Prognostic implication of left atrial strain in patients experiencing early recurrence of atrial fibrillation after totally thoracoscopic ablation

Background: Although early atrial fibrillation (AF) events during the blanking period after AF ablation are risk factors for late recurrence, data on predictors of late recurrence in patients who experience early AF events are limited. In this study, we investigated the implications of left atrial (LA) strain with respect to long-term outcomes in patients experiencing early AF during the blanking period after totally thoracoscopic ablation (TTA). Methods: A total of 128 patients who underwent TTA between 2012 and 2015 were enrolled from a tertiary center. Peak longitudinal LA strain was measured preoperatively. Early recurrence (ER) was defined as any AF within the 3-month blanking period after TTA. The primary outcome was late recurrence of AF for 5 years, detected on 12-lead electrocardiogram or 24-hour Holter monitoring, excluding the blanking period. Results: Out of 128 patients, 42 (32.8%) experienced ER during the blanking period. Patients who experienced ER had a significantly higher risk of 5-year AF recurrence compared with those who did not [72.7% vs. 29.6%, hazard ratio (HR) =3.69, 95% confidence interval (CI): 2.14-6.36, P<0.001]. Within the group of 42 patients experiencing ER, LA strain with a best cutoff value of 18.6% was the only independent predictor of 5-year AF recurrence (adjusted HR =4.20, 95% CI: 1.08-16.29, P=0.038). Patients with ER and LA strain >18.6% had a risk of 5-year AF recurrence, similar to those without ER (35.2% vs. 29.6%, HR =1.21, 95% CI: 0.36-4.04, P=0.755). Patients with ER and LA strain <18.6% had a significantly higher risk of 5-year AF recurrence compared to those without ER (83.0% vs. 29.6%, HR =4.83, 95% CI: 2.75-8.48, P<0.01). Conclusions: Early AF during the blanking period is common in patients undergoing TTA. In patients with ER, LA strain was an independent predictor of long-term AF recurrence.