Left atrial function of patients with atrial fibrillation undergoing thoracoscopic hybrid ablation.

OBJECTIVES: Thoracoscopic hybrid ablation is an effective and safe rhythm control strategy for patients with complex forms of atrial fibrillation. Its effect on the left atrial function has not yet been studied.

METHODS: In a retrospective single-center analysis of patients undergoing thoracoscopic hybrid ablation, the left atrial emptying fraction was calculated using the biplane modified Simpson method in the apical 2- and 4-chamber views on transthoracic echocardiography. Left atrial strain (reservoir, conduction and contractility) was quantified using dedicated software.

RESULTS: Sixty-seven patients were included (mean age 64 years, longstanding-persistent atrial fibrillation in 69%, median atrial fibrillation history duration 64 months). At baseline, left atrial function and contractility were poor. The reservoir and contractile strain improved post-procedure compared to baseline (15 (SD: 8) and 17 (SD: 6) P=0.013; 3 (SD: 5) and 4 (SD: 4) P=0.008), while left atrial volume indexed to body surface area reduced (51ml/m2 (SD: 14) and 47ml/m2 (SD: 18) P=0.0024). In patients with pre-operative (longstanding)-persistent atrial fibrillation, and in patients with rhythm restoration, an improvement in the emptying fraction, (reservoir and contractile) strain and the left ventricular ejection fraction was observed, while the left atrial volume decreased (P<0.05).

CONCLUSIONS: In this cohort of patients with severely diseased left atria, the improvement in left atrial contractility and emptying fraction after thoracoscopic hybrid ablation for atrial fibrillation in patients with persistent atrial fibrillation is mainly due to rhythm restoration. Interestingly, the procedure itself also results in improved left atrial reservoir strain and reversed left atrial remodeling by reducing left atrial volume.