Long-term results and the predictors of outcome of catheter ablation of atrial fibrillation using steerable sheath catheter navigation after single procedure in 674 patients

Catheter ablation of atrial arrhythmias: state of the art

Catheter ablation is at the forefront of the management of a range of atrial arrhythmias. In this Series paper, we discuss the underlying mechanisms and the current role of catheter ablation for the three most common atrial arrhythmias encountered in clinical practice: focal atrial tachycardia, atrial flutter, and atrial fibrillation. The mechanisms of focal atrial tachycardia and atrial flutter are well understood, and these arrhythmias are amenable to curative catheter ablation with high success rates. In most cases, paroxysmal atrial fibrillation is initiated by triggers located within pulmonary vein musculature. Circumferential ablation to isolate this musculature is associated with high success rates for elimination of paroxysmal atrial fibrillation in selected populations. Because of the problem of recurrent pulmonary vein connection, more than one procedure will be needed in about 30% of patients, and new technologies are being developed to reduce this occurrence. The mechanisms that sustain persistent atrial fibrillation are not well understood and are the subject of continuing investigation. As such, ablation approaches and technologies for this arrhythmia are still evolving.

Colchicine for prevention of early atrial fibrillation recurrence after pulmonary vein isolation: a randomized controlled study

OBJECTIVES

The purpose of the present study was to test the potential of colchicine, an agent with potent anti-inflammatory action, to reduce atrial fibrillation (AF) recurrence after pulmonary vein isolation in patients with paroxysmal AF.

BACKGROUND

Proinflammatory processes induced by AF ablation therapy have been implicated in postablation arrhythmia recurrence.

METHODS

Patients with paroxysmal AF who received radiofrequency ablation treatment were randomized to a 3-month course of colchicine 0.5 mg twice daily or placebo. C-reactive protein (CRP) and interleukin (IL)-6 levels were measured on day 1 and on day 4 of treatment.

RESULTS

In the 3-month follow-up, recurrence of AF was observed in 27 (33.5%) of 80 patients of the placebo group versus 13 (16%) of 81 patients who received colchicine (odds ratio: 0.38, 95% confidence interval: 0.18 to 0.80). Gastrointestinal side-effects were the most common symptom among patients receiving active treatment. Diarrhea was reported in 7 patients in the colchicine group (8.6%) versus 1 in the placebo group (1.3%, p = 0.03). Colchicine led to higher reductions in CRP and IL-6 levels: the median difference of CRP and IL-6 levels between days 4 and 1 was -0.46 mg/l (interquartile range: -0.78 to 0.08 mg/l) and -0.10 mg/l (-0.30 to 0.10 pg/ml), respectively, in the placebo group versus -1.18 mg/l (-2.35 to -0.46 mg/l) and -0.50 pg/ml (-1.15 to -0.10 pg/ml) in the colchicine group (p < 0.01 for both comparisons).

CONCLUSIONS

Colchicine is an effective and safe treatment for prevention of early AF recurrences after pulmonary vein isolation in the absence of antiarrhythmic drug treatment. This effect seems to be associated strongly with a significant decrease in inflammatory mediators, including IL-6 and CRP.

Quantitative Analysis of Isolation Area and Rhythm Outcome in Patients With Paroxysmal Atrial Fibrillation After Circumferential Pulmonary Vein Antrum Isolation Using the Pace-and-Ablate Technique

Background—

We sought to determine the relationship between the size of the left atrial isolated surface area (ISA) after pulmonary vein antrum isolation for paroxysmal atrial fibrillation (AF) and rhythm outcome during a 12-month follow-up.

Methods and Results—

One hundred one consecutive patients with paroxysmal AF (mean age, 59±11 years; median [range] AF history, 36 [24–96] months; mean left atrial size, 42±6 mm) were enrolled. The ISA was defined as the ratio of the total isolated antral surface area excluding the pulmonary veins to the sum of the total isolated antral surface area and the left atrial posterior wall surface area, while considering the individual characteristics of antral anatomy. All surface areas were assessed using the NavX system. Patients were divided into 4 groups according to ISA (group I: <50%; group II: 50 to <60%; group III: 60 to <70%; group IV: ≥70%). The average ISA for all patients was 59.2±11.6%. Subgroup analysis showed that ISA was 42.8±4.2% in group I (n=23), 54.2±3.0% in group II (n=23), 64.3±3.0% in group III (n=33), and 73.9±3.6% in group IV (n=22). After a 12-month follow-up period, 70% of patients in group I, 78% in group II, 97% in group III, and 100% in group IV were free from AF and atrial macroreentrant tachycardia. There was a significant difference between groups I and III, I and IV, II and III, and II and IV but not groups I and II and groups III and IV (log-rank test P =0.024, 0.016, 0.037, 0.044, 0.584, and 0.500, respectively). Receiver operating characteristic curve analysis yielded an optimal cutoff value of 55% for ISA.

