Purpose: The left atrial appendage (LAA) is a well-known source of atrial natriuretic peptide (ANP) and therefore plays an important role in homeostasis. The neurohormonal impact of epicardial exclusion of the LAA with the LARIAT procedure is unknown. In this proof-of-concept study, we postulated that LAA exclusion would impact homeostasis as evidenced by changes in electrolytes and blood pressure (BP).
Methods: A total of 76 patients who underwent successful LAA exclusion were enrolled in this retrospective observational study utilizing a prospective registry. Electrolytes, BP, and heart rate (HR) were monitored before LARIAT and post-LARIAT (24 and 72 h and 6 months).
Results: There was a significant reduction of systolic BP (mmHg) at 24 h (113.3 ± 16.0; p < 0.0001) and 72 h (119.0 ± 18.4 mmHg; p < 0.0001) post-LARIAT when compared with pre-LARIAT BP (138.2 ± 21.3). The reduction in systolic BP persisted at 6-month follow-up (128.8 ± 17.3; p = 0.0005). There was significant reduction in serum sodium (mmol/L) at 24 h (135.4 ± 3.6; p < 0.0001) and 72 h (136.3 ± 3.7; p < 0.001) post-LARIAT when compared to pre-LARIAT (138.7 ± 3.2). The reduction in sodium was not persistent at 6-month follow-up (138.4 ± 3.3; p = 0.453).
Conclusions: LAA exclusion results in an early and persistent decrease in systolic BP. Additionally, there is an early decline in serum sodium, which normalizes at long-term follow-up. The underlying mechanism leading to these changes is not entirely clear; however, it is likely related to neurohormonal changes post LAA exclusion.