Patients with smaller LAA remnants after surgical amputation experience greater transient reductions in blood pressure (BP). These findings from the MARK AF registry, presented at the European Society of Cardiology Congress 2025 (ESC 2025), suggest that atrial distension and neurohumoral modulation may play a role in postoperative hemodynamic changes.

This study included 33 adults with persistent atrial fibrillation (AF) who underwent LAA amputation during thoracoscopic AF ablation. Complete amputation was defined as an LAA remnant depth <10 mm, and a remnant as ≥10 mm. Systolic BP was recorded at baseline, 12, 24, and 48 hours, 1 month, 1 year, and 2 years postoperatively.

Compared with patients with residual LAA tissue, those with complete amputation showed greater systolic BP reductions from baseline at 12 hours (-18%), 24 hours (-14%), 48 hours (-15%), 1 month (-20%), and 1 year (-16%). BP returned to baseline by 2 years. Lower LAA remnant-to-left atrial (LA) volume ratios predicted greater early BP decreases.

These results indicate that loss of compliant LAA tissue may increase atrial distension, activating mechanoreceptors and reducing sympathetic tone via sympathoinhibition and renin–angiotensin–aldosterone system (RAAS) suppression. Further studies are warranted to confirm long-term neurohumoral effects.