A call for shorter blanking period, time to get off the ground

This letter to the editor refers to “The blanking period after atrial fibrillation ablation: an European Heart Rhythm Association survey on contemporary definition and management.” by Stefano Bordignon et al. https://doi.org/10.1093/europace/euac131 and the response to this letter ‘Don’t lose the ground: the EHRA blanking period survey’, by S. Bordignon et al., https://doi.org/10.1093/europace/euac287.

Bordignon et al.¹ are to be congratulated for conducting this survey. Indeed, blanking period (BP) is a debated topic, and this well-structured study featuring a representative sample of experienced electrophysiologists underscores both the clinical significance and the understandable management uncertainties regarding early recurrence (ER).

We would like to stress that the vast majority of the respondents considering ER predictive of late recurrence (LR), are in agreement with the recently published meta-analyses, showing that irrespective of ablation modality and atrial fibrillation (AF) type, ER is independently associated with LR.^2,3 Calkins et al.² suggested that 90% of patients not encountering ER post-radiofrequency ablation remain arrhythmia free, and Vrachatis et al.³ found that ER is predictive of arrhythmia recurrence after cryoablation (odds ratio: 5.31; 95% confidence interval: 3.75–7.51).

Evidently, post-ablation anti-arrhythmic drug protocol, monitoring protocol, and persistent AF ablation strategy are highly variable in this survey, which is a reasonable finding in view of no established guidelines. In the meta-analysis conducted by our group, we also observed that varying post-ablation anti-arrhythmic drug protocol was a significant source of statistical heterogeneity, yet the association between ER and LR remained robust in all sub-group analyses.³

Although, most electrophysiologists reckon that half of patients with ER will ultimately suffer LR and 25% already employ a shorter BP for paroxysmal AF, only 1% utilizes an implantable loop recorder to detect asymptomatic ER and 30% opt for no screening at all.¹ We also reported that asymptomatic ER detection is low after cryoablation (6/27 included studies in our meta-analysis) and ER is rarely addressed as a primary endpoint (11/27 studies).³

Taking all together, the timing of ER, rather than energy source or inflammation, seems to be of clinical importance in predicting LR and a call for shortening the BP is around the corner.³ This approach will definitely increase the number of patients necessitating an individualized ‘early’ treatment. Redo-ablation could be a promising option especially for paroxysmal AF, high AF burden during the BP, ER after the first half of the BP and ER presenting as atrial tachyarrhythmia.³ Importantly, the implicated pathophysiologic mechanism of ER should be the epicentre of the decision making process and both cardiac magnetic resonance imaging (cMRI) and artificial intelligence (AI) might be proven pivotal in dealing with ER. Beyond the possibility of extra-pulmonary vein foci, pulmonary vein reconnection (PVR) is implicated in ER cases and cMRI was recently proven effective in ruling out PVR three months post-ablation.⁴ It is also known that ablation lines are fully maturated before 90 days after radiofrequency ablation³ and cMRI datasets have been utilized in a proof-of-concept study showing that AI can assist in a patient specific ablation strategy selection.⁵

Since electrophysiologists are aware of ER clinical implications, future randomized studies should incorporate novel imaging and AI modalities in order to assess the safety, efficacy and cost-effectiveness of early re-intervention (vs. watchful waiting or anti-arrhythmic drugs), as well as the optimal ablation strategy. Treating ER is a new era of uncertainty and it is about time to get off the ground.