Left atrial appendage contributes to left atrial booster function after the maze procedure: quantitative assessment with multidetector computed tomography.

OBJECTIVE

Although the left atrial appendage (LAA) is excised to prevent thrombosis in the maze procedure, it remains unclear whether LAA is retained in expectation of LAA booster function. Therefore, we quantitatively assessed LAA size and function after the maze procedure in patients with chronic atrial fibrillation (AF) and mitral valve disease (MVD), and compared with those in patients with sinus rhythm after coronary artery bypass grafting (CABG).

METHODS

We studied 23 patients (maze group: 65.0 + or - 9.2 (SD) years) undergoing the maze procedure for chronic AF and mitral valve surgery and 16 patients having sinus rhythm after CABG (CABG group: 66.5 + or - 9.3 years). The maze procedure was conducted by radiofrequency (RF) ablation and LAA was preserved in all cases. Left atrium (LA) and LAA volume and booster function were quantitatively evaluated by multidetector computed tomography (MDCT) at 11.7 + or - 10.4 months (maze group) and 16.8 + or - 19.9 months (CABG group) after the surgery.

RESULTS

In all 23 patients of the maze group, sinus rhythm was well restored. LAA was clearly visualised without thrombi in all 39 patients. The maximal LA volume in the maze group was 128.8 + or - 54.6 ml, being larger than 105.3 + or - 36.1 ml in the CABG group. LA ejection fraction (EF) in the maze group was 16.1 + or - 7.0%, being significantly lower than 26.8 + or - 8.7% in the CABG group. Meanwhile, the maximal LAA volume in the maze group was significantly larger (16.9 + or - 7.3 ml vs 8.4 + or - 4.7 ml), but LAA EF (34.1 + or - 12.8% vs 36.1 + or - 7.4%) was comparable in the two groups.

CONCLUSION

LAA largely contributes to LA booster function, particularly in the maze group, because LA booster function is deteriorated in this group of patients.