Clinical risk scores and left atrial low voltage areas in atrial fibrillation

Introduction

Left atrial low voltage areas (LVAs) represent advanced atrial substrate remodeling and are associated with poor outcomes following atrial fibrillation (AF) ablation. Understanding the relationship between established risk scores and LVAs could improve patient selection and treatment strategies.

Purpose

To evaluate and compare the performance of four clinical risk scores (PALAH, DR-FLASH, APPLE, and CHA2DS2-VASc) in predicting the extent of left atrial LVAs in patients undergoing catheter ablation for AF.

Methods

104 consecutive patients who underwent PVI were included in this study. A sequential high-density 3D bipolar voltage map was constructed in all patients during sinus rhythm (SR), guided by a 3D electroanatomic mapping system. The cutoff value for LVA was defined as a bipolar voltage ≤ 0.5 mV measured in SR. LVA as percentage of the mapped left atrial surface in SR was also calculated.

A novel LVA prediction score, the P.A.L.A.H. risk score, was established.

It includes P wave duration (PWD) on an electrocardiogram (PWD>120ms -1pt), Age (age >65 y/o-1pt, age>75y/o-2 pts), Left atrial diameter (LAD) (LAD>40mm-1pt), Arterial Hypertension (Arterial Hypertension- 1pt), Heart Failure (HF) (HF-2pt). Patients in the study were categorized into five distinct groups based on their P.A.L.A.H. score, which ranged from 0 to 5. Additionally, established risk scores including DR-FLASH, APPLE, and CHA2DS2-VASc were calculated for all patients. Pearson correlation analysis was performed to assess the relationship between each risk score and LVA percentage, as well

as inter-score correlations.

Results

All four risk scores demonstrated statistically significant but modest positive correlations with LVA percentage (Figure 1). DR-FLASH showed the strongest correlation with LVA (r=0.43,p=0.0019), followed by CHA2DS2-VASc (r=0.39, p=0.0038), APPLE (r=0.38, p=0.0066), and PALAH (r=0.33, p=0.0176). The correlation matrix analysis (Figure 2) revealed moderate to strong positive correlations among all risk scores (r=0.56-0.80). DR-FLASH and CHA2DS2- VASc showed the highest inter-score correlation (r=0.80), followed by PALAH-CHA2DS2- VASc (r=0.78), DR-FLASH-APPLE (r=0.72), PALAH-APPLE (r=0.70), and DR-FLASH- PALAH (r=0.67). PALAH demonstrated the lowest correlation with APPLE (r=0.56),suggesting it may capture partially distinct risk factors. Despite these correlations, no single score demonstrated strong predictive ability for LVA extent (all r<0.45).

Conclusions

While all evaluated risk scores showed significant correlations with left atrial low voltage areas, the modest strength of these associations (r<0.45) indicates that atrial substrate remodeling is influenced by factors not fully captured by any single scoring system. These findings highlight the need for dedicated substrate-specific prediction models to better identify patients with advanced atrial remodeling prior to ablation procedures.Correlation between risk scores and LVARelationship among scores and LVA