Postoperative 4-chamber cardiac function and outcomes following biatrial or left atrial Maze procedure for concomitant atrial fibrillation

Objectives: Effects of Maze procedure lesions on subsequent atrial/ventricular function, and clinical outcomes are not well delineated. We analyzed relationships among preoperative atrial strain, postoperative cardiac function, and clinical outcomes after a biatrial Maze procedure or left atrial Maze procedure. Methods: Between June 2004 and December 2018, 822 consecutive patients underwent a biatrial Maze procedure (n = 290) or left atrial Maze procedure (n = 532) for atrial fibrillation ablation in conjunction with mitral valve surgery. Echocardiograms were available in 290 patients for retrospective strain and volume measurements. Associations between preoperative mechanics and 1-year atrial fibrillation recurrence, stroke, and mortality were assessed. Results: There was advanced disease, larger atrial volumes, and worse preoperative 4-chamber mechanics in the biatrial Maze procedure compared with the left atrial Maze procedure. However, the biatrial Maze procedure group showed greater improvement in right atrial strain, whereas left atrial strain increased modestly but remained below normal in both groups; left ventricular global longitudinal strain declined similarly. At 1 year, chamber function was comparable between procedures. Preoperative left atrial strain predicted 1-year atrial fibrillation recurrence; lower left atrial strain was associated with late stroke and 1-year mortality. Reduced right atrial and enlarged left atrial and right atrial volumes identified high-risk patients and added prognostic information for atrial fibrillation recurrence and mortality. Conclusions: Preoperative left atrial and right atrial strain and volumes provide risk stratification for atrial fibrillation recurrence, late stroke, and 1-year mortality after Maze surgery. There was better recovery of right atrial function in the biatrial Maze procedure. Patients with right atrial enlargement or dysfunction may benefit from the biatrial Maze procedure. Left atrial reservoir strain is the dominant prognostic marker for atrial fibrillation recurrence, stroke, and death after any Maze procedure and can guide decision-making.