodarone (Group B, 54 patients). All patients underwent cavo-tricuspid and left inferior pulmonary vein (PV)-mitral isthmus ablation plus circumferential PV ablation, using a guided electro-anatomical approach. Standard electrocardiograms (ECG), and ambulatory and transtelephonic ECG monitoring were used to assess AF recurrences. Recurrences during the first month after ablation were excluded from this analysis. RESULTS: At 12 months of follow-up, no significant difference was observed in the rates of AF recurrences between Group A (18/53 patients, 34%) and Group B (16/54 patients, 30%). The percentage of patients with >/= 1 asymptomatic AF episode was higher in Group B than in Group A (10/16 patients, 63%, vs 5/18 patients, 28%, P = 0.04). CONCLUSIONS: Continuing antiarrhythmic drug therapy in patients who undergo catheter ablation for AF did not lower the rate of AF recurrences. Antiarrhythmic drugs increased the proportion of patients with asymptomatic AF episodes.

Long-term performance of coronary sinus leads used for cardiac resynchronization therapy.

BACKGROUND: Little is known regarding the long-term performance of coronary sinus (CS) leads, which have an effect on the longevity of cardiac resynchronization therapy (CRT) systems. METHODS: This study included 109 patients (79 men) whose mean age was 68 +/- 9 years, New York Heart Association (NYHA) functional class 3.2 +/- 0.5, and left ventricular ejection fraction 25.6 +/- 6.6%, and who underwent CRT (n = 45) or CRT-D (n = 64) systems implants for management of idiopathic (53%), ischemic (40%), or miscellaneous (7%) dilated cardiomyopathy. Unipolar (n = 57) or bipolar (n = 52) leads were placed into the CS venous system. RESULTS: At implant, no significant difference was observed between unipolar and bipolar leads with respect to mean sensing performance (14 +/- 6 mV vs 14 +/- 8 mV, P = 0.97), pacing impedance (875 +/- 234 ohms vs 943 +/- 331 ohms, P = 0.24), and stimulation energy threshold (2 +/- 3.2 muJ vs 1.13 +/- 1.5 muJ, P = 0.08). At a median follow-up of 33 months, a significant decrease in stimulation impedance and increase in stimulation energy threshold was observed with unipolar (689 +/- 122 vs 875 +/- 234 ohms, P < 0.01, and 8.34 +/- 10.4 muJ vs 2 +/- 3.2 muJ, P < 0.001, respectively) as well as with bipolar (735 +/- 268 ohms vs 943 +/- 331 ohms, P < 0.01, and 4.81 +/- 9.92 vs 1.13 +/- 1.5 muJ, P = 0.02, respectively) leads. No significant difference in sensing performance was observed with either type of lead (10 +/- 5 mV vs 14 +/- 6 mV and 10 +/- 6 mV vs 14 +/- 8 mV, respectively). At long-term follow-up, no significant difference among any sensing or stimulation parameter was observed between unipolar and bipolar leads. CONCLUSIONS: At long-term follow-up, a significant increase in the energy required for stimulation was observed, whereas sensing performance remained unchanged. The increase in energy capture threshold was less marked with bipolar than with unipolar leads.

Acute left ventricular dyssynchrony improvement predicts long-term benefit from cardiac resynchronization therapy.

STUDY OBJECTIVE: To evaluate the relationship between acute response to cardiac resynchronization therapy (CRT) and long-term clinical outcome in patients with drug refractory heart failure. METHODS AND RESULTS: In 28 patients undergoing CRT implant, left ventricular (LV) dyssynchrony was evaluated by tissue Doppler imaging (TDI)-derived longitudinal strain by mean of septum-lateral basal asynchrony index (S-Li) and basal delayed longitudinal contraction (DLC). TDI measurements were made before, and 30 minutes and 1 year after implant. Baseline and 1-year follow-up New York Heart Association (NYHA) functional class, 6-minute walking test (6-MWT) distance, and quality of life (QoL) score were measured. Responders (n = 22) were defined by a >/= 1 decrease in NYHA functional class and 6-MWT >/= 25% at 1 year. At baseline, no differences were observed between responders and nonresponders in clinical and echocardiographic measurements. LV dyssynchrony acutely recovered only in responders 30 minutes after implantation, with a significant reduction in S-Li and DLC. Moreover, the percent decreases in S-Li and DLC were highly correlated with those observed in NYHA class (r = 0.70, and r = 0.81, respectively, P < 0.001), 6-MWT (r = 0.59, and r = 0.57, respectively, P < 0.001 and P < 0.01), and QoL score (r = 0.71, and r = 0.83, respectively, p < 0.001) at 1-year follow-up. CONCLUSIONS: Acute recovery of LV intraventricular dyssynchrony is a major discriminator between responders and nonresponders to CRT, which strongly correlates with a favorable long-term clinical outcome.

Dynamic and dual-site atrial pacing in the prevention of atrial fibrillation: The STimolazione Atrial DInamica Multisito (STADIM) Study.

OBJECTIVES: The impact of new algorithms to consistently pace the atrium on the prevention of atrial fibrillation (AF) remains unclear. Our randomized, crossover study compared the efficacy of single- and dual-site atrial pacing, with versus without dynamic atrial overdrive pacing in preventing AF. METHODS: We studied 72 patients (mean age = 69.6 +/- 6.5 years, 34 men) with sick sinus syndrome (SSS) and paroxysmal or persistent AF, who received dual-chamber pacemakers (PM) equipped with an AF prevention algorithm and two atrial leads placed in the right atrial appendage (RAA), by passive fixation, and in the coronary sinus ostium (CS), by active fixation, respectively. At implant, the patients were randomly assigned to unipolar CS versus RAA pacing. The PM was programmed in DDDR mode 1 month after implant. Each patient underwent four study phases of equal duration: (1) unipolar, single site (CS or RAA) pacing with the AF algorithm ON (atrial lower rate = 0 ppm); (2) unipolar, single site pacing with the AF algorithm OFF (atrial lower rate = 70 bpm); (3) bipolar, dual-site pacing with AF algorithm ON; (4) bipolar, dual-site pacing with the AF algorithm OFF. RESULTS: Among 40 patients (56%), who completed the follow-up (15 +/- 4 months) no difference was observed in the mean number of automatic mode switch (AMS) corrected for the duration of follow-up, in unipolar (5.6 +/- 22.8 vs 2.6 +/- 5.5) or bipolar mode (3.3 +/- 12.7 vs 2.1 +/- 4.9) with, respectively, the algorithm OFF or ON. With the AF prevention algorithm ON, the percentage of atrial pacing increased significantly from 78.7 +/- 22.1% to 92.4 +/- 4.9% (P < 0.001), while the average ventricular heart rate was significantly lower with the algorithm ON (62.4 +/- 17.5 vs 79.9 +/- 3 bpm (P < 0.001). CONCLUSIONS: The AF prevention algorithm increased the percentage of atrial pacing significantly, regardless of the atrial pulse configuration and pacing site, while maintaining a slower ventricular heart rate. It had no impact on the number of AMS in the unipolar and bipolar modes in patients with SSS.

A clinical and health-economic evaluation of pulmonary vein encircling ablation compared with antiarrhythmic drug treatment in patients with persistent atrial fibrillation (Catheter Ablation for the Cure of Atrial Fibrillation-2 study).

AIMS: Catheter Ablation for the Cure of Atrial Fibrillation 2 study is a prospective, randomized trial aimed to demonstrate the efficacy of catheter ablation with combined lesions in the right and left atria, in preventing atrial fibrillation (AF) recurrences among patients with recurrent persistent AF refractory to one antiarrhythmic drug, in comparison with the best pharmacological therapy. METHODS AND RESULTS: Enrolment is limited to patients aged between 18 and 70 years who have experienced at least one documented relapse of persistent AF during antiarrhythmic drug therapy. One hundred and twenty-six patients will be randomized to ablation or antiarrhythmic drug therapy in a 2 : 1 manner. In the ablation group, the patients will undergo right and left atrial linear ablation. Control group patients will be treated with the best antiarrhythmic drug. After an initial blanking period of 2 months patients will be followed for 24 months. Primary endpoint of the study is the absence of documented persistent atrial tachyarrhythmias relapse during the first 24 months after the blanking period. Enrolment is scheduled in 14 centres in Italy, UK, Austria, and Finland. Seventy-two patients have currently been enrolled. CONCLUSION: This study will provide important data about the efficacy of catheter ablation in comparison with antiarrhythmic drugs for the treatment of persistent AF.

Long-term outcome of right and left atrial radiofrequency ablation in patients with persistent atrial fibrillation.

OBJECTIVES: To investigate the clinical outcome of right and left atrial radiofrequency ablation after the first 12 months in patients with drug-refractory persistent atrial fibrillation (AF), and to identify predictors of long-term success. METHODS: We analyzed the clinical outcome of 74 consecutive patients with a follow-up >12 months who underwent right and left atrial ablation for persistent AF. Patients who did not present symptomatic or asymptomatic atrial tachyarrhythmias (AT) lasting >30 seconds after the first 3 months of follow-up were defined responders to pulmonary veins ablation. RESULTS: After a mean follow-up of 20.2 +/- 6.3 months (12-36), 52/74 (70%) patients were deemed responders. AT relapsed within the first 12 months in 19/74 (26%) patients (17 AF and 2 left atrial flutter). Among those patients who did not relapse within the first 12 months, only 3 patients (5%) presented AF after the first year of follow-up. At the multivariate analysis presence of early AT relapse and history of AF >7 years inversely correlated with a successful long-term clinical outcome. CONCLUSION: Right and left atrial ablation, alone or in association with antiarrhythmic drugs, prevented AT relapses in 70% of patients with drug-refractory persistent AF also after the first 12 months. Presence of AT relapse within the first 3 months and history of AF >7 years identified patients with a lower probability of successful long-term clinical outcome.