Conclusions—

After 12 months, a larger ISA was associated with a significantly lower AF and macroreentrant tachycardia recurrence rate. ISA≥55% may thus serve as a predictor for long-term success after pulmonary vein antrum isolation.

2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design

This is a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation, developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology and the European Cardiac Arrhythmia Society (ECAS), and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). This is endorsed by the governing bodies of the ACC Foundation, the AHA, the ECAS, the EHRA, the STS, the APHRS, and the HRS.

Markers of oxidative stress after ablation of atrial fibrillation are associated with inflammation, delivered radiofrequency energy and early recurrence of atrial fibrillation

BACKGROUND

The role of oxidative stress after radiofrequency ablation of atrial fibrillation (AF) has not yet been well characterized. We sought to evaluate the time course of biomarkers of oxidative stress and inflammation after AF ablation and their association with clinical variables.

METHODS

Thirty consecutive patients (57.9 ± 1.7 years, 63% males) with paroxysmal AF underwent pulmonary vein isolation and ablation of complex fractionated atrial electrograms. Biomarkers were determined in blood samples before ablation and 6 h, 1, 2, 7, 30, 90 and 180 days post-ablation.

RESULTS

The pro-oxidant enzyme myeloperoxidase and oxidized low-density lipoprotein reflecting oxidant damage of lipoproteins increased 2.9 ± 0.2-fold and 1.2 ± 0.1-fold, respectively, and were significantly up-regulated until day 2 post-ablation. The anti-oxidant enzyme copper/zinc superoxide dismutase did not change significantly. Inflammatory markers significantly increased (high-sensitivity C-reactive protein (hs-CRP): 41 ± 8-fold; interleukin-6: 4.4 ± 0.7-fold) for 7 and 2 days, respectively. The increase of myeloperoxidase and hs-CRP was interrelated and both predicted early recurrence of AF within the first post-ablation week (both p < 0.05). The increase of both markers was associated with the amount of delivered radiofrequency energy (p < 0.05). The up-regulation of hs-CRP correlated with troponin T (p = 0.008), while myeloperoxidase and troponin T were borderline associated (p = 0.054). However, the oxidative and inflammatory responses did not predict long-term ablation outcome (p > 0.05).

CONCLUSIONS

Markers of oxidative stress showed a significant up-regulation during the first 2 days after AF ablation. Their up-regulation was linked to inflammation, delivered radiofrequency energy, and early recurrence of AF, but did not predict long-term ablation outcome.

Early recurrence of atrial tachyarrhythmias following radiofrequency catheter ablation of atrial fibrillation

The use of blanking periods, the immediate period postablation during which transient tachyarrhythmia episodes are not considered recurrences, has been predicated on the assumption that not all early recurrences of atrial tachyarrhythmias (ERAT) will lead to later recurrences and, as such, does not necessarily represent treatment failure. While ERAT can be expected to occur in approximately 38% of patients within the first 3 months of atrial fibrillation (AF) ablation, only half of these patients will manifest later recurrences. Clinical features related to the patient's history of AF, the index ablation procedure, and particularities of the ERAT can help identify patients at higher risk of later recurrence in whom aggressive attempts to control rhythm, including early cardioversion and reintervention, may be justified.

Predictors of recurrence in patients undergoing cryoballoon ablation for treatment of atrial fibrillation: the independent role of sleep-disordered breathing

INTRODUCTION

In patients with atrial fibrillation (AF) undergoing pulmonary vein isolation, cryoballoon technique (cryoPVI) has been adopted in many centers. This study aimed to evaluate predictors of AF recurrence including impact of sleep-disordered breathing (SDB).

