Morphology-based ECG criteria for identifying left-atrial low-voltage areas on voltage mapping: a diagnostic accuracy study.

BACKGROUND: Left atrial (LA) fibrosis contributes to atrial fibrillation (AF) recurrence beyond pulmonary vein triggers, yet its non-invasive identification pre-ablation remains challenging. While invasive voltage mapping may identify low-voltage areas (LVAs) as a surrogate of atrial substrate abnormality, it is impractical for systematic screening. OBJECTIVE: This single-center retrospective pilot study evaluated the diagnostic performance of predefined ECG morphological criteria for detecting LVAs. METHODS: LVAs were used as a surrogate marker for atrial fibrosis and defined as bipolar voltage of <0.50 mV on invasive mapping in sinus rhythm or CS pacing. Four ECG criteria were evaluated: (1) history of atypical atrial flutter, (2) negative atrial vector attenuation in V1, (3) presence of typical or atypical advanced interatrial block (types I-IV), and (4) poor terminal P-wave progression in V4-V6. The presence of at least one of these criteria was considered indicative of LVAs. Diagnostic performance of the ECG criteria was assessed against invasive voltage mapping as the reference standard. Five electrophysiologists independently analyzed 12-lead ECGs (100 mm/s, 40 mm/mV) from 78 patients undergoing first-time AF ablation. RESULTS: LVAs were present in 35 patients. The predefined ECG-based criteria demonstrated sensitivity 85.7% (95% CI: 70.6-93.7), specificity 95.4% (95% CI: 84.5-98.7), positive predictive value 93.8% (95% CI: 79.9-98.3), and negative predictive value 89.1% (95% CI: 77.0-95.3), with an overall diagnostic accuracy of 91.0% (95% CI: 82.6-95.6) and an AUC of 0.905 (95% CI: 0.838-0.972). Interatrial block and poor terminal P-wave progression were the most frequent predictors. CONCLUSIONS: This proof-of-concept study demonstrated promising diagnostic performance for morphological ECG-criteria in detecting left-atrial LVAs. The proposed four-criteria model correlated strongly with invasive voltage mapping and may represent a promising candidate for further validation as a non-invasive tool for pre-procedural identification of atrial substrate.