Background: Unmodified maze III operations show long-term eradication of atrial fibrillation (AF) in more than 85% of patients with or without structural heart disease. The effect of this procedure on atrial volumes is not known.
Methods: Two patient populations were studied: (1) patients undergoing unmodified maze III operations combined with surgical structural heart disease, mostly mitral valve operations (group A; n = 32); and (2) patients with only AF selected for unmodified maze III operations (group B; n = 32). In groups A and B, transthoracic Doppler echocardiographic studies were prospectively made preoperatively, and at 3 and 12 months postoperatively. Left and right atrial dimensions and volumes and atrial contractions were determined and compared with base line patient characteristics and 12 months arrhythmia outcomes.
Results: One year postoperatively all patients were alive. In groups A and B, 92% were free of AF and other atrial arrhythmias. A significant reduction of left atrial volume at 1 year postoperatively was apparent in group A, whereas the left atrial volume did not change significantly in group B. The reduction observed in group A was not related to postoperative age, type or duration of AF, or late atrial arrhythmia outcome. In both groups the right atrial volume remained unchanged at 12 months postoperatively.
Conclusions: The unmodified maze III operation does not affect atrial volume in patients without structural heart disease. In patients with structural heart disease, the mitral valve operation contributes to the reduction of left atrial volume and dimension by improving the hemodynamic condition.