Associations between stroke risk factors and left atrial low-voltage areas in patients with atrial fibrillation undergoing catheter ablation from the REAL-AF registry
Authors: Nguyen A , Pulaski M , Thorne C , Nauffal V , Osorio J , Singleton M J , Zadeh A , Zei P , Ho I , Rajendra A , Mareddy C , Lee K , Metzl M , Zaman J A B 
Published: May 2024

Abstract

Background
Prior research indicates that increased left atrial low-voltage areas (LA LVA) are linked to comorbidities and CHA2DS2-VASc score in patients with persistent atrial fibrillation (PerAF) undergoing catheter ablation. However, given the heterogeneity of AF where patients may transition between paroxysmal AF (PAF) and PerAF types, it is biologically plausible that these associations span all forms of AF.

Purpose
To investigate the relationship of stroke demographics and comorbidities to LA LVA and AF type in a multicenter registry of patients undergoing catheter ablation.

Methods
The Real-world Experience of Catheter Ablation for the Treatment of Symptomatic PAF and PerAF Using Novel Contact Force Technologies registry (REAL-AF) is a prospective, observational multicenter registry of patients undergoing catheter ablation. We evaluated 6053 patients undergoing first-time catheter ablation for both PAF and PerAF to identify associations between stroke risk factors and LA LVA. LA LVA was determined in contact maps as bipolar voltage &lt;0.50 mV. Mapping was completed using 5-spline high-density catheters before ablation. LA LVA was categorized into low (&lt;5%) vs. high (≥5%) based on preliminary data. Analyses were conducted using independent samples t-test and Chi-square test.

Results
LA LVA was associated with greater CHA2DS2-VASc score (3.2 vs. 2.5, p &lt;0.001). Age 75+ (Odds ratio (OR): 2.22, p&lt;0.001), congestive heart failure (CHF) (OR: 2.01, p&lt;0.001), female sex (OR): 1.51, p&lt;0.001), vascular disease (OR: 1.50, p&lt;0.001), age 65-74 (OR: 1.20, p=0.001), hypertension (OR: 1.38, p&lt;0.001), history of stroke (OR: 1.29, p=0.004) and diabetes (OR: 1.25, p=0.001) were also associated with LA LVA (Table 1). These associations remained significant among a subgroup of those presenting in normal sinus rhythm (N = 3546). Patients with CHF (OR: 2.09, p&lt;0.001), hypertension (OR: 1.89, p&lt;0.001) and male sex (OR: 0.60, p&lt;0.001) were more likely to have PerAF in the LVA ≥5% subgroup (n=1594) (Table 2). All other components of the CHA2DS2-VASc score were not significantly associated with AF type in this subgroup. While there was a significant association between AF type and CHA2DS2-VASc score (PAF: 3.15, PerAF: 3.42, p&lt;0.001) in the LA LVA ≥5% subgroup, the effect size was small (Cohen’s d = -0.179).

Conclusion
LA LVA ≥5% was associated with all separate components and overall CHA2DS2-VASc score. In patients with LA LVA ≥5%, there were only associations between PerAF and CHF, hypertension, and male sex, implying a special role in substrate progression. Our findings suggest that LA LVA may represent a more sensitive clinical phenotyping tool of AF rather than current duration-based ones. This is the largest study to our knowledge in elucidating the relationship between increased LA LVA and stroke risk factors in the AF population.