What question did this study set out to answer?

To evaluate the effectiveness of the STABLE-SR ablation strategy for nonparoxysmal atrial fibrillation compared to conventional techniques.

November 1, 2017Open Access

STABLE-SR (Electrophysiological Substrate Ablation in the Left Atrium During Sinus Rhythm) for the Treatment of Nonparoxysmal Atrial Fibrillation

Key Result

STABLE-SR achieved 74.0% freedom from atrial tachyarrhythmias at 18 months with significantly less procedure time than the STEPWISE group (186.8 vs. 210.5 min, P <0.001).

Key Points

To evaluate the effectiveness of the STABLE-SR ablation strategy for nonparoxysmal atrial fibrillation compared to conventional techniques.
229 symptomatic nonparoxysmal AF patients were randomized to STABLE-SR or STEPWISE groups.
In the STABLE-SR group, CPVI was followed by cavotricuspid isthmus ablation and advanced mapping.
Low-voltage areas were targeted for modification, while additional linear lesions were performed in the STEPWISE group.
Primary endpoint assessed was freedom from atrial tachyarrhythmias after 18 months.
74.0% in the STABLE-SR group achieved success, compared to 71.5% in the STEPWISE group.
STABLE-SR group required significantly less procedure time (186.8 minutes vs. 210.5 minutes).
Reduced post-CPVI fluoroscopic time was noted in STABLE-SR group (11.0 minutes vs. 13.7 minutes).
Energy delivery time was also shorter in the STABLE-SR group (60.1 minutes vs. 75.0 minutes).

Structured PICO

Does the STABLE-SR ablation strategy improve freedom from atrial tachyarrhythmias compared to a conventional STEPWISE approach in patients with nonparoxysmal atrial fibrillation?

Population

229 symptomatic nonparoxysmal atrial fibrillation (NPAF) patients (refractory to ≥1 antiarrhythmic drug, aged 18-80, first-time ablation, persistent or long-lasting AF <3 years), multinational (4 countries).

Intervention

STABLE-SR strategy: Circumferential pulmonary vein isolation (CPVI) + cavotricuspid isthmus ablation + cardioversion to sinus rhythm, followed by left atrial high-density mapping. Areas with low-voltage and complex electrograms were homogenized and eliminated, respectively, with dechanneling if necessary.

Comparator

Conventional STEPWISE strategy: CPVI followed by additional linear lesions (roof, mitral isthmus, CTI) and defragmentation (complex fractionated electrogram ablation) during atrial fibrillation.

Outcome

Freedom from documented atrial tachyarrhythmias for ≥30 s after a single ablation procedure without antiarrhythmic medications at 18 months.

Substrate modification during sinus rhythm (STABLE-SR) achieved similar efficacy to the conventional STEPWISE approach for nonparoxysmal AF but significantly reduced procedure and radiofrequency delivery times.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Background: Circumferential pulmonary vein isolation (CPVI) alone or combined with adjuvant substrate modifications is unsatisfactory for atrial fibrillation (AF) control in nonparoxysmal AF patients. Ablation targeting the fibrotic areas after CPVI (STABLE-SR Electrophysiological Substrate Ablation in the Left Atrium During Sinus Rhythm) is a newly evolved substrate modification strategy. Methods and Results: In this multicenter, randomized clinical trial, 229 symptomatic nonparoxysmal AF patients were 1:1 randomized to STABLE-SR group (n=114) or conventional STEPWISE group (n=115). In the STABLE-SR group, after CPVI, cavotricuspid isthmus ablation and cardioversion to sinus rhythm, left atrial high-density mapping was performed. Areas with low-voltage and complex electrogram were further homogenized and eliminated, respectively. Dechanneling would be done if necessary. In the STEPWISE group, additional linear lesions and defragmentation were performed.The primary end point was freedom from documented atrial tachyarrhythmias for ≥30 s after a single ablation procedure without antiarrhythmic medications at 18 months. At 18 months, 74.0% of the patients in the STABLE-SR group and 71.5% in the STEPWISE group (hazard ratio, 0.78; 95% confidence interval, 0.47–1.29; P =0.325) achieved success according to intention-to-treat analysis. However, less procedure time (186.8±52.7 versus 210.5±48.0 minutes, P <0.001), reduced post-CPVI fluoroscopic time (11.0±7.8 versus 13.7±8.9 minutes, P =0.006), and shorter energy delivery time (60.1±25.1 versus 75.0±24.3 minutes, P <0.001) were observed in the STABLE-SR group compared with the STEPWISE group. Conclusions: STABLE-SR is a simplified, personalized, and effective ablation strategy in nonparoxysmal AF patients. More importantly, over 50% nonparoxysmal AF patients do not need further ablation beyond CPVI and therefore can avoid excessive ablation. Clinical Trial Registration: URL: http://www.clinicaltrials.gov . Unique identifier: NCT01761188.

Bookmark

View Full Paper