Abstract 4146618: Differential Impact of Left Atrial Volume on Post-Ablation Recurrence Rates in Patients with Normal and Reduced Left Atrial Ejection Fraction: A DECAAF II Subanalysis

Background: The left atrial volume (LAV) has been known to be positively correlated with the atrial fibrillation (AF) recurrence rates after catheter ablation (CA) but negatively correlated with the left ventricular ejection fraction (LVEF). We hypothesized that LAV plays different roles for patients with normal LVEF (LVEF ≥ 50%) and those with lower LVEF (LVEF < 50%). Method: Out of 843 patients from the DECAAF II trial, 674 patients with baseline LAV and LVEF data were included. Among these, 506 patients were characterized as having normal LVEF, while 168 patients had lower LVEF. For each group, the effect of LAV was studied against the AF recurrence through the Cox model, adjusting for age, sex, baseline LA fibrosis, and comorbidities, including coronary artery disease (CAD), hypertension (HTN), congestive heart failure (CHF), diabetes (DM), and hyperlipidemia (HLD). Patients were further divided into high and low LAV groups and compared performance after CA through the Kaplan-Meier curves and log-rank tests. Result: From Cox models, in the high LVEF group, LAV was identified as a significant predictor of the AF recurrence, with a hazard ratio (HR) of 1.009 (95% CI: 1.006-1.013, p < 0.001) for each unit of increase (Table 1a). In the low LVEF group, LAV was not associated with AF recurrence (Table 1b). As in Figure 1, among lower LVEF patients, high LAV and low LAV provide similar AF recurrence rates. However, low LAV patients with normal LVEF have the lowest AF recurrence rate, while high LAV and normal LVEF patients have the highest AF recurrence rates after CA (p < 0.001). Conclusion: The study found that baseline left atrial volume (LAV) is a strong predictor of AF recurrence after CA for patients with normal LVEF but not for patients with lower LVEF. Patients with large LAV and normal LVEF have even worse outcomes compared to those with large LAV and lower LVEF.