Localization of Non-Pulmonary Vein Trigger of Atrial Fibrillation in Relation to Atrial Low Voltage Area

We previously reported that non-pulmonary vein (PV) triggers of atrial fibrillation (AF) often arise from low-voltage areas (LVAs) in the left atrium (LA). However, the specific spatial relationship between trigger sites and distribution of LVAs has not been fully elucidated. This study aimed to analyze the relationship on a site-specific basis.

Out of 1428 patients with AF undergoing catheter ablation, 187 (13.1%) who tested positive for non-PV triggers were enrolled. The spatial relationship between each trigger site and left atrial LVAs was evaluated. The study population included 121 men (66%), 110 patients with non-paroxysmal AF (59%), and 93 undergoing re-do sessions (50%). Mean age, eGFR, BNP, BMI, LAD, and LVEF were 68 ± 11 years, 59.9 ± 18.5 mL/min/1.73m², 116.6 ± 281.4 pg/mL, 23.3 ± 3.6 kg/m², 41.7 ± 6.5 mm, and 59 ± 7.8%, respectively. Non-PV trigger sites could not be identified in 18 cases due to lack of reproducibility. In the remaining 169 cases, single non-PV triggers were identified in 140 cases (82.8%), while 29 cases (17.2%) exhibited multiple triggers. Of the 99 LA non-PV triggers evaluated, 61 (61.6%) originated within an LVA. Half of the remaining non-PV triggers from intact areas were from the vicinity of LVAs. Specifically, more than half of the posterior/septal/inferior triggers arose from LVAs, whereas all anterior/roof triggers originated from LVAs. Patients were categorized into six groups based on trigger location: thoracic vein (superior vena cava, coronary sinus, and patent left superior vena cava), right atrium (RA), septum, LA, multiple triggers, and unidentified triggers. At the 24-month follow-up, the atrial tachyarrhythmia-free rate was significantly lower in the unidentified and multiple trigger groups (p < 0.05).

LA non-PV triggers are closely associated with LVAs, particularly in the LA roof and anterior walls, though this association is less consistent in the posterior, septal, and inferior walls. Voltage mapping patterns may facilitate localization and detection of non-PV trigger sites in the LA.