METHODS AND RESULTS

In 82 patients consecutively assigned to cryoPVI cardiorespiratory screening for SDB, assessment of medical history, ECG, echocardiography, standard laboratory measurement, and blood gas analysis were performed prior to intervention. After a 3-month blanking period, a 7-day Holter ECG was performed at 3, 6 and then every 6 months to determine AF recurrence. Seventy-five patients (69 paroxysmal AF, 6 persistent AF, 22 female, age 60 ± 9 years) completed at least 6-month follow-up. Median follow-up of 12 months (interquartile range 6-18 months) confirmed maintenance of sinus rhythm in 69.4% of these patients. Stepwise forward regression model revealed moderate to severe SDB (cut-off apnea-hypopnea-index (AHI) ≥ 15 per hour; Hazard Ratio (HR) 2.95, P = 0.04), early recurrence of AF (HR 8.74, P < 0.001), persistent AF (HR 7.16, P < 0.001), preprocedural class III-antiarrhythmic drug treatment (HR 3.63, P = 0.02), but not SDB per se (AHI ≥ 5 per hour) as independent predictors for AF recurrence.

CONCLUSION

Moderate to severe SDB is a treatable condition that independently predicts AF recurrence in patients undergoing cryoPVI. Screening for SDB and adequate treatment may improve long-term success of cryoPVI.

Advanced catheter technology: is this the answer to overcoming the long learning curve in complex endovascular procedures

INTRODUCTION

Advanced endovascular procedures require a high degree of skill with a long learning curve. We aimed to identify differential increases in endovascular skill acquisition in novices using conventional (CC), manually steerable (MSC) and robotic endovascular catheters (RC).

MATERIALS/METHODS

10 novices cannulated all vessels within a CT-reconstructed pulsatile-flow arch phantom in the Simulated Endovascular Suite. Subjects were randomly assigned to conventional/manually-steerable/robotic techniques as the first procedure undertaken. The operators repeated the task weekly for 5 weeks. Quantitative (cannulation times, wire/catheter-tip movements, vessel wall hits) and qualitative metrics (validated rating scale (IC3ST)) were compared.

RESULTS

Subjects exhibited statistically significant differences when comparing initial to final performance for total procedure times and catheter-tip movements with all catheter types. Sequential non-parametric comparisons identified learning curve plateau levels at weeks 2 or 3(RCs, MSCs), and at week 4(CCs) for the majority of metrics. There were significantly fewer catheter-tip movements using advanced catheter technology after training (Week 5: CC 74 IQR(59-89) versus MSC 62(44-81); p = 0.028, and RC 33 (28-44); p = 0.012). RCs virtually eliminated wall hits at the arch (CC 29(28-76) versus RC 8(6-9); p = 0.005) and produced significantly higher overall performance scores (p < 0.02).

CONCLUSION

Advanced endovascular catheters, although more intricate, do not seem to take longer to master and in some areas offer clear advantages with regards to positional control, at a faster rate. RCs seem to be the most intuitive and advanced skill acquisition occurs with minimal training. Robotic endovascular technology may have a significantly shorter path to proficiency allowing an increased number of trainees to attempt more complex endovascular procedures earlier and with a greater degree of safety.

Steerable versus nonsteerable sheath technology in atrial fibrillation ablation: a prospective, randomized study

BACKGROUND

Steerable sheath technology is designed to facilitate catheter access, stability, and tissue contact in target sites of atrial fibrillation (AF) catheter ablation. We hypothesized that rhythm control after interventional AF treatment is more successful using a steerable as compared with a nonsteerable sheath access.

METHODS AND RESULTS

One hundred thirty patients with paroxysmal or persistent drug-refractory AF undergoing their first ablation procedure were prospectively included in a randomized fashion in 2 centers. Ablation was performed by 10 operators with different levels of clinical experience. Treatment outcome was measured with serial 7-day Holter ECGs and additional symptom-based arrhythmia documentation. Single procedure success (freedom from AF and/or atrial macroreentrant tachycardia) was significantly higher in patients ablated with a steerable sheath (78% versus 55% after 3 months, P=0.005; 76% versus 53% after 6 months, P=0.008). Rate of pulmonary vein isolation, procedure duration, and radiofrequency application time did not differ significantly, whereas fluoroscopy time was lower in the steerable sheath group (33±14 minutes versus 45±17 minutes, P<0.001). Complication rates showed no significant difference (3.2% versus 5%, P=0.608). On multivariable analysis, steerable sheath usage remained the only powerful predictor for rhythm outcome after 6 months of follow-up (hazard ratio, 2.837 [1.197 to 6.723]).

CONCLUSIONS

AF catheter ablation using a manually controlled, steerable sheath for catheter navigation resulted in a significantly higher clinical success rate, with comparable complication rates and with a reduction in periprocedural fluoroscopy time.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov. Unique identifier: NCT00469638.