Introduction: Catheter ablation has been shown to be safe and effective in reducing atrial fibrillation (AF) burden and symptoms. However, there is limited long term data using continuous monitoring to assess the actual success of catheter ablation. This study assessed the long-term outcome of AF ablation in patients with implantable cardiac devices allowing beat-to-beat analysis of arrhythmia outcomes.
Methods: 223 patients (mean age 75.9 ± 7.4, 50.9% men) who underwent catheter or thorascopic surgical ablation for symptomatic AF were studied. The techniques used were PVAC ablation (51.6%), cryoablation (16.1%), point by point (13.0%), nMARQ (12.1%) and surgical ablation (7.2%). All patients had a cardiac implantable device (109 pacemaker and 114 implantable loop recorder), and were followed up for a mean period of 735.2 ± 338.0 days, post ablation.
Results: 146 (65.5%) patients had paroxysmal AF (PAF) and 77 (34.5%) patients had persistent AF. After first ablation there was a significant reduction in AF burden (relative risk 0.91, 95% CI 0.89 to 0.94; P = <0.01). Median AF burden in PAF patients reduced from (interquartile range [IQR], 0.1%-8.08%) to 0.10% ([IQR], 0%-2.44%) at one year and this was maintained up to four-year follow up. In persistent AF patients AF burden reduced from 99.9% ([IQR], 51.53%-100%) to 0.30% ([IQR], 0%-77.25%) at one year however increased to 87.3% ([IQR], 4.25%-100%) at four years follow up (Figure 1). At first ablation there was no significant difference in AF burden reduction between the different techniques used (p=0.32). At second ablation point by point ablation was associated with greater reduction in AF burden (relative risk, 0.77 [95% CI, 0.65–0.91]; P = <0.01).
Conclusion: Ablation results in significant reductions in AF burden both acutely and over the long term when assessed using continuous device derived beat-to-beat monitoring. When second ablation was required the point-by-point technique was associated with greater reductions in AF burden than “single shot” technologies. In persistent AF, burden increased two years after ablation to near pre ablation levels by year 4 suggesting a different mechanism from PAF patients where this increase was not demonstrated.