P2650Left atrial linear ablation negatively affects atrial function

Abstract

Background: Atrial fibrillation (AF) involves atrial structural and mechanical remodelling characterized by left atrial (LA) enlargement and may cause LA and left ventricular (LV) functional impairment. Thoracoscopic surgery for AF may terminate AF and thereby contribute to reverse remodelling. However, the effects of LA ablation scars on atrial and ventricular reverse remodelling following thoracoscopic surgery for AF, remains unclear. Objective: We performed a subanalysis of the AFACT study and assessed the effects of thoracoscopic surgery for AF on reverse structural and mechanical remodelling of the LA and LV. Methods: The AFACT trial randomised 240 patients with AF to ganglion plexus (GP) ablation or no GP ablation during thoracoscopic pulmonary vein isolation (PVI). Additional ablation lines were constructed in persistent AF patients and consisted of a roof and trigone line. We determined LA and right atrial (RA) volume indexes, LA ejection fraction (EF), cardiac index (CI), E, A and LVEF on transthoracic echocardiograms (TTE) at baseline and six months after surgery. Patients who were in sinusrhythm (SR) during both TTE examinations were included. We stratified patients based on the presence of additional ablation lines. Paired student's t tests were used to compare baseline TTE with follow‐up using a p‐value<0.0013 after Bonferroni correction. Results: We included 119 out of 240 AFACT participants who were in SR during the TTE at baseline and follow‐up (74.8% men; age 59 (IQR 55‐65); 52.1% GP ablation; 39.5% ablation lines). During follow‐up, AF did not recur in 89.1% of patients. GP ablation was not related to a difference at six month's TTE. In all patients, LA volume index remained unchanged (36.9±10ml/m2 vs 37.0±10ml/m2, p=0.876) and E/A ratio significantly increased from 1.41±0.65 to 1.67±0.81 (p<0.001) due to a significant decrease in A from 0.62±0.21cm/s to 0.51±0.18cm/s (p<0.001). After patient stratification to PVI only or PVI with ablation lines, the increase in E/A ratio was only seen in patients with ablation lines due to a distinct decrease of the A wave, which was not as prominent in patients without ablation lines (figure). In patients with ablation lines, LAEF also decreased from 40.8±15% to 34.4±11% (p<0.001). Finally, LVEF decreased in patients without ablated lines from 55.6±7% to 52.2±8% (p=0.0011) while CI was unchanged, likely due to improved mitral valve function. Conclusions: LA volume index remained unchanged after thoracoscopic surgery for AF. Additional ablation lines after thoracoscopic surgery for AF were associated with a decreased A wave and LAEF. LVEF decreased, while CI was unchanged in patients without additional ablation lines. Therefore, potential negative outcome and long‐term hemodynamics of additional linear ablation during thoracoscopic surgery for AF needs further investigation. (Figure Presented).