Comparison of the point-by-point versus catheter dragging technique for curative radiofrequency ablation of atrial fibrillation

Background: The relationship between the applied techniques and clinical outcomes after radiofrequency (RF) ablation of atrial fibrillation (AF) remains unclear. We compared the results of ablation by RF delivered via a point‐by‐point versus catheter dragging technique for the treatment of AF. Methods: This study included 66 patients with drug‐refractory AF who underwent circumferential pulmonary vein (PV) ablation. A point‐by‐point technique was used in 35 (53%) patients (Group I), and catheter dragging technique in the remaining 31 (47%) patients (Group II). If AF persisted or remained inducible after the PV isolation, additional ablation of complex fractionated atrial electrograms and linear ablation were performed. Results: Significantly, fewer RF applications were delivered in Group II than in Group I. The total RF energy duration delivered was comparable between the two groups (P = 0.55). However, the total energy of RF deliveries was significantly greater in Group II than in Group I (P = 0.02). Despite a longer fluoroscopic exposure time (P = 0.01), the total procedural duration was significantly shorter in Group II than in Group I (P = 0.005). Within 3 months after a single ablation procedure, 24 patients (69%) in Group I versus 13 patients (42%) in Group II had ≥1 recurrence(s) of atrial tachyarrhythmias (P = 0.03). A multivariate analysis showed that a point‐by‐point ablation was the only independent predictor of early atrial tachyarrhythmia recurrences. Conclusions: The catheter dragging technique for ablation of AF was associated with a lower early recurrence rate of atrial tachyarrhythmias than the point‐by‐point technique. (PACE 2011; 15–22)     

Arrhythmia detection after atrial fibrillation ablation: value of incremental monitoring time

Background: After pulmonary vein isolation (PVI), patients need to be followed to analyze the effect of the treatment. We evaluated the influence of the duration of Holter monitoring on the detection of arrhythmia recurrences after a single PVI at 12 months. Methods: Consecutive patients with paroxysmal atrial fibrillation (AF) underwent successful PVI with phased radiofrequency and pulmonary vein ablation catheter. Follow‐up was performed with electrocardiogram at 3, 6, and 12 months and 7‐day Holter at 12 months. Symptomatic patients received additional event recording. The 7‐day Holters at 12 months were evaluated for documented left atrial tachyarrhythmia recurrences, and each individual day with AF was categorized. Results: At 12 months after the procedure, 21 of the 96 (22%) patients had AF on their 7‐day Holter. In the patients with AF recurrence, there was an increase in sensitivity from 53% of a 1‐day Holter up to 88% with 4‐day Holter, and 100% of a 7‐day Holter. Monitoring with duration of less than 4 days resulted in significantly less detection of patients with AF compared to 7‐day Holter. Conclusions: A 4‐day Holter at 12 months has an 88% sensitivity for arrhythmia detection, and appears to provide a sufficient monitoring time. Prolonging the monitoring time to 7 days does not significantly increase the yield. PACE 2012; 35:164–169)     

Catheter ablation for atrial fibrillation: mechanism-based curative treatment

The considerable cumulative morbidity and mortality burden resulting from atrial fibrillation has prompted renewed efforts to seek curative and widely applicable therapies. Currently used drugs are not only frequently ineffective at eliminating fibrillation, but may actually be life threatening. Extensive surgery involving both atria has shown that atrial fibrillation can be eliminated in most, if not all, patients, but at a significant cost. The recent discovery of the pivotal role that myocardial extensions into the pulmonary veins play in the initiation, and probably also the maintenance, of atrial fibrillation, has provided a relatively limited target conducive to catheter-based interventions. In experienced hands, paroxysmal atrial fibrillation can be eliminated in more than 85% of patients by a percutaneous intervention lasting less than 3 h with an attendant nonlethal complication risk of 1 to 2%. Thromboembolic complications and pulmonary vein stenosis are the principal complications that may result from this treatment, but their incidence is decreasing. Success rates in patients with persistent or permanent atrial fibrillation are lower, and it is anticipated that increased understanding of the underlying mechanisms will allow doctors to identify those subsets with the greatest potential for benefit from percutaneous catheter-based interventions. Such progress may allow doctors to extend the benefits of eliminating atrial fibrillation to the widest possible range of patients with this recalcitrant disorder.     

The impact of atrial fibrillation ablation on left atrial function: association with baseline left atrial function

Background: The effect of atrial fibrillation (AF) ablation on left atrial (LA) function has not been sufficiently determined. Methods: We enrolled 115 consecutive patients with paroxysmal or persistent AF that underwent AF ablation. Multidetector computed tomography was performed in sinus rhythm before and 3 months after ablation to evaluate LA volume (LAV) and function. Estimates of maximum and minimum LAV were used to calculate LA emptying fraction (LAEF) ([maximum–minimum LAV]/maximum LAV × 100). Results: AF ablation significantly decreased maximum LAV (59.0 ± 20.4 to 53.3 ± 16.7 cm³, P = 0.001), and maintained LAEF (44.5 ± 13.1% to 43.7 ± 10.9%, P = 0.49). The larger the baseline maximum LAV, the greater the decrease in LAV after ablation, and a smaller baseline LAEF was associated with a larger recovery of LAEF after ablation (regression coefficient =−0.45 and −0.56, respectively, P < 0.0001). Multivariable analyses revealed that an impaired baseline LAEF was an independent predictor of an improvement in LA function (an increase in LAEF of >10%; odds ratio [OR] = 0.88, P < 0.0001), while an older age and preserved baseline LAEF were independently associated with a deterioration of LA function (a decrease in LAEF of >10%; OR = 1.06, P = 0.03; and OR = 1.10, P = 0.0001). Conclusions: AF ablation appears to have a beneficial effect on LA function in patients with impaired LA function at baseline. However, it may reduce LA function in patients with an older age and preserved baseline LAEF. (PACE 2011;1–8)     

Real-time dominant frequency analysis of the pulmonary vein in patients with paroxysmal atrial fibrillation

Background: Paroxysmal atrial fibrillation (PAF) can be treated with pulmonary vein isolation (PVI). A spectral analysis can identify sites of high‐frequency activity during atrial fibrillation (AF). We investigated the role of the PVs on AF perpetuation by dominant frequency (DF) analysis. Methods: Thirty‐one consecutive patients with PAF who underwent PVI were included in the prospective study. DF was calculated in each of the PVs, 16, five, and five sites in the left atrium, the coronary sinus, and the right atrium, respectively. In patients presenting sinus rhythm at the baseline, AF was induced by pacing. The PVs were then divided into two groups; PVs demonstrated the highest DF (HDF‐PV) and others. Results: One patient was excluded from the analysis because sustained AF could not be induced. AF was terminated in 43.3% (13/30) of patients during ablation. Of 92 PVs isolated during AF, 30 and 62 PVs were classified into the HDF‐PV and others, respectively. PAF was more frequently terminated by the HDF‐PV isolation compared to the others (33.3%[10/30] vs 4.8%[3/62], P = 0.0004). Interestingly, nine of the 30 HDF‐PVs showing the highest DF among all 30 regions, including extra PVs, led to AF termination in 88.9% (eight out of nine) of cases. Moreover, the HDF‐PVs isolation resulted in a greater AF cycle length prolongation than the other PVs isolation (12.1±5.0 vs 2.7±7.6 ms, P = 0.007). Conclusion: Termination of PAF was more frequently observed during ablation of the PVs with the highest DF. The PV showing high DF played an important role in the maintenance of PAF. (PACE 2012; 35:28–37)     

Case of catheter ablation of atrial fibrillation in a very young patient without structural heart disease

The patient was an 18‐year‐old man who suffered frequent supraventricular premature complexes (SVPCs) and atrial fibrillation. Catheter ablation was performed, and the left pulmonary vein had been isolated, although firing from within the left inferior pulmonary vein remained. After that, the patient did not exhibit SVPCs and atrial fibrillation.     

Dissociated activity and pulmonary vein fibrillation following functional disconnection: impact for the arrhythmogenesis of focal atrial fibrillation

The present study sought to investigate the electrophysiological properties of isolated pulmonary veins following successful radiofrequency (RF) catheter ablation in patients with paroxysmal atrial fibrillation (PAF). Overall, 71 pulmonary veins in 37 consecutive patients (age: 56 +/- 9 years) with recurrent PAF were targeted for RF ablation at the ostial region in order to achieve a complete functional block. Following disconnection, the incidence of dissociated pulmonary vein (PV) activity and its response to orciprenalin were studied. RF ablation abolished conduction in 67 (94%) of 71 potentially arrhythmogenic PVs after a mean of 10.7 +/- 6.4 RF applications for each PV. After ablation, spontaneous dissociated automatic activity (9 to 52 beats/min, median 27) was found in 6 out of 67 isolated PVs (left superior: n = 1, left inferior: n = 1, right superior: n = 2, common left PV: n = 2). Slight acceleration (13 to 68 beats/min, median 29) of dissociated PV activity was observed during infusion of orciprenalin. Following isolation, initiation of sustained or nonsustained local fibrillation was recorded in only two cases of the common left sided PV with preceding automatic activity. In one patient PV fibrillation occurred during orciprenalin infusion following a repetitive response to a dissociated automatic rhythm with increasing duration as well as destabilization. In the other patient, PV fibrillation occurred immediately after the occurrence of PV automaticity. Slow dissociated automatic rhythms are detectable within 9% of disconnected PVs. The unique anatomic substrate of common left PVs seem to favor the occurrence of local fibrillation following isolation. The initiation pattern of fibrillation within the isolated PV has pathophysiological implications and underlines the contribution of multiple factors to the onset and sustenance of PAF.     

Incremental value of isolating the right inferior pulmonary vein during pulmonary vein isolation procedures in patients with paroxysmal atrial fibrillation

Electrical isolation of the left superior, left inferior, and right superior pulmonary veins (PVs) is often, but not always, effective in eliminating paroxysmal atrial fibrillation (PAF). The incremental clinical value of also isolating the right inferior PV has not been well defined. PV isolation by ostial applications of radiofrequency energy guided by PV potentials was performed in 176 consecutive patients (mean age 52 +/- 11 years) with PAF. The left superior, left inferior, and right superior PVs were targeted in 106 patients, and all four PVs were targeted 70 patients. Successful isolation was achieved in 96% of targeted PVs. The mean duration of follow-up was 15 +/- 7 months. At 1-year follow-up, 58% of patients in whom three PVs were isolated were free of recurrent PAF in the absence of antiarrhythmic drug therapy, compared to 73% of patients in whom all four PVs were isolated (P = 0.07). There is a trend towards a better outcome when all four PVs are isolated than when only the three major PVs are isolated. Whenever feasible, the right inferior PV should be isolated along with the other three PVs during the first ablation procedure in patients with PAF.     

Transvenous catheter cryoablation for treatment of atrial fibrillation: results of a feasibility study

Pulmonary vein (PV) isolation using radiofrequency (RF) ablation can induce PV stenosis. Cryoablation may offer a safer alternative energy source for PV isolation. PV isolation with cryoablation was attempted in 31 patients with paroxysmal atrial fibrillation (AF). Event monitors were used to measure the AF episode burden. Serial spiral CT scans were obtained to monitor PV stenosis pre- and postcryoablation. Cryoablation was immediately successful for PV isolation in 29 of 31 patients (94%), with 5.9 +/- 1.2 months of follow-up. Additional RF ablation was performed for AF recurrences in seven patients. The remaining 22 patients with a single cryoablation procedure demonstrated a time-dependent, long-term reduction in the frequency of AF episodes. At 6 months of follow-up, 18 of 22 of cryo-treated only patients (82%) were free of symptomatic AF episodes, and antiarrhythmic drugs were discontinued in 12 of 22 patients. Serial spiral CT scans demonstrated no change in the cryo-treated PV ostial diameter. PV cryoablation was effective to control paroxysmal AF in most patients. Early recurrences of AF postcryoablation were common, though tended to resolve within 6 months postablation, consistent with a process of reverse atrial remodeling. Cryoablation of the PVs did not cause PV stenosis or other serious adverse events.     

Termination of persistent atrial fibrillation resistant to cardioversion by a single radiofrequency application

This report describes the termination of persistent AF refractory to multiple cardioversions and antiarrhythmic therapy in a patient without structural heart disease, with a single radiofrequency application delivered in the left upper pulmonary vein. The observations and failure of repeated internal and external cardioversion suggest a rapidly firing arrhythmia focus sustaining atrial fibrillation amenable to curative pulmonary vein ablation.     

Pulmonary vein stenosis and remodeling after electrical isolation for treatment of atrial fibrillation: short- and medium-term follow-up

Asymptomatic pulmonary vein (PV) stenosis after PV electrical isolation for atrial fibrillation has been reported in several studies and may be due to dynamic factors. The purpose of this study was to determine if PV stenosis progresses after the initial procedure. Consecutive patients (n = 26) requiring repeat procedures for atrial fibrillation recurrence were studied (mean age 55 +/- 12 years). Segmental PV potential-guided ostial ablation was performed with transvenous catheters. Biplane angiographic images were obtained before and after each procedure (52 procedures). Stenoses were found in 14 (16%) of 87 targeted veins immediately after the initial procedures. After 129 +/- 94 days no new stenoses were found at the second procedure. PV stenoses were unchanged in 8 previously stenosed veins, slightly deteriorated in 1 vein, improved in 2 veins, and fully resolved in 3 veins. No patients had symptoms attributable to PV stenosis. PV stenosis occurred in 6 (9%) of 68 additional veins at the second procedure. No baseline or procedural characteristics predicted stenosis. Progression of PV stenosis is uncommon in the medium term. Complete or partial resolution of PV stenosis occurs in approximately one third of cases. Absence of PV stenosis after an initial procedure does not ensure PV stenosis will not occur with further ablation in the same vein.     

Role of Pulmonary Veins Isolation in Persistent Atrial Fibrillation Ablation:

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.     

Impact of the Preprocedural Frequency of Paroxysmal Atrial Fibrillation on the Clinical Outcome after Catheter Ablation

Background: Pulmonary vein antral isolation (PVAI) is a recommended treatment for symptomatic drug‐refractory paroxysmal atrial fibrillation (PAF). PAF naturally progresses toward persistent AF with an increase in the frequency and duration of AF. The objective of this study was to evaluate whether the preprocedural AF frequency had an impact on the AF recurrence after PVAI in patients with symptomatic PAF. Methods and Results: A total of 362 consecutive patients (61.0 ± 9.8 years; 274 males) with drug‐refractory PAF who underwent PVAI were included. The preprocedural frequency of PAF was daily, weekly, monthly, and yearly in 145 (40.1%), 112 (30.9%), 90 (24.9%), and 15 (4.1%) patients, respectively. There were no significant differences in any of the preprocedural variables between the four groups, except for the number of ineffective antiarrhythmic drugs (AADs). PVAI was successfully performed in all patients. At 12 months after the initial procedure, 63.5% of the entire group of patients were free of AF recurrences without any AADs, respectively. A Cox regression multivariate analysis of the variables including the AF frequency, age, gender, duration of AF, presence of hypertension or structural heart disease, left atrial size, left ventricular ejection fraction, and body mass index demonstrated that the AF frequency was not an independent predictor of AF recurrence after a single ablation procedure (P = 0.194). Conclusions: This study demonstrated that the preprocedural AF frequency did not predict AF recurrence after PVAI in patients with PAF. From the clinical point of view, an additional AF classification based on the preprocedural AF frequency might not be valuable in patients undergoing PVAI. (PACE 2012; 35:1236–1241)     

Widely-split double potentials at the pulmonary vein ostium in patients with atrial fibrillation

Left atrial muscle sleeves extending over the pulmonary veins are critical to the initiation of atrial fibrillation (AF) in some patients. This report describes two patients with paroxysmal AF who demonstrate widely-split pulmonary vein (PV) double potentials at the pulmonary vein ostium during sinus rhythm. The response by the double potentials to PV isolation is also characterized. These cases emphasize the importance of recognizing unusual PV electrophysiology and using patient- and mechanism-specific approaches to catheter ablation for AF.     

Increased NT-pro-B-type natriuretic peptide independently predicts outcome following catheter ablation of atrial fibrillation

Abstract

Aims: To investigate whether NT-proBNP before ablation treatment and after exercise testing has predictive information regarding the clinical outcome following pulmonary vein isolation in patients with atrial fibrillation (AF). Methods: NT-proBNP analysis were obtained before the ablation (before and after exercise test), and repeated at 1, 3, and 12 months after the final procedure. Results: A total of 51 patients were included. At study entry, the median NT-proBNP concentration was 14.0 pmol/L (quartiles: 8.0 and 27.0). After the exercise test, the mean NT-proBNP value increased from 13.0 pmol/L (quartiles: 7.5 and 26.0) to 15.0 pmol/L (quartiles: 9.0 and 34.0), p < 0.001. Following a maximum of two ablations, 22 patients were free of AF while 29 patients experienced recurrent AF. In patients with successful ablation, the mean NT-proBNP concentration at baseline was 10.0 pmol/L (quartiles: 7.0 and 22.2) compared to 22.0 pmol/L (quartiles: 12.0 and 34.5) in patients with ablation failure, p = 0.02. With respect to exercise testing, a trend towards a higher increases during exercise were seen in patients with recurrent AF compared to patients without: 2.0 pmol/L (quartiles 1.9 and 7.0) vs. 1.5 pmol/L (quartiles 0 and 3.0), p = 0.07. A baseline NT-proBNP concentration >15.0 pmol/L was found to be an independent predictor of ablation failure. Conclusion: A significantly lower NT-proBNP concentration at baseline and a trend towards a diminished increase during exercise was seen in patients successfully ablated for AF compared to patients with recurrent AF. A baseline NT-proBNP concentration ≤15 pmol/l independently predicts ablation